Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2017	Feb. 09, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document type	10-K
Document period end date	Dec. 31, 2017
Amendment flag	false
Entity registrant name	DIODES INC /DEL/
Entity central index key	0000029002
Entity current reporting status	Yes
Entity voluntary filers	No
Current fiscal year end date	--12-31
Entity filer category	Large Accelerated Filer
Entity well known seasoned issuer	Yes
Entity common stock shares outstanding		49,140,136
Entity public float			$ 714,636,068
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	DIOD

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 203,820	$ 247,802
Short-term investments	4,558	29,842
Accounts receivable, net of allowances of $4,480 and $2,141 at December 31, 2017 and December 31, 2016, respectively	200,112	217,217
Inventories	216,506	193,483
Prepaid expenses and other	37,328	44,438
Total current assets	662,324	732,782
Property, plant and equipment, net	459,169	401,988
Deferred income tax	40,580	56,047
Goodwill	134,187	129,412
Intangible assets, net	156,445	174,876
Other	35,968	33,447
Total assets	1,488,673	1,528,552
Current liabilities:
Line of credit	1,008
Accounts payable	108,001	87,600
Accrued liabilities	99,301	71,562
Income tax payable	18,216	11,855
Current portion of long-term debt	20,636	14,356
Total current liabilities	247,162	185,373
Long-term debt, net of current portion	247,492	413,126
Deferred tax liabilities	25,176	28,213
Other long-term liabilities	94,925	81,373
Total liabilities	614,755	708,085
Commitments and contingencies (See Note 16)
Stockholders' equity
Preferred stock - par value $1.00 per share; 1,000,000 shares authorized; no shares issued or outstanding
Common stock - par value $0.66 2/3 per share; 70,000,000 shares authorized; 49,130,090 and 48,219,376, issued and outstanding at December 31, 2017 and December 31, 2016, respectively	33,727	32,919
Additional paid-in capital	386,338	354,574
Retained earnings	532,687	530,215
Treasury stock, at cost, 1,457,206 and 1,157,206 shares held at December 31, 2017 and December 31, 2016, respectively	(37,768)	(29,023)
Accumulated other comprehensive loss	(83,480)	(112,666)
Total stockholders' equity	831,504	776,019
Noncontrolling interest	42,414	44,448
Total equity	873,918	820,467
Total liabilities and stockholders' equity	$ 1,488,673	$ 1,528,552

CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Accounts receivable, allowance	$ 4,480	$ 2,141
Preferred stock par value	$ 1.00	$ 1.00
Preferred stock shares authorized	1,000,000	1,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock par value	$ 0.666	$ 0.666
Common stock shares authorized	70,000,000	70,000,000
Common stock shares issued	49,130,090	48,219,376
Common stock shares outstanding	49,130,090	48,219,376
Treasury stock, shares	1,457,206	1,157,206

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 1,054,204	$ 942,162	$ 848,904
Cost of goods sold	697,428	655,239	600,321
Gross profit	356,776	286,923	248,583
Operating expenses
Selling, general and administrative	167,639	158,256	139,245
Research and development	77,877	69,937	57,027
Amortization of acquisition related intangible assets	18,798	20,478	8,596
Impairment of fixed assets	2,211	114	1,672
Restructuring	10,137	12
Other operating expenses	(246)	70	(59)
Total operating expenses	276,416	248,867	206,481
Income from operations	80,360	38,056	42,102
Other (expense)/income
Interest income	1,475	1,357	1,006
Interest expense	(13,448)	(13,257)	(4,232)
Gain on securities carried at fair value			400
Foreign currency (loss) gain, net	(7,995)	2,171	1,257
Impairment of cost-basis investment		(3,218)
Other income (expense)	2,199	(74)	62
Total other (expense) income	(17,769)	(13,021)	(1,507)
Income before income taxes and noncontrolling interest	62,591	25,035	40,595
Income tax provision	62,325	6,558	14,082
Net income	266	18,477	26,513
Less: net (income) loss attributable to noncontrolling interest	(2,071)	(2,542)	(2,239)
Net (loss) income attributable to common stockholders	$ (1,805)	$ 15,935	$ 24,274
(Loss) earnings per share attributable to common stockholders
Basic	$ (0.04)	$ 0.33	$ 0.50
Diluted	$ (0.04)	$ 0.32	$ 0.49
Number of shares used in computation
Basic	48,824	48,597	48,210
Diluted	48,824	49,789	49,500

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest [Abstract]
Net income	$ 266	$ 18,477	$ 26,513
Unrealized (loss) gain on defined benefit plan, net of tax	(4,897)	(7,777)	4,399
Unrealized gain on interest rate swap, net of tax	1,018	1,506
Unrealized foreign currency gain (loss), net of tax	33,065	(21,979)	(20,413)
Comprehensive income (loss)	29,452	(9,773)	10,499
Less: Comprehensive income attributable to noncontrolling interest	(2,071)	(2,542)	(2,239)
Total comprehensive income (loss) attributable to common stockholders	$ 27,381	$ (12,315)	$ 8,260

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Total Diodes Incorporated Stockholders' Equity	Noncontrolling Interest
BALANCE at Dec. 31, 2014	$ 810,167	$ 31,729		$ 314,942	$ 490,006	$ (68,402)	$ 768,275	$ 41,892
Common stock shares beginning at Dec. 31, 2014		47,591,000
Total comprehensive income	10,499				24,274	(16,014)	8,260	2,239
Acquisition of noncontrolling interest	3,521							3,521
Common stock issued for share-based plans	10,198	$ 675		9,523			10,198
Common stock issued for share-based plans, shares		1,023,000
Net excess tax benefit from share-based compensation	(4,029)			(4,029)			(4,029)
Stock buyback	(11,009)		$ (11,009)				(11,009)
Stock buyback, shares			(466,000)
Share-based compensation	18,970			18,970			18,970
Restricted awards related to Pericom acquisition	4,680			4,680			4,680
BALANCE at Dec. 31, 2015	842,997	$ 32,404	$ (11,009)	344,086	514,280	(84,416)	795,345	47,652
Common stock shares ending at Dec. 31, 2015		48,614,000	(466,000)
Total comprehensive income	(9,773)				15,935	(28,250)	(12,315)	2,542
Dividends to noncontrolling interest	(5,746)							(5,746)
Common stock issued for share-based plans	120	$ 515		(395)			120
Common stock issued for share-based plans, shares		762,000
Net excess tax benefit from share-based compensation	(567)			(567)			(567)
Stock buyback	$ (18,014)		$ (18,014)				(18,014)
Stock buyback, shares	(691,196)		(691,000)
Share-based compensation	$ 13,978			13,978			13,978
Tax related to net share settlement	(2,528)			(2,528)			(2,528)
BALANCE at Dec. 31, 2016	$ 820,467	$ 32,919	$ (29,023)	354,574	530,215	(112,666)	776,019	44,448
Common stock shares ending at Dec. 31, 2016	48,219,376	49,376,000	(1,157,000)
Total comprehensive income	$ 29,452				(1,805)	29,186	27,381	2,071
Noncontrolling interests	476			(165)			(165)	641
Dividends to noncontrolling interest	(4,746)							(4,746)
Adoption of new accounting standard, ASU 2016-09	5,048			771	4,277		5,048
Common stock issued for share-based plans	13,606	$ 808		12,798			13,606
Common stock issued for share-based plans, shares		1,211,000
Stock buyback	$ (8,745)		$ (8,745)				(8,745)
Stock buyback, shares	(300,000)		(300,000)
Share-based compensation	$ 18,638			18,638			18,638
Tax related to net share settlement	(278)			(278)			(278)
BALANCE at Dec. 31, 2017	$ 873,918	$ 33,727	$ (37,768)	$ 386,338	$ 532,687	$ (83,480)	$ 831,504	$ 42,414
Common stock shares ending at Dec. 31, 2017	49,130,090	50,587,000	(1,457,000)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net income	$ 266	$ 18,477	$ 26,513
Adjustments to reconcile net income to net cash provided by operating activities, net of effects of acquisitions:
Depreciation	76,883	78,482	71,504
Amortization of intangibles	18,798	20,483	8,596
Amortization of debt issuance costs	514	1,889	660
Share-based compensation	18,609	14,029	18,970
Excess tax benefit from share-based compensation		(1,078)	(829)
(Gain) loss on disposal of property, plant and equipment	1,969	1,091	1,440
(Gain) on securities carried at fair value			(400)
Deferred income taxes	25,326	(15,978)	1,484
Other	(1,814)	1,811	(135)
Changes in operating assets:
Accounts receivable	22,261	533	(9,710)
Inventories	(17,199)	5,176	(2,165)
Prepaid expenses and other current assets	1,494	2,456	12,115
Changes in operating liabilities:
Accounts payable	17,313	2,640	(8,617)
Accrued liabilities	13,079	(3,158)	8,365
Other liabilities	4,495	(8,623)	(1,015)
Income taxes (refundable) payable	(871)	6,512	(8,665)
Net cash provided by operating activities	181,123	124,742	118,111
Investing Activities
Acquisitions, net of cash acquired			(348,887)
(Increase) decrease in restricted cash	624	(944)	786
Purchases of short-term investments	(12,205)	(23,459)	(57,878)
Sales of short-term investments	38,600	56,168	75,834
Purchases of equity securities			(4,553)
Proceeds from sale of equity securities			8,652
Purchases of property, plant and equipment	(111,161)	(58,549)	(133,244)
Proceeds from sales of property, plant and equipment	1,219	156	143
Subsidies and grants	6,968		380
Other	(2,332)	(723)	(679)
Net cash used in investing activities	(78,287)	(27,351)	(459,446)
Financing Activities
Advance on lines of credit and short-term debt	3,375	9,000	1,228
Repayments on lines of credit and short-term debt	(2,391)	(9,000)	(4,287)
Taxes related to net share settlement		(2,528)
Net proceeds from the issuance of common stock	13,606	120	10,192
Excess taxes (paid) benefit from share-based compensation	(278)	1,078	829
Proceeds from long-term debt	44,500	43,500	391,200
Debt issuance costs	(111)	(2,045)	(1,270)
Repayments of long-term debt	(204,374)	(79,913)	(65,986)
Repayments of capital lease obligations	(587)	(19)	(218)
Purchase of treasury stock	(8,745)	(18,014)	(11,009)
Dividend distribution to noncontrolling interest	(5,754)	(4,869)
Other	2,575	(768)	683
Net cash provided by (used in) financing activities	(158,184)	(63,458)	321,362
Effect of exchange rate changes on cash and cash equivalents	11,366	(4,566)	(4,592)
(Decrease) increase in cash and cash equivalents	(43,982)	29,367	(24,565)
Cash and cash equivalents, beginning of year	247,802	218,435	243,000
Cash and cash equivalents, end of year	203,820	247,802	218,435
Cash paid during the year for:
Interest	13,547	11,708	2,799
Income taxes	30,447	17,099	17,229
Non-cash activities:
(Increase) decrease property, plant and equipment purchased on accounts payable	(14,081)	6,393	(4,498)
Acquisition:
Fair value of assets acquired			496,625
Fair value of liabilities assumed			(88,284)
Less cash acquired			(54,774)
Net assets acquired			353,567
Pericom
Non-cash activities:
Share-based awards issued			$ (4,680)
Noncontrolling Interest
Non-cash activities:
Decrease (increase) in dividend accrued for noncontrolling interest	$ 1,008	$ (1,008)

Summary of Operations and Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Summary of Operations and Significant Accounting Policies

Note 1 – Summary of Operations and Significant Accounting Policies

Nature of operations – Diodes Incorporated and its subsidiaries (collectively, the “Company” or “we” or “our”) is a leading global manufacturer and supplier of high-quality application specific standard products within the broad discrete, logic, analog and mixed-signal semiconductor markets. Diodes serves the consumer electronics, computing, communications, industrial, and automotive markets. Diodes’ products include diodes, rectifiers, transistors, MOSFETs, protection devices, function-specific arrays, logic, amplifiers and comparators, Hall-effect and temperature sensors, power management devices, including LED drivers, AC-DC converters and controllers, DC-DC switching and linear voltage regulators, and voltage references along with special function devices, such as USB power switches, load switches, voltage supervisors, and motor controllers. Diodes’ corporate headquarters and Americas’ sales office are located in Plano, Texas and Milpitas, California. Design, marketing, and engineering centers are located in Plano; Milpitas; Taipei, Taiwan; Taoyuan City, Taiwan; Zhubei City, Taiwan; Manchester, England; and Neuhaus, Germany. Diodes’ wafer fabrication facilities are located in Manchester and Shanghai, China. Diodes has assembly and test facilities located in Shanghai, Jinan, Chengdu, and Yangzhou, China, as well as in Hong Kong, Neuhaus and Taipei. Additional engineering, sales, warehouse, and logistics offices are located in Taipei; Hong Kong; Manchester; Shanghai; Shenzhen, China; Seongnam-si, South Korea; and Munich, Germany, with support offices throughout the world. Our products are sold primarily throughout Asia, North America and Europe. During 2017, we shut down and transferred our wafer fabrication operation located in Lee’s Summit, MO, (“KFAB”) to other Company-owned wafer fabrication plants and external foundries. See Note 18 below for additional information related to the KFAB shutdown.

On November 24, 2015 we acquired Pericom Semiconductor Corporation. Pericom designs, develops and markets high-performance integrated circuits (“ICs”) and frequency control products (“FCPs”) used in many of today’s advanced electronic systems. ICs include functions that support the connectivity, timing and signal conditioning of high-speed parallel and serial protocols that transfer data among a system’s microprocessor, memory and various peripherals, such as displays and monitors, and between interconnected systems. FCPs are electronic components that provide frequency references such as crystals and oscillators for computer, communication and consumer electronic products. Analog, digital and mixed-signal ICs, together with FCPs enable higher system bandwidth and signal quality, resulting in better operating reliability, signal integrity, and lower overall system cost in applications such as notebook computers, servers, network switches and routers, storage area networks, digital TVs, cell phones, GPS and digital media players. Analog, digital and mixed-signal ICs, together with FCPs enable higher system bandwidth and signal quality, resulting in better operating reliability and signal integrity, and lower overall system cost in applications such as notebook computers, servers, network switches and routers, storage area networks, digital TVs, cell phones, GPS and digital media players.

Principles of consolidation – The consolidated financial statements include the accounts of Diodes Incorporated, its wholly-owned subsidiaries and its controlled majority-owned subsidiaries. We account for equity investments in companies over which we have the ability to exercise significant influence, but do not hold a controlling interest, under the equity method, and we record our proportionate share of income or losses in interest and other, net in the consolidated statements of income. All significant intercompany balances and transactions have been eliminated.

Use of estimates – The preparation of financial statements in conformity with generally accepted accounting principles in the United States of America (“GAAP”) requires that management make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The level of uncertainty in estimates and assumptions increases with the length of time until the underlying transactions are completed. Actual results may differ from these estimates in amounts that may be material to the consolidated financial statements and accompanying notes.

Revenue recognition – Net sales (revenue) are recognized when there is persuasive evidence that an arrangement exists, when delivery has occurred, when the price to the buyer is fixed or determinable and when collectability of the receivable is reasonably assured. These elements are met when title to the products is passed to the buyers, which is generally when product is shipped to the customers. Generally, we recognize net sales upon shipment to manufacturers (direct ship) as well as upon sales to distributors using the “sell in” model, which is when product is shipped to the distributors (point of purchase).

Certain customers have limited rights of return and/or are entitled to price adjustments on products held in their inventory or upon sale to their end customers. We reduce net sales in the period of sale for estimates of product returns, distributor price adjustments and other allowances. Our reserve estimates are based upon historical data as well as projections of sales, distributor inventories, price adjustments, average selling prices and market conditions.

We record allowances/reserves for the following items: (i) ship and debit, which arise when we, from time to time based on market conditions, issue credit to certain distributors upon their shipments to their end customers; (ii) stock rotation, which are contractual obligations that permit certain distributors, up to four times a year, to return a portion of their inventory based on historical shipments to them in exchange for an equal and offsetting order; and (iii) price protection, which arise when market conditions cause average selling prices to decrease and we issue credit to certain distributors on their inventory.

Ship and debit reserves are recorded as a reduction to net sales with a corresponding reduction to accounts receivable. Stock rotation reserves are recorded as a reduction to net sales with a corresponding reduction to cost of goods sold for the estimated cost of inventory that is expected to be returned. Price protection reserves are recorded as a reduction to net sales with a corresponding increase in accrued liabilities. Net sales are reduced in the period of sale for estimates of product returns and other allowances including distributor adjustments, which were approximately $158.1 million, $132.9 million and $113.5 million in 2017, 2016 and 2015, respectively.

Product warranty – We generally warrant our products for a period of one year from the date of sale. Historically, warranty expense has not been material.

Cash, cash equivalents, and short-term investments – We consider all highly liquid investments with maturity of three months or less at the date of purchase to be cash equivalents. We currently maintain substantially all of our day-to-day operating cash balances with major financial institutions. We hold short-term investments consisting of time deposits, which are highly liquid with maturity dates greater than three months at the date of purchase. Generally, we can access these investments in a relatively short amount of time but in doing so we generally forfeit a portion of interest income. See Note 2 below for additional information regarding fair value of financial instruments.

Allowance for doubtful accounts – We evaluate the collectability of our accounts receivable based upon a combination of factors, including the current business environment and historical experience. If we are aware of a customer’s inability to meet its financial obligations, we record an allowance to reduce the receivable to the amount we reasonably believe will be collected from the customer. For all other customers, we record an allowance based upon the amount of time the receivables are past due. If actual accounts receivable collections differ from these estimates, an adjustment to the allowance may be necessary with a resulting effect on operating expense. Accounts receivable are presented net of valuation allowance, which were approximately $4.5 million in 2017 and $2.1 million 2016.

Inventories – Inventories are stated at the lower of cost or net realizable value. Cost is determined principally by the first-in, first-out method. Cost includes materials, labor, and manufacturing overhead related to the purchase and production of inventories. Any write-down of inventory to the lower of cost or net realizable value at the close of a fiscal period creates a new cost basis that subsequently would not be marked up based on changes in underlying facts and circumstances. On an on-going basis, we evaluate inventory for obsolescence and slow-moving items. This evaluation includes analysis of sales levels, sales projections, and purchases by item, as well as raw material usage related to our manufacturing facilities. If our review indicates a reduction in utility below carrying value, we reduce inventory to a new cost basis. If future demand or market conditions are different than our current estimates, an inventory adjustment to write down inventory may be required, and would be reflected in cost of goods sold in the period the revision is made.

Property, plant and equipment – Purchased property, plant and equipment is recorded at historical cost, and property, plant and equipment acquired in a business combination is recorded at fair value on the date of acquisition. Property, plant and equipment is depreciated using straight-line methods over the estimated useful lives, which range from 20 to 55 years for buildings and 3 to 10 years for machinery and equipment. The estimated lives of leasehold improvements range from 3 to 5 years, and are amortized over the shorter of the remaining lease term or their estimated useful lives.

Goodwill and other indefinite lived intangible assets – Goodwill and indefinite lived assets are tested for impairment on an annual basis or when an event or changes in circumstances indicate that its carrying value may not be recoverable. Goodwill impairment is tested at the reporting unit level, which is defined as an operating segment or one level below the operating segment. Diodes has one operating segment. No goodwill impairment occurred in 2017, 2016, or 2015. Goodwill is reviewed for impairment using either a qualitative assessment or a quantitative goodwill impairment test. If we choose to perform a qualitative assessment and determine the fair value more likely than not exceeds the carrying value, no further evaluation is necessary. When we perform the quantitative goodwill impairment test, we compare fair value to carrying value, which includes goodwill. If fair value of exceeds carrying value, the goodwill is not considered impaired. If the carrying value is higher than the fair value, the difference would be recognized as an impairment loss.

Impairment of long-lived assets – Our long-lived assets are reviewed whenever events or changes in circumstances indicate that the carrying value may not be recoverable. We consider assets to be impaired if the carrying value exceeds the undiscounted projected cash flows from operations. If impairment exists, the assets are written down to fair value or to the projected discounted cash flows from related operations. As of December 31, 2017, we expect the remaining carrying value of assets to be recoverable. During 2017 we had recognized an impairment of long-lived assets related to the KFAB fixed assets. See Note 18 below for additional information related to the KFAB shut down.

Business combinations – The Company recognizes all (and only) the assets acquired and liabilities assumed in the transaction and establishes the acquisition-date fair value as the measurement objective for all assets acquired and liabilities assumed in a business combination. Certain provisions prescribe, among other things, the determination of acquisition-date fair value of consideration paid in a business combination (including contingent consideration) and the exclusion of transaction and acquisition-related restructuring costs from acquisition accounting. During the normal course of business the Company makes acquisitions. In the event that an individual acquisition (or an aggregate of acquisitions) is material, appropriate disclosure of such acquisition activity is provided. See Note 19 for additional information regarding business combinations.

Income taxes – Income taxes are accounted for using an asset and liability approach whereby deferred tax assets and liabilities are recorded for differences in the financial reporting bases and tax bases of our assets and liabilities. If it is more likely than not that some portion of deferred tax assets will not be realized, a valuation allowance is recorded.

GAAP prescribes a comprehensive model for how companies should recognize, measure, present, and disclose in their financial statements uncertain tax positions taken or expected to be taken on a tax return. Tax positions shall initially be recognized in the financial statements when it is more likely than not the position will be sustained upon examination by the tax authorities. Such tax positions shall initially and subsequently be measured as the largest amount of tax benefit that is greater than 50% likely of being realized upon ultimate settlement with the tax authority assuming full knowledge of the position and all relevant facts. All deferred income taxes are classified as noncurrent assets or noncurrent liabilities on the consolidated balance sheet as of December 31, 2017 and 2016, respectively.

The Tax Cuts and Jobs Act (the “Tax Act”) was enacted on December 22, 2017. The Tax Act reduces the U.S. federal corporate tax rate from 35% to 21%, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred, provides an exemption from U.S. federal tax for dividends received from foreign subsidiaries, and creates new taxes on certain foreign sourced earnings. As of the completion of these financial statements and related disclosures, we have not completed our accounting for the tax effects of the Tax Act; however, as described below, we have made a reasonable estimate of such effects and recorded a provisional tax expense of approximately $45.9 million, which is included as a component of income tax expense from continuing operations in the fourth quarter of 2017. This provisional tax expense incorporates assumptions made based upon the Company’s current interpretation of the Tax Act, and may change as we receive additional clarification and implementation guidance and as the interpretation of the Tax Act evolves. In accordance with SEC Staff Accounting Bulletin No. 118, the Company will finalize the accounting for the effects of the Tax Act no later than the fourth quarter of 2018. Future adjustments made to the provisional effects will be reported as a component of income tax expense from continuing operations in the reporting period in which any such adjustments are determined. See Note 11 for additional information.

Research and development costs – Internally-developed research and development costs are expensed as incurred. Acquired in-process research and development (“IPR&D”) is capitalized as an indefinite-lived intangible asset and evaluated periodically for impairment. When the project is completed, an expected life is determined and the IPR&D is amortized as an expense over the expected life.

Shipping and handling costs – Shipping and handling costs for products shipped to customers, which are included in selling, general and administrative expenses, were approximately $15.2 million, $14.2 million and $8.3 million for the twelve months ended December 31, 2017, 2016 and 2015, respectively.

Concentration of credit risk – Financial instruments, which potentially subject us to concentrations of credit risk, include trade accounts receivable. Credit risk is limited by the dispersion of our customers over various geographic areas, operating primarily in electronics manufacturing and distribution. We perform on-going credit evaluations of our customers, and generally require no collateral. Historically, credit losses have not been significant.

We currently maintain substantially all of our day-to-day cash balances and short-term investments with major financial institutions. Cash balances are usually in excess of Federal and/or foreign deposit insurance limits.

Derivative instruments and hedging activities - The Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. We maintain derivative financial instruments with major financial institutions of investment grade credit rating and monitor the amount of credit exposure to any one issuer. We believe there are no significant concentrations of risk associated with our derivative financial instruments.

Valuation of financial instruments – The carrying value of our financial instruments, including cash and cash equivalents, short-term investments, accounts receivable, accounts payable, credit line, and long-term debt approximate fair value due to their current market conditions, maturity dates and other factors.

Earnings per share – Basic earnings per share is calculated by dividing net earnings attributable to common stockholders by the weighted-average number of shares of Common Stock outstanding during the period. Diluted earnings per share is calculated similarly but includes potential dilution from the exercise of stock options and stock awards, except when the effect would be anti-dilutive. Earnings per share are computed using the “treasury stock method.”

For the twelve months ended December 31, 2017, 2016 and 2015, options and share grants outstanding totaling approximately 3.5 million shares, 1.4 million shares and 1.4 million shares have been excluded from the computation of diluted earnings per share because their effect was anti-dilutive.

	Twelve Months Ended December 31,
	2017			2016		2015
Earnings (numerator)
Net (loss) income attributable to common stockholders	$	(1,805	)	$	15,935	$	24,274

Shares (denominator)
Weighted average common shares outstanding (basic)		48,824			48,597		48,210
Dilutive effect of stock options and stock awards outstanding		-			1,192		1,290
Adjusted weighted average common shares outstanding (diluted)		48,824			49,789		49,500

(Loss) earnings per share attributable to common stockholders
Basic	$	(0.04	)	$	0.33	$	0.50
Diluted	$	(0.04	)	$	0.32	$	0.49

Share-based compensation – We use the Black-Scholes-Merton model to determine the fair value of stock options on the date of grant and recognize compensation expense for stock options on a straight-line basis. Restricted stock grants are measured based on the fair market value of the underlying stock on the date of grant and compensation expense is recognized on a straight-line basis over the requisite four-year service period.

The amount of compensation expense recognized using the Black-Scholes-Merton model requires us to exercise judgment and make assumptions relating to the factors that determine the fair value of our stock option grants. The fair value calculated by this model is a function of several factors, including the grant price, the expected future volatility, the expected term of the option and the risk-free interest rate of the option. The expected term and expected future volatility of the options require judgment. In addition, we are required to estimate the expected forfeiture rate and only recognize expense for those stock options expected to vest. We estimate the forfeiture rate based on historical experience, and to the extent our actual forfeiture rate is different from our estimate, share-based compensation expense is adjusted accordingly.

Treasury stock – Under a program authorized by our board of directors we have purchased shares of our common stock. These shares are recorded as treasury stock, at cost, as a reduction to stockholder’ equity.

Functional currencies and foreign currency translation – We translate the assets and liabilities of our non-U.S. dollar functional currency subsidiaries into U.S. dollars using exchange rates on the balance sheet date. Net sales and expense for these subsidiaries are translated at the weighted-average exchange rate during the period presented. Resulting translation adjustments are recorded as a separate component of accumulated other comprehensive income or loss within stockholders’ equity in the consolidated balance sheets. Included in other income are foreign exchange (losses) and gains of $(8.0) million, $2.2 million and $1.3 million for the twelve months ended December 31, 2017, 2016 and 2015, respectively.

Defined benefit plan – We maintain pension plans covering certain of our employees in the U.K. The overfunded or underfunded status of pension and postretirement benefit plans are recognized on the balance sheet. Actuarial gains and losses, and prior service costs or credits, are recognized in other comprehensive income (loss), net of tax effects, until they are amortized as a component of net periodic benefit cost. For financial reporting purposes, the net pension and supplemental retirement benefit obligations and the related periodic pension costs are calculated based upon, among other things, assumptions of the discount rate for plan obligations, estimated return on pension plan assets and mortality rates. These obligations and related periodic costs are measured using actuarial techniques and assumptions. The projected unit credit method is the actuarial cost method used to compute the pension liabilities and related expenses. The expected long-term return on plan assets was determined based on historical and expected future returns of the various asset classes. The plan’s investment policy includes a mandate to diversify assets and invest in a variety of asset classes to achieve its expected long-term return and is currently invested in a variety of funds representing most standard equity and debt security classes. Trustees of the plan may make changes at any time.

Investment in joint ventures – Investment in joint ventures over which we have the ability to exercise significant influence and that, in general, are at least 20 percent owned are accounted for using the equity method of accounting. These investments are evaluated for impairment, in which an impairment loss would be recorded whenever a decline in the value of an equity investment below its carrying amount is determined to be “other than temporary.” In judging “other than temporary,” we consider the length of time and extent to which the fair value of the investment has been less than the carrying amount of the investment, the near-term and longer-term operating and financial prospects of the investee, and our longer-term intent of retaining the investment in the investee.

Noncontrolling interest - Noncontrolling interest primarily relates to the minority investors’ share of the earnings of certain China and Taiwan subsidiaries. Noncontrolling interests are a separate component of equity and not a liability. Increases or decreases in noncontrolling interest, due to changes in our ownership interest of the subsidiaries that leave control intact, are recorded as equity transactions. The noncontrolling interest in our subsidiaries and their equity balances are reported separately in the consolidated financial statements, and activities of these subsidiaries are included therein.

Contingencies – From time to time, we may be involved in a variety of legal matters that arise in the normal course of business. Based on information available, we evaluate the likelihood of potential outcomes. We record and disclose the appropriate liability when the amount is deemed probable and reasonably estimable. In addition, we do not accrue for estimated legal fees and other directly related costs as they are expensed as incurred.

Comprehensive income (loss) – GAAP generally requires that recognized revenue, expenses, gains and losses be included in net income. Although certain changes in assets and liabilities are reported as separate components of the equity section of the consolidated balance sheet, such items, along with net income, are components of comprehensive income or loss. The components of accumulated other comprehensive income or loss include foreign currency translation adjustments and unrealized gain or loss on defined benefit plan. Accumulated other comprehensive loss was approximately $83.5 million, $112.7 million and $84.4 million at December 31, 2017, 2016 and 2015, respectively.

There is no income tax expense or benefit associated with each component of comprehensive income. As of December 31, the accumulated balance for each component of comprehensive income is as follows:

	2017			2016
Unrealized foreign currency losses	$	(42,010	)	$	(75,075	)
Unrealized gain on interest rate swap, net of tax	$	2,524		$	1,506
Unrealized loss on defined benefit plan	$	(43,994	)	$	(39,097	)

Reclassifications – Certain immaterial amounts from prior periods have been reclassified to conform to the current years’ presentation.

Recently Accounting Pronouncements - The Financial Accounting Standards Board (“FASB”) issued the following Accounting Standards Updates (“ASU”) which could have potential impact to the Company’s financial statements:

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). This standard provides a single set of guidelines for revenue recognition to be used across all industries and requires additional disclosures. It is effective for annual and interim reporting periods beginning after December 15, 2017. We will adopt this standard in the first quarter of 2018, and will apply the standard using the modified retrospective method. Further, we will elect the following applicable practical expedients;

•

Recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that the entity otherwise would have recognized is one year or less;

•

Use the portfolio approach, in estimating variable consideration, which specifies the accounting for an individual contract with a customer;

•

Continue to expense shipping and handling as fulfillment activities; and

•

Continue to exclude sales taxes from the transaction price.

Our key revenue streams are Distribution and Original Equipment Manufacturer (“OEM”) sales, that combined comprise the majority of our business. The current pattern of revenue recognition for these revenue streams is point-in-time, and that will not change upon the adoption of the new standard. Further, we have identified a number of variable consideration components within our contracts with customers, and have determined there will be no related impact. We have also determined that the impact of accounting for costs incurred to obtain a contract is immaterial. The adoption of this standard will not have a material effect on our consolidated financial statements, but will require the Company to provide additional and revised disclosures beginning with our Form 10-Q filing for the first quarter of 2018.

ASU No. 2016-02, Leases (Topic 842) (“ASU 2016-02”) - In February 2016, the FASB issued ASU 2016-02, which amends the accounting treatment for leases. The amendments are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. Lessees and lessors may not apply a full retrospective transition approach. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2016-02 may have on its consolidated financial statements and has not elected early adoption as of the period ended December 31, 2017. During the second quarter of 2017 we engaged outside accounting consultants to assist us in the implementation of this new standard. The Company is in the process of assessing its outstanding leases.

ASU No. 2016-09, Compensation—Stock Compensation (Topic 718) Improvements to Employee Share-Based Payment Accounting - In March 2016, the FASB issued guidance to simplify the accounting for share-based payment transactions by requiring all excess tax benefits and deficiencies to be recognized in income tax expense or benefit in earnings, thus eliminating the requirement to classify the excess tax benefit and deficiencies as additional paid-in capital. Under the new guidance, an entity makes an accounting policy election to either estimate the expected forfeiture awards or account for forfeitures as they occur. We adopted ASU No. 2016-09 during the first quarter of 2017 and as a result will account for forfeitures as they occur. The effect of the adoption related to the income tax portion was an increase of $4.8 million to retained earnings and to deferred income tax assets. The effect of the adoption related to forfeitures was an increase to additional paid in capital of $0.8 million, an increase to deferred tax assets of $0.3 million and a decrease to retained earnings of $0.5 million.

ASU No. 2017-09, Compensation – Stock Compensation (Topic 718) Scope of Modification Accounting - In May 2017, the FASB issued guidance to clarify when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The guidance is effective prospectively for all companies for annual periods beginning on or after December 15, 2017. Early adoption is permitted. We early adopted this standard in the third quarter of 2017. Adoption of this standard had no impact on the Company’s financial statements.

ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities – In August 2017, the FASB issued guidance that eliminates the requirement to separately measure and report hedge ineffectiveness. The guidance is effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within those years. Early adoption is permitted in any interim period or fiscal period before the effective date. The Company adopted ASU No. 2017-12 during the third quarter of 2017. In accordance with ASU 2017-12, the Company recognizes all reclassifications out of other comprehensive income (other than those related to a hedged transaction becoming probable of not occurring) in the same income statement line item in which the earnings effect of the hedged item is being presented, which is consistent with the Company’s current policy. Adoption of this standard had no impact on the Company’s financial statements.

ASU No. 2015-11, Simplifying the Measurement of Inventory (“ASU 2015-11”). This standard requires in scope inventory to be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments do not apply to inventory that is measured using LIFO or the retail inventory method. The amendments apply to all other inventory, which includes inventory that is measured using first-in, first-out (“FIFO”) or average cost. The standard is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years and requires prospective application. We adopted this standard in the first quarter of 2017. The adoption had no material impact on our financial statements.

ASU No. 2016-15, Statement of Cash Flows (Topic 230) Classification of Certain Cash Receipts and Cash Payments - In November 2016, the FASB issued an accounting standard update related to the presentation of restricted cash in the Company’s Consolidated Statement of Cash Flows. The update requires that the Consolidated Statement of Cash Flows explain the change during the period in cash, cash equivalents, and restricted cash. Restricted cash should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the Consolidated Statement of Cash Flows. This accounting guidance is effective for the Company beginning in the first quarter of 2018. The Company will adopt this guidance for our fiscal year beginning January 1, 2018, and the guidance will result in changes to the Company’s Consolidated Statement of Cash Flows such that restricted cash amounts will be included in the beginning-of-period and end-of-period cash and cash equivalents totals, and will have no impact on our results of operations.

ASU No. 2016-16, Income Taxes (Topic 740) Intra-Entity Transfers of Assets Other Than Inventory. This standard requires that an entity should recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party. The amendments in this standard are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods. The Company does not expect the adoption of this new standard to have a material effect on its financial statements.

ASU No. 2017-01, Clarifying the Definition of a Business. This standard classifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. This update is effective for annual periods beginning after December 15, 2017, including interim periods within those annual reporting periods, and would only apply to future acquisitions.

ASU 2017-04, Intangibles—Goodwill and Other (Topic 350) Simplifying the Test for Goodwill Impairment. This standard simplifies the accounting for goodwill impairment. The guidance removes Step 2 of the goodwill impairment test, which requires a hypothetical purchase price allocation. Goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The revised guidance will be applied prospectively, and is effective for calendar year-end SEC filers for its annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company adopted this standard in the third quarter of 2017. Adoption of this standard had no impact on the Company’s financial statements.

Fair Value Measurements

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

Note 2 – Fair Value Measurements

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.

We use valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets and liabilities. The income approach uses valuation techniques to convert future amounts, such as cash flows or earnings, to a single present amount on a discounted basis. The cost approach is based on the amount that currently would be required to replace the service capacity of an asset (replacement costs). Valuation techniques should be consistently applied. Inputs to valuation techniques refer to the assumptions that market participants would use in pricing the asset or liability. Inputs may be observable, meaning those that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from independent sources, or unobservable, meaning those that reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. These two types of inputs create a three-tier fair value hierarchy that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows:

Level 1 Inputs - Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date.

Level 2 Inputs - Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (for example, interest rates, volatilities, prepayment speeds, loss severities, credit risks and default rates) or inputs that are derived principally from or corroborated by observable market data by correlation or other means.

Level 3 Inputs - Significant unobservable inputs that reflect an entity’s own assumptions that market participants would use in pricing the assets or liabilities.

As of December 31, 2017, we had short-term investments. Trading securities held at December 31, 2017, were purchased on the open market and unrealized gains and losses are included in other income (expense). The trading securities are valued under the fair value hierarchy using Level 1 Inputs. Short-term investments of $4.6 million consist of investments such as time deposits, which are highly liquid with maturity dates greater than three months at the date of purchase. See Note 17 for additional information related to our interest rate swaps and foreign currency hedges. Generally, we can access these investments in a relatively short amount of time but in doing so we generally forfeit a portion of earned and future interest income. The short-term investments are valued under the fair value hierarchy using Level 2 Inputs.

Financial assets and liabilities carried at fair value as of December 31, 2017 are classified in the following table:

Description	Fair Market Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Changes in Fair Values Included in Current Period Earnings
Short-term investments	$	4,558	$	2,586	$	1,972	$	-	$	-
Interest rate swaps and collars		3,884		-		3,884		-		-

Financial assets and liabilities carried at fair value as of December 31, 2016 are classified in the following table:

Description	Fair Market Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Changes in Fair Values Included in Current Period Earnings
Short-term investments	$	29,842	$	2,737	$	27,105	$	-	$	-
Interest rate swap assets		2,317		-		2,317		-		-

Certain financial assets and financial liabilities are measured at fair value on a non-recurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). We believe our long-term debt under our revolving credit facility approximates fair value and is valued under the fair value hierarchy using Level 2 Inputs. Financial assets and financial liabilities measured at fair value on a non-recurring basis were not significant at December 31, 2017 and 2016.

We also are responsible for a pension plan in the U.K. that holds investments carried at fair value. See Note 12 for additional information related to these pension plan investments.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Inventories

12 Months Ended

Dec. 31, 2017

Inventory Disclosure [Abstract]

Inventories

Note 3 – Inventories

Inventories, stated at the lower of cost or market value, at December 31 were:

	2017		2016
Finished goods	$	81,194	$	66,930
Work-in-progress		52,578		45,408
Raw materials		82,734		81,145
	$	216,506	$	193,483

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

Note 4 – Property, Plant and Equipment

Property, plant and equipment at December 31 were:

	2017			2016
Buildings and leasehold improvements	$	203,054		$	192,290
Machinery and equipment		774,138			685,249
		977,192			877,539
Less: Accumulated depreciation and amortization		(581,753	)		(535,407	)
		395,439			342,132
Construction in-progress		22,446			24,049
Land		41,284			35,807
	$	459,169		$	401,988

Depreciation and amortization of property, plant and equipment was $76.9 million, $78.5 million and $71.5 million for the years ended December 31, 2017, 2016 and 2015, respectively. We have capital lease obligations totaling approximately $1.0 million and $1.1 million and December 31, 2017 and 2016, respectively, included in other current liabilities and other long-term liabilities on the balance sheet.

Intangible Assets

12 Months Ended

Dec. 31, 2017

Intangible Assets Net Excluding Goodwill [Abstract]

Intangible Assets

Note 5 – Intangible Assets

Intangible assets subject to amortization at December 31 were as follows:

December 31, 2017
Intangible Assets	Useful life	Gross Carrying Amount		Accumulated Amortization			Currency Exchange			Net
Amortized intangible assets
Patents	5-15 years	$	11,823	$	(9,154	)	$	(242	)	$	2,427
Software license	3 years		1,212		(1,149	)		(63	)		-
Developed product technology	2-10 years		154,795		(53,925	)		(6,219	)		94,651
Customer relationships	12 years		62,093		(19,319	)		(1,650	)		41,124
Other	4 years		4,610		(4,512	)		(75	)		23
Total amortized intangible assets			234,533		(88,059	)		(8,249	)		138,225
Intangible assets with indefinite lives
In process research and development	Indefinite		8,914		-			-			8,914
Trademarks and trade names	Indefinite		10,303		-			(997	)		9,306
Total Intangible assets with indefinite lives			19,217		-			(997	)		18,220
Total intangible assets		$	253,750	$	(88,059	)	$	(9,246	)	$	156,445

December 31, 2016
Intangible Assets	Useful life	Gross Carrying Amount		Accumulated Amortization			Currency Exchange			Net
Amortized intangible assets
Patents	5-15 years	$	11,823	$	(8,431	)	$	(255	)	$	3,137
Software license	3 years		1,212		(1,149	)		(63	)		-
Developed product technology	2-10 years		153,009		(41,416	)		(6,299	)		105,294
Customer relationships	12 years		62,093		(13,915	)		(1,750	)		46,428
Other	4 years		4,610		(4,336	)		(75	)		199
Total amortized intangible assets			232,747		(69,247	)		(8,442	)		155,058
Intangible assets with indefinite lives
In process research and development	Indefinite		10,700		-			-			10,700
Trademarks and trade names	Indefinite		10,303		-			(1,185	)		9,118
Total Intangible assets with indefinite lives			21,003		-			(1,185	)		19,818
Total intangible assets		$	253,750	$	(69,247	)	$	(9,627	)	$	174,876

Amortization expense related to intangible assets subject to amortization was $18.8 million, $20.5 million and $8.6 million for the years ended December 31, 2017, 2016 and 2015, respectively.

Amortization of intangible assets is as follows:

2018	$	18,003
2019		17,498
2020		15,472
2021		14,775
2022		13,956
2023 and thereafter		58,521
Total	$	138,225

Goodwill

12 Months Ended

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill

NOTE 6 – GOODWILL

Changes in goodwill for the years ended December 31 were as follows:

Balance at December 31, 2015		132,913
Pericom measurement period adjustment		2,741
Foreign currency translation adjustment		(6,242	)
Balance at December 31, 2016		129,412
Foreign currency translation adjustment		4,775
Balance at December 31, 2017	$	134,187

Bank Credit Agreements and Other Short-Term and Long-Term Debt

12 Months Ended

Dec. 31, 2017

Long Term Debt By Current And Noncurrent [Abstract]

Bank Credit Agreements and Other Short-Term and Long-Term Debt

NOTE 7 – BANK CREDIT AGREEMENTS AND OTHER SHORT-TERM AND LONG-TERM DEBT

Short-term debt

Our Asia subsidiaries maintain credit facilities with several financial institutions through our foreign entities worldwide totaling $80.5 million. Generally our foreign credit lines are unsecured, uncommitted and may be repayable on demand. These credit facilities bear interest at LIBOR plus margin. Interest payments are due quarterly on outstanding amounts under the credit lines. The unused and available credit under the various facilities as of December 31, 2017, was approximately $78.7 million, net of a $1.0 million advance under the foreign credit line and $0.9 million credit used for import and export guarantee.

Long-term debt

We currently have a U.S. banking credit facility (the “U.S. Credit Facility”) under which we may draw up to $250 million on a revolving basis, in addition to a $250 million term loan. The U.S. Credit Facility matures October 26, 2021. The term loan portion of the U.S. Credit Facility is repayable in part through quarterly installments that increase over time from $3.1 million per quarter in 2016 to $9.4 million per quarter in the final year of the U.S. Credit Facility. We may, from time to time, request increases in the aggregate commitments under the U.S. Credit Facility of up to $200 million, subject to the lenders electing to increase their commitments or by means of the addition of new lenders, and subject to at least half of each increase in aggregate commitments being in the form of term loans, with the remaining amount of each increase being an increase in the amount of the revolving portion of the U.S. Credit Facility. The U.S. Credit Facility bears interest at LIBOR or similar indices plus a specified margin. The U.S. Credit Facility contains certain financial and non-financial covenants, including, but not limited to, a maximum consolidated leverage ratio, a minimum consolidated fixed charge coverage ratio, and restrictions on liens, indebtedness, investments, fundamental changes, dispositions, and restricted payments (including dividends and share repurchases). At December 31, 2017, we owed $268.8 million under the U.S. Credit Facility, $103.0 million of which was drawn under the revolving portion and $165.8 million of which was outstanding under the term loan. The obligations of the Borrowers under the U.S. Credit Facility are secured by substantially all of the assets of Diodes, including controlling interests in its first-tier subsidiaries, and by specified assets of certain of its subsidiaries.

Long-term debt balances as of December 31, consist of the following:

	2017			2016
Notes payable to Taiwan bank, original principal amount of TWD 132 million, variable interest (approximately 1.7% as of December 31, 2017), matures July 6, 2021.	$	1,271		$	1,466
Term loan and revolver		268,812			428,375
Total long-term debt		270,083			429,841
Less: Current portion		(20,636	)		(14,356	)
Less: Unamortized debt issuance costs		(1,955	)		(2,359	)
Long-term debt, net of current portion	$	247,492		$	413,126

The table below sets forth the annual contractual maturities of long-term debt at December 31, 2017:

2018	$	20,636
2019		26,892
2020		33,147
2021		189,408
Total long-term debt	$	270,083

Capital Lease Obligations

12 Months Ended

Dec. 31, 2017

Capital Lease Obligations [Abstract]

Capital Lease Obligations

NOTE 8 – CAPITAL LEASE OBLIGATIONS

Future minimum lease payments under capital lease agreements are summarized as follows:

For years ending December 31,

2018	$	658
2019		410
		1,068
Less: Interest		(27	)
Present value of minimum lease payments		1,041
Less: Current portion		(646	)
Long-term portion	$	395

At December 31, 2017, property under capital leases had a cost of $3.7 million, and the related accumulated depreciation was $2.6 million. Depreciation of assets held under capital lease is included in depreciation expense.

Accrued Liabilities and Other Long-Term Liabilities

12 Months Ended

Dec. 31, 2017

Accrued Liabilities Current And Noncurrent [Abstract]

Accrued Liabilities and Other Long-Term Liabilities

NOTE 9 – ACCRUED LIABILITIES AND OTHER LONG-TERM LIABILITIES

Accrued liabilities and other current liabilities at December 31 were:

	2017		2016
Accrued expenses	$	29,764	$	33,947
Compensation and payroll taxes		34,359		23,720
Equipment purchases		20,637		6,377
Accrued pricing adjustments		11,410		3,817
Accrued professional services		2,088		2,645
Other		1,043		1,056
	$	99,301	$	71,562

Other long-term liabilities at December 31 were:

	2017		2016
Accrued defined benefit plan	$	34,428	$	30,515
Unrecognized tax benefits		24,211		15,340
Deferred grant and subsidy		17,173		18,259
Income tax contingencies		8,319		8,163
Deferred compensation		8,870		6,433
Other		1,924		2,663
	$	94,925	$	81,373

Stockholders Equity	12 Months Ended
Stockholders Equity	Dec. 31, 2017
Stockholders Equity Note [Abstract]
Stockholder's Equity	NOTE 10 – STOCKHOLDERS’ EQUITY We have never declared or paid cash dividends on our Common Stock. Our U.S. Credit Facility permits us to pay dividends up to $3.0 million per fiscal year to its stockholders so long as we have not defaulted at the time of such dividend and no default would result from declaring or paying such dividend. The payment of dividends is within the discretion of our Board of Directors. See Note 7 for additional information regarding our credit agreements. During November 2015 the Company’s board of directors authorized a share repurchase plan to repurchase up to an aggregate of $100 million of the Company’s outstanding common stock, $0.66 2/3 par value per share. The share repurchase program is expected to continue through the end of 2019 unless extended or shortened by the Board of Directors. During 2017 the Company repurchased 300,000 of its common shares at a cost of $8.7 million and in 2016, the Company repurchased 691,196 of its common shares at a cost of $18.0 million. All purchases were made through open market transactions and were recorded as treasury stock.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

NOTE 11 – INCOME TAXES

Tax Cuts and Jobs Act

The Tax Act was enacted on December 22, 2017. The Tax Act reduces the U.S. federal corporate tax rate from 35% to 21%, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred, provides an exemption from U.S. federal tax for dividends received from foreign subsidiaries, and creates new taxes on certain foreign sourced earnings. As of the completion of these financial statements and related disclosures, we have not completed our accounting for the tax effects of the Tax Act; however, as described below, we have made a reasonable estimate of such effects and recorded a provisional tax expense of $45.9 million, which is included as a component of income tax expense from continuing operations in the fourth quarter of 2017. This provisional tax expense incorporates assumptions made based upon the Company’s current interpretation of the Tax Act, and may change as we receive additional clarification and implementation guidance and as the interpretation of the Tax Act evolves. In accordance with SEC Staff Accounting Bulletin No. 118, the Company will finalize the accounting for the effects of the Tax Act no later than the fourth quarter of 2018. Future adjustments made to the provisional effects will be reported as a component of income tax expense from continuing operations in the reporting period in which any such adjustments are determined.

The table below reflects the significant components of the provisional amount of tax expense recorded in the fourth quarter of 2017 and included as a component of income tax expense from continuing operations:

Component	Provisional Amount
Remeasurement of U.S. deferred tax assets and liabilities	$	2,913
Transition tax on foreign earnings		104,327
Foreign tax credits used to offset transition tax		(58,975	)
Other adjustments		(2,357	)
Total net tax expense related to the Tax Act	$	45,908

The Company expects to use net operating loss carryforwards and tax credits to completely offset any cash tax obligations resulting from the transition tax. The other components shown above represent noncash adjustments to tax expense.

Remeasurement of U.S. deferred tax assets and liabilities

We remeasured certain U.S. deferred tax assets and liabilities using the lower corporate income tax rate of 21%. However, we are still analyzing certain aspects of the Tax Act and refining our calculations, which could potentially affect the measurement of these deferred tax balances.

Transition tax on foreign earnings

The one-time transition tax is based on our total post-1986 earnings and profits (E&P) that we previously deferred from U.S. income taxes, and is net of indirect effects of unrecognized tax benefits. We have not yet completed our calculation of the total post-1986 E&P for the majority of our foreign subsidiaries. Further, the transition tax is based in part on the amount of those earnings held in cash and other specified assets. This amount may change when we finalize the calculation of post-1986 foreign E&P previously deferred from U.S. federal taxation and finalize the amounts held in cash or other specified assets.

No additional income taxes have been provided for any remaining undistributed foreign earnings not subject to the transition tax, or any additional outside basis difference inherent in these entities. Our undistributed foreign earnings, including those subject to the transition tax, continue to be indefinitely reinvested in foreign operations, with limited exceptions related to earnings of European subsidiaries. Determining the amount of unrecognized deferred tax liability related to any remaining undistributed foreign earnings not subject to the transition tax and additional outside basis difference in these entities (i.e., basis difference in excess of that subject to the one-time transition tax) is not practicable. We continue to evaluate the potential effects the Tax Act may have on our long term plans for capital investment across the geographies in which we operate.

Foreign tax credits used to offset transition tax

The Company is able to claim foreign tax credits against the incremental U.S. tax due on its previously deferred foreign earnings. However, we have not yet completed our calculation of the total amount of foreign taxes previously paid or accrued by the majority of our foreign subsidiaries that may be creditable against the transition tax. We expect these tax credits to generally be available to offset any cash tax liability resulting from the transition tax.

Other adjustments

We have not yet completed our analysis of the direct and indirect implications of the Tax Act on the Company’s tax attributes, such as tax credit carryforwards. Included in the provisional tax expense is the estimated effect of our change in judgment regarding realizability of foreign tax credits and R&D credits.

Income (loss) before income taxes	2017			2016			2015
U.S.	$	(72,668	)	$	(40,861	)	$	(21,091	)
Foreign		135,259			65,896			61,686
Total	$	62,591		$	25,035		$	40,595

The components of the income tax provision (benefit) are as follows for the years ended December 31:

	2017			2016			2015
Current tax provision (benefit)
Federal	$	-		$	-		$	12
Foreign		31,820			28,993			17,983
State		7			13			29
		31,827			29,006			18,024
Deferred tax provision (benefit)
Federal		30,186			(10,517	)		(2,739	)
Foreign		(2,352	)		(13,847	)		(1,063	)
State		(8	)		101			(228	)
		27,826			(24,263	)		(4,030	)
Liability for unrecognized tax benefits		2,672			1,815			88
Total income tax provision	$	62,325		$	6,558		$	14,082

Effective Tax Rate Reconciliation

Reconciliation between the effective tax rate and the statutory tax rates for the years ended December 31, 2017, 2016, and 2015 is as follows:

	2017						2016						2015
				Percent						Percent						Percent
				of pretax						of pretax						of pretax
	Amount			earnings			Amount			earnings			Amount			earnings
Federal tax	$	21,907			35.0		$	8,762			35.0		$	14,214			35.0
State income taxes, net of federal tax provision		(15	)		-			(65	)		(0.3	)		(152	)		(0.4	)
Foreign income taxed at lower tax rates		(23,515	)		(37.6	)		(6,955	)		(27.8	)		(10,126	)		(24.9	)
U.S. tax impact of foreign operations		6,726			10.7			324			1.3			2,046			5.0
Foreign withholding taxes		4,343			6.9			4,834			19.3			2,268			5.6
Research and development		(2,643	)		(4.2	)		(2,241	)		(9.0	)		(2,068	)		(5.1	)
Liability for unrecognized tax benefits		2,672			4.3			1,815			7.3			88			0.2
Valuation allowance		2,077			3.3			(2,600	)		(10.4	)		3,580			8.8
Provision-to-return adjustments		131			0.2			(61	)		(0.2	)		994			2.4
Employee stock-based compensation		1,537			2.5			-			-			-			-
U.S. Tax Cuts and Jobs Act		45,908			73.4			-			-			-			-
Other		3,197			5.1			2,745			11.0			3,238			8.1
Income tax provision	$	62,325			99.6		$	6,558			26.2		$	14,082			34.7

Uncertain Tax Positions

In accordance with the provisions related to accounting for uncertainty in income taxes, we recognize the benefit of a tax position if the position is “more likely than not” to prevail upon examination by the relevant tax authority. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

	2017			2016			2015
Balance at January 1,	$	28,849		$	26,503		$	19,488
Additions based on tax positions related to the current year		3,492			6,746			3,450
Additions for prior year tax positions		863			960			6,963
Reductions for prior year tax positions		(2,623	)		(5,360	)		(3,398	)
Balance at December 31,	$	30,581		$	28,849		$	26,503

If the $30.6 million of unrecognized tax benefits as of December 31, 2017 is recognized, approximately $27.2 million would affect the effective tax rate. It is reasonably possible that the amount of the unrecognized benefit with respect to certain of our unrecognized tax positions will significantly increase or decrease within the next 12 months. These changes may be the result of settlements of ongoing audits or competent authority proceedings. At this time, an estimate of the range of the reasonably possible outcomes cannot be made.

We file income tax returns in the U.S. federal jurisdiction and in various state and foreign jurisdictions. We are no longer subject to U.S. federal income tax examinations by tax authorities for tax years before 2008, or for the 2010 and 2011 tax years. We are no longer subject to China income tax examinations by tax authorities for tax years before 2007. With respect to state and local jurisdictions and countries outside of the U.S., with limited exceptions, we are no longer subject to income tax audits for years before 2012. Although the outcome of tax audits is always uncertain, we believe that adequate amounts of tax, interest and penalties, if any, have been provided for in our reserve for any adjustments that may result from future tax audits. We recognize accrued interest and penalties, if any, related to unrecognized tax benefits in interest expense. We had an immaterial amount of accrued interest and penalties at December 31, 2017, 2016 and 2015.

Deferred Taxes

The table below sets forth our deferred tax assets and liabilities as of December 31, 2017 and 2016:

	2017			2016
Deferred tax assets
Inventory cost	$	8,000		$	6,923
Accrued expenses and accounts receivable		690			2,112
Foreign tax credits		10,626			19,610
Research and development tax credits		15,828			13,633
Net operating loss carryforwards		5,392			37,379
Accrued pension		5,428			5,494
Share based compensation and others		12,443			16,992
		58,407			102,143
Valuation allowances		(22,560	)		(32,082	)
Total deferred tax assets, non-current		35,847			70,061
Deferred tax liabilities
Plant, equipment and intangible assets		(17,278	)		(28,639	)
Total deferred tax liabilities, non-current		(17,278	)		(28,639	)
Net deferred tax assets	$	18,569		$	41,422

We prospectively adopted ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists, (“ASU 2013-11”) effective in the first quarter of 2014. ASU No. 2013-11 provides that an entity is required to present an unrecognized tax benefit, or a portion of an unrecognized tax benefit, in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. The $15.4 million net deferred tax assets presented in the balance sheet as of December 31, 2017, is net of $3.2 million of unrecognized tax benefits. The $27.8 million net deferred tax asset presented on the balance sheet as of December 31, 2016, is net of $13.6 million of unrecognized tax benefits. The $41.4 million net deferred tax asset presented above is prior to the net balance sheet presentation required by ASU 2013-11.

We adopted ASU No. 2016-09, Compensation—Stock Compensation (Topic 718) Improvements to Employee Share-Based Payment Accounting, (“ASU 2016-09”) effective in the first quarter of 2017. The effect of the adoption related to the income tax components of ASU 2016-09 was an increase of $4.8 million to retained earnings and to deferred income tax assets, to record the tax benefit of the net operating loss carryforward resulting from excess tax deductions related to stock based compensation. ASU 2016-09 requires that the tax effects of differences between cumulative compensation expense recorded for financial statement purposes and available income tax deductions be recorded to income tax expense. We recorded a $1.5 million increase to income tax expense as a result of the application of ASU 2016-09 to stock based compensation vesting and exercise events that occurred during 2017.

At December 31, 2017, we had federal tax credit and research credit carryforwards of approximately $20 million and $7 million, respectively, which are available to offset future income tax liabilities. The federal tax credit carryforwards begin to expire in 2021 and the state tax credit carryforwards will begin to expire in 2020. We determined that it is more likely than not that a portion of our federal and state research credit carryforwards will expire before they are utilized. The valuation allowances recorded against the related deferred tax assets totaled $13 million and $22.4 million as of December 31, 2017 and 2016, respectively.

At December 31, 2017, we had state net operating loss (“NOL”) carryforwards of approximately $3 million, and foreign NOL carryforwards of $2 million which are available to offset future taxable income. The U.S. state NOL carryforwards will begin to expire in 2018. We determined that it is more likely than not that the U.S. state NOL carryforwards will expire before they are fully utilized and recorded a full valuation allowance on the related deferred tax assets. The foreign NOL carryforwards will begin to expire in 2020. We determined that it is more likely than not that a portion of the foreign NOL carryforwards will expire before they are fully utilized. The valuation allowances recorded against the related deferred tax assets totaled $5 million and $5.9 million as of December 31, 2017 and 2016, respectively.

Supplemental Information

Our undistributed foreign earnings continue to be indefinitely reinvested in foreign operations, with limited exceptions related to earnings of European subsidiaries. As of December 31, 2017, we had undistributed earnings from non-U.S. operations of approximately $770 million (including approximately $51 million of restricted earnings, which are not available for dividends). Undistributed earnings of our China subsidiaries comprise $429 million of this total. Additional Chinese withholding taxes of approximately $42 million would be required should the $429 million of such earnings be distributed out of China as dividends.

The impact of tax holidays decreased our tax expense by approximately $3.7 million, $7.3 million and $2.9 million for the years ended December 31, 2017, 2016 and 2015, respectively. The benefit of the tax holidays on basic and diluted earnings per share was $0.08, $0.15 and $0.06 for the twelve months ended December 31, 2017, 2016 and 2015, respectively.

Employee Benefit Plans

12 Months Ended

Dec. 31, 2017

Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plans

NOTE 12 – EMPLOYEE BENEFIT PLANS

Defined Benefit Plan

In connection with the Zetex acquisition, we adopted a contributory defined benefit plan that covers certain employees in the U.K. The defined benefit plan is closed to new entrants and frozen with respect to future benefit accruals. The retirement benefit is based on the final average compensation and service of each eligible employee. We determined the fair value of the defined benefit plan assets and utilize an annual measurement date of December 31. At subsequent measurement dates, defined benefit plan assets will be determined based on fair value. Defined benefit plan assets consist of a diverse range of listed and unlisted securities including corporate bonds and mutual funds and are denominated in the currency in which the benefits will be paid and that have terms to maturity approximating the terms of the related pension liability. The net pension and supplemental retirement benefit obligations and the related periodic costs are based on, among other things, assumptions of the discount rate, estimated return on plan assets and mortality rates. These obligations and related periodic costs are measured using actuarial techniques and assumptions. The projected unit credit method is the actuarial cost method used to compute the pension liabilities and related expenses. All unrecognized actuarial gains and losses, prior service costs and accumulated other comprehensive income are eliminated and the balance sheet liability is set equal to the funded status of the defined benefit plan at acquisition date.

The table below sets forth net periodic benefit costs of the plan for the years ended December 31, 2017 and 2016:

	Defined Benefit Plan

	2017			2016
Components of net periodic benefit cost:
Service cost	$	258		$	270
Interest cost		4,228			5,151
Recognized actuarial loss		1,325			993
Expected return on plan assets		(6,506	)		(6,210	)
Net periodic benefit cost	$	(695	)	$	204

The table below sets forth the benefit obligation, the fair value of plan assets, and the funded status as of December 31:

	Defined Benefit Plan

	2017			2016
Change in benefit obligation:
Beginning balance	$	146,801		$	145,019
Service cost		258			270
Interest cost		4,228			5,151
Actuarial loss		4,910			29,793
Benefits paid		(4,313	)		(6,816	)
Currency changes		14,179			(26,616	)
Benefit obligation at December 31	$	166,063		$	146,801

Change in plan assets:
Beginning balance - fair value	$	118,658		$	116,386
Employer contribution		2,974			2,105
Actual return on plan assets		5,454			28,422
Benefits paid		(4,313	)		(6,816	)
Currency changes		11,461			(21,439	)
Fair value of plan assets at December 31	$	134,234		$	118,658
Underfunded status at December 31	$	(31,829	)	$	(28,143	)

Based on an actuarial study performed as of December 31, 2017, the plan is underfunded by approximately $31.8 million and the liability is reflected in our consolidated balance sheets as a noncurrent liability and the amount recognized in accumulated other comprehensive loss was approximately $44.0 million.

We apply the “10% corridor” approach to amortize unrecognized actuarial gains (losses). Under this approach, only actuarial gains (losses) that exceed 10% of the greater of the projected benefit obligation or the market-related value of the plan assets are amortized. For the twelve months ended December 31, 2017, the plan’s total recognized loss increased by approximately $4.8 million. The variance between the actual and expected return to plan assets during 2017 decreased the total unrecognized net loss by approximately $1.1 million. The total unrecognized net loss is more than 10% of the projected benefit obligation and 10% of the plan assets. Therefore, the excess amount will be amortized over the average term to retirement of plan participants not yet in receipt of pension, which as of December 31, 2017 the average term was approximately 13 years. The following weighted-average assumptions were used to determine net periodic benefit costs for the twelve months ended December 31:

	2017		2016
Discount rate		2.8%	2.8%
Expected long-term return on plan assets		5.4%	5.4%

The following weighted-average assumption was used to determine the benefit obligations at December 31:

	2017			2016
Discount rate	2.6%			2.8%

The expected long-term return on plan assets was determined based on historical and expected future returns of the various asset classes. The plan’s investment policy includes a mandate to diversify assets and invest in a variety of asset classes to achieve its expected long-term return and is currently invested in a variety of funds representing most standard equity and debt security classes. Trustees of the plan may make changes at any time. The table below sets forth the plan asset allocations of the assets in the plan and expected long-term return by asset category:

Asset category	Expected long-term return			Asset allocation
Growth assets		7.7	%		64	%
Hedging assets		1.8	%		34	%
Cash		0.5	%		2	%
Total		5.5	%		100	%

Benefit plan payments are primarily made from funded benefit plan trusts and current assets. The table below sets forth the expected future benefit payments, including future benefit accrual, as of December 31, 2017:

2018	$	3,845
2019		3,998
2020		4,376
2021		4,871
2022		5,267
2023-2026		24,455

We adopted a payment plan with the trustees of the defined benefit plan, in which we would make annual contributions each year through 2030, of approximately GBP 2 million (approximately $2.8 million based on a GBP:USD exchange rate of 1.4). The annual contributions were expected to meet the deficit disclosed in the plan as of April 5, 2013 by December 31, 2030. The trustees are required to review the funding position every three years, and a further review was carried out as of April 5, 2016. The outcome of the review, as agreed with the trustees during the first quarter of 2017, was that contributions would continue at the existing level until December 31, 2029.

Our overall defined benefit plan investment strategy is to achieve a mix of investments for long-term growth and for near-term benefit payments with a wide diversification of asset types and fund strategies. The target allocations for plan assets are 48% equity securities, 40% corporate bonds and government securities, and 12% to absolute return funds. Equity securities primarily include investments in large-cap and mid-cap companies primarily located in the U.K. Fixed income securities include corporate bonds of companies from diversified industries, and U.K. government bonds. The absolute return fund is mainly invested in a mixture of equities and bonds.

The plan’s trustees appoint fund managers to carry out all the day-to-day functions relating to the management of the fund and its administration. The fund managers must invest their portion of the plan’s assets in accordance with their investment manager agreement agreed by the trustees. The trustees are responsible for agreeing these investment manager agreements and for deciding on the portion of the plan’s assets that will be invested with each fund manager. When making decisions, the trustees take advice from experts including the plan’s actuary and also have the option to consult with the Company.

The following table summarizes the major categories of the plan assets:

December 31, 2017
Asset category	Level 1		Level 2		Level 3		Total
Cash and cash equivalents	$	2,182	$	4,915	$	-	$	7,097
Equity securities:
U.K.		-		2,787		-		2,787
North America		-		16,082		-		16,082
Europe (excluding U.K.)		-		5,713		-		5,713
Japan		-		2,703		-		2,703
Pacific Basin (excluding Japan)		-		1,372		-		1,372
Emerging markets		-		4,448		-		4,448
Fixed income securities:
Corporate bonds		-		3,682		-		3,682
Others		-		5,731		-		5,731
Index linked securities:
Others		-		203		-		203
Other types of investments:
Absolute return funds		-		1,291		-		1,291
Hedge funds		-		27,355		-		27,355
Development REITS		-		6,004		-		6,004
Insurance linked securities		-		4,117		-		4,117
Liability driven investments		-		45,450		-		45,450
Other		-		199		-		199
Total	$	2,182	$	132,052	$	-	$	134,234

Fair value is taken to mean the bid value of securities, as supplied by the fund managers. All the plan’s securities are publically traded and highly liquid. The plan does not hold any Level 3 securities. See Note 2 for additional information regarding fair value and Levels 1, 2 and 3.

The investment manager agreements require the fund managers to invest in a diverse range of stocks and bonds across each particular asset class. The stocks held by the plan in a particular asset class should therefore match closely the underlying stocks in the relevant index. We believe that this leads to minimal concentration of risk within each asset class; although we recognize that some asset classes are inherently more risky than others.

We also have pension plans in Asia for which the benefit obligation, fair value of the plan assets and the funded status amounts are immaterial and therefore, not included in the amounts or assumptions above.

401(k) Retirement Plan

We maintain a 401(k) retirement plan (“the Plan”) for the benefit of qualified employees at our U.S. locations. Employees who participate may elect to make salary deferral contributions to the Plan up to 100% of the employees’ eligible payroll subject to annual Internal Revenue Code maximum limitations. We currently make a matching contribution of $1 for every $2 contributed by the participant up to 6% (3% maximum matching) of the participant’s eligible payroll, which vests over an initial four years. In addition, we may make a discretionary contribution to the entire qualified employee pool, in accordance with the Plan.

As stipulated by the regulations of China, we maintain a retirement plan pursuant to the local municipal government for the employees in China. We are required to make contributions to the retirement plan at a rate between 10% and 22% of the employee’s eligible payroll. Pursuant to the Taiwan Labor Standard Law and Factory Law, we maintain a retirement plan for the employees in Taiwan, whereby we make contributions at a rate of 6% of the employee’s eligible payroll.

For the years ended December 31, 2017, 2016 and 2015, total amounts expensed under these plans were approximately $14.8 million, $13.9 million and $14.0 million, respectively.

Deferred Compensation Plan

We maintain a Non-Qualified Deferred Compensation Plan (the “Deferred Compensation Plan”) for executive officers, key employees and members of the Board of Directors (the “Board”). The Deferred Compensation Plan allows eligible participants to defer the receipt of eligible compensation, including equity awards, until designated future dates. We offset our obligations under the Deferred Compensation Plan by investing in the actual underlying investments. These investments are classified as trading securities and are carried at fair value. At December 31, 2017, these investments totaled approximately $8.8 million. All gains and losses in these investments are materially offset by corresponding gains and losses in the deferred compensation plan liabilities.

Share-Based Compensation

12 Months Ended

Dec. 31, 2017

Share Based Compensation [Abstract]

Share-Based Compensation

NOTE 13 - SHARE-BASED COMPENSATION

The table below sets forth the line items where share-based compensation expense was recorded for the twelve months ended December 31, 2017, 2016 and 2015:

	2017		2016		2015
Cost of goods sold	$	645	$	775	$	716
Selling, general and administrative expense		15,130		10,567		16,228
Research and development expense		2,834		2,687		2,026
Total share-based compensation expense	$	18,609	$	14,029	$	18,970

The table below sets forth share-based compensation expense by type for the twelve months ended December 31, 2017, 2016 and 2015:

	2017		2016		2015
Stock options	$	934	$	1,511	$	2,516
Share grants		17,675		12,518		16,454
Total share-based compensation expense	$	18,609	$	14,029	$	18,970

In 2016, we recorded a $2.7 million reversal decrease of previously recorded expense related to performance grants. In 2015, we recorded $4.0 million in restricted stock expense related to Diodes restricted stock grants issued as replacement for unvested Pericom employee awards outstanding at the date of the acquisition.

In May 2013, our stockholders approved our 2013 Equity Incentive Plan (“2013 Plan”). Since the approval of the 2013 Plan, all stock options are granted under the 2013 Plan, and we will not grant any further stock options under our 2001 Plan. Stock options under the 2013 Plan generally vest in equal annual installments over a four-year period and expire eight years after the grant date. The number of shares originally authorized to be awarded under the 2013 Plan was 6 million shares. In May 2017, our stockholders approved an amendment to the 2013 Plan, authorizing and additional 6 million shares to be awarded, bringing the total shares authorized to be awarded under the 2013 Plan to 12 million shares.

Share-based compensation expense for stock options granted in previous years was calculated on the date of grant using the Black-Scholes-Merton option-pricing model. No stock options were granted in any of the periods presented.

Total cash received from option exercises was approximately $13.6 million, $0.1 million and $10.2 million during 2017, 2016 and 2015, respectively.

At December 31, 2017, unrecognized compensation expense related to unvested options, net of estimated forfeitures, was approximately $0.3 million. The weighted average period over which share-based compensation expense related to these options will be recognized is less than 1 year.

The table below sets forth a summary of activity in our stock option plans:

Stock Options	Shares			Weighted Average Exercise Price ($)		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value
Outstanding at December 31, 2014		2,736			21.26
Granted		-			-
Exercised		(653	)		15.63
Forfeited or expired		(20	)		22.91
Outstanding at December 31, 2015		2,063			23.03
Granted		-			-
Exercised		(7	)		18.48
Forfeited or expired		(223	)		22.75
Outstanding at December 31, 2016		1,833			23.08
Granted		-			-
Exercised		(581	)		23.42
Forfeited or expired		(24	)		26.87
Outstanding at December 31, 2017		1,228			22.85		3.1	$	7,298
Exercisable at December 31, 2017		1,186			22.67		3.1	$	7,266

The table below sets forth information about stock options outstanding at December 31, 2017:

Plan	Range of exercise prices		Number outstanding		Weighted average remaining contractual life (years)		Weighted average exercise price
2001 Plan	$	15.05-29.21		917		2.9	$	21.90
2013 Plan	$	23.35-27.92		311		3.9	$	25.29

Share Grants—Restricted stock awards and restricted stock units generally vest in equal annual installments over a four-year period. Since the approval of the 2013 Plan, all new grants are granted under the 2013 Plan, and we will not grant any further grants under our 2001 Plan.

The table below sets forth a summary of our non-vested share grants in 2017, 2016 and 2015:

Restricted Stock Grants	Shares			Weighted Average Grant Date Fair Value ($)		Aggregate Intrinsic Value
Nonvested at December 31, 2014		1,535			23.32
Granted		1,557			22.46
Vested		(370	)		25.02
Forfeited		(43	)		26.08
Nonvested at December 31, 2015		2,679			23.51
Granted		880			18.63
Vested		(877	)		18.92
Forfeited		(62	)		20.80
Nonvested at December 31, 2016		2,620			21.31
Granted		746			25.23
Vested		(645	)		21.89
Forfeited		(441	)		22.31
Nonvested at December 31, 2017		2,280			22.24	$	65,357

During 2017 the Company modified a performance-based award previously granted to our Chief Executive Officer. The effect was to replace a performance-based grant covering 700,000 shares of the Company’s common stock with a performance-based grant covering 62,905 shares of the Company’s common stock and a restricted stock grant covering 62,905 of the Company’s common stock. If certain performance criteria are met for the performance-based grant, Dr. Lu will receive 200% of that award or 125,810 shares. The incremental expense if Dr. Lu received 200% of the performance-based grant award is approximately $3.3 million. The incremental expense of the restricted stock grant is approximately $1.7 million.

Included in the restricted stock grant for 2015 were 724,000 shares granted to Pericom employees. During 2016, the Company paid $2.5 million in taxes related to the net share settlement on shares of stock that vested for Pericom employees. .

The total unrecognized share-based compensation expense as of December 31, 2017 was approximately $32.4 million, relating to restricted stock awards, which was expected to be recognized over a weighted average period of approximately 2.4 years.

Our Chief Executive Officer has a grant of 600,000 performance-based stock units that vest upon the Company reaching $1.0 billion in revenue. Based on the Company reaching approximately $1.1 billion in revenue in 2017, our Chief Executive Officer’s grant of 600,000 performance-based stock units will be released to the Chief Executive Officer, upon filing of the Company’s Annual Report on Form 10-K, in February 2018. The expense related to the 600,000 performance-based units was all recognized in previous periods.

Related Party Transactions

12 Months Ended

Dec. 31, 2017

Related Party Transactions

NOTE 14 – RELATED PARTY TRANSACTIONS

We conduct business with a related party company, Lite-On Semiconductor Corporation, and its subsidiaries and affiliates (“LSC”), and Nuvoton Technology Corporation and its subsidiaries and affiliates (collectively, “Nuvoton”). LSC is our largest stockholder, owning approximately 16% of our outstanding Common Stock as of December 31, 2017, and is a member of the Lite-On Group of companies. We sold products to LSC totaling less than 1% of our net sales for the years ended December 31, 2017, 2016 and 2015, respectively. Raymond Soong, the Chairman of the Board of Directors, is the Chairman of LSC, and is the Chairman of Lite-On Technology Corporation (“LTC”), a significant shareholder of LSC. C.H. Chen, our former President and Chief Executive Officer and currently the Vice Chairman of the Board of Directors, is also Vice Chairman of LSC and a board member of LTC. Dr. Keh-Shew Lu, our President and Chief Executive Officer and a member of our Board of Directors, is a board member of LTC, and a board member of Nuvoton. L.P. Hsu, a former member of our Board of Directors serves as a consultant to LTC, and is a supervisor of the board of Nuvoton. We consider our relationships with LSC, a member of the Lite-On Group of companies, and Nuvoton to be mutually beneficial and we plan to continue our strategic alliance with LSC and Nuvoton. We purchase wafers from Nuvoton for use in our production process.

We also conduct business with Keylink International (B.V.I.) Inc. and its subsidiaries and affiliates (“Keylink”). Keylink is our 5% partner in our Shanghai assembly and test facilities. We sell products to, and purchase inventory from, companies owned by Keylink. We sold products to companies owned by Keylink, totaling approximately 1% of net sales for each of the years ended December 31, 2017, 2016 and 2015. In addition, our subsidiaries in China lease their manufacturing facilities in Shanghai from, and subcontract a portion of our manufacturing process (metal plating and environmental services) to, Keylink. We also pay a consulting fee to Keylink. The aggregate amounts paid to Keylink for the years ended December 31, 2017, 2016 and 2015 were approximately $17.1 million, $16.1 million and $17.9 million, respectively. In addition, Chengdu Ya Guang Electronic Company Limited (“Ya Guang”) is our 2% partner in one of our Chengdu assembly and test facilities and our 5% partner in our two Chengdu assembly and test facilities; however, we have no material transactions with Ya Guang. We also purchase materials from Jiyuan Crystal Photoelectric Frequency Technology Ltd. (“JCP”) an FCP manufacturing company in which we have made an equity investment and account for using the equity method of accounting.

The Audit Committee of the Board reviews all related party transactions for potential conflict of interest situations on an ongoing basis, all in accordance with such procedures as the Audit Committee may adopt from time to time.

The table below sets forth net sales and purchases from related parties for the twelve months ended December 31:

	2017		2016		2015
LSC
Net sales	$	1,406	$	852	$	588
Purchases	$	24,313	$	21,936	$	22,378
Keylink
Net sales	$	8,856	$	9,125	$	9,749
Purchases	$	3,827	$	5,054	$	6,272
Nuvoton
Purchases	$	11,407	$	10,386	$	12,598
JCP
Purchases	$	1,105	$	826	N/A

The table below sets forth accounts receivable from and accounts payable to related parties at December 31:

	2017		2016
LSC
Accounts receivable	$	342	$	301
Accounts payable	$	3,308	$	4,333
Keylink
Accounts receivable	$	4,089	$	5,394
Accounts payable	$	5,016	$	4,295
Nuvoton
Accounts payable	$	1,121	$	950
JCP
Accounts payable	$	317	$	263

Segment Information and Enterprise-Wide Disclosures

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Segment Information and Enterprise-Wide Disclosures

NOTE 15 – SEGMENT INFORMATION AND ENTERPRISE-WIDE DISCLOSURES

An operating segment is defined as a component of an enterprise about which separate financial information is available that is evaluated regularly by the chief decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. Our chief operating decision maker is our CEO. For financial reporting purposes, we operate in a single segment, standard semiconductor products, through our various manufacturing and distribution facilities.

Our primary operations include the operations in Asia, North America and Europe. The table below sets forth net sales by geographic areas based on the location of subsidiaries producing the net sales:

2017	Asia			North America			Europe			Consolidated
Total sales	$	968,720		$	171,964		$	175,004		$	1,315,688
Inter-company sales		(128,924	)		(71,608	)		(60,952	)		(261,484	)
Net sales	$	839,796		$	100,356		$	114,052		$	1,054,204

Property, plant and equipment	$	390,850		$	44,523		$	23,796		$	459,169
Assets	$	1,061,686		$	230,997		$	195,990		$	1,488,673

2016	Asia			North America			Europe			Consolidated
Total sales	$	895,608		$	109,442		$	157,343		$	1,162,393
Inter-company sales		(137,959	)		(22,034	)		(60,238	)		(220,231	)
Net sales	$	757,649		$	87,408		$	97,105		$	942,162

Property, plant and equipment	$	329,587		$	57,145		$	15,256		$	401,988
Assets	$	948,923		$	400,472		$	179,157		$	1,528,552

2015	Asia			North America			Europe			Consolidated
Total sales	$	793,960		$	143,800		$	164,304		$	1,102,064
Inter-company sales		(118,415	)		(60,882	)		(73,863	)		(253,160	)
Net sales	$	675,545		$	82,918		$	90,441		$	848,904

Property, plant and equipment	$	362,186		$	58,152		$	19,002		$	439,340
Assets	$	969,352		$	463,967		$	165,508		$	1,598,827

The accounting policies of the operating entities are the same as those described in the summary of significant accounting policies.

The table below sets forth net sales by country. We report net sales based on “shipped to” customer locations as we believe this best represents where our customers’ business activities occur. “All others” represents countries with less than 3% of total net sales each.

			% of Total
2017	Net Sales		Net Sales
China	$	593,098		56	%
U.S.		86,276		8	%
Korea		65,849		6	%
Germany		74,303		7	%
Singapore		58,570		6	%
Taiwan		67,399		6	%
All others		108,709		11	%
Total	$	1,054,204		100	%

			% of Total
2016	Net Sales		Net Sales
China	$	548,015		58	%
U.S.		79,869		8	%
Korea		60,672		6	%
Germany		61,415		7	%
Singapore		48,464		5	%
Taiwan		59,087		6	%
All others		84,640		10	%
Total	$	942,162		100	%

			% of Total
2015	Net Sales		Net Sales
China	$	507,783		60	%
U.S.		76,870		9	%
Korea		66,605		8	%
Germany		57,036		7	%
Singapore		51,742		6	%
Taiwan		30,127		4	%
All others		58,741		6	%
Total	$	848,904		100	%

Major customers – One customer accounted for 10% or more of our net sales in 2017, but not 10% of our outstanding accounts receivable at December 31, 2017. No customers accounted for 10% or more of our net sales in 2016 or 2015.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

NOTE 16 – COMMITMENTS AND CONTINGENCIES

Operating leases – We lease offices, manufacturing plants, equipment, vehicles and warehouses under operating lease agreements expiring through December 2024. Rental expense amounted to approximately $10.4 million, $10.5 million and $10.1 million for the years ended December 31, 2017, 2016 and 2015, respectively. We do not have purchase options related to the operating lease agreements. The table below sets forth the approximate amount for future minimum lease payments under non-cancelable operating leases at December 31, 2017:

2018	$	9,187
2019		7,662
2020		5,642
2021		3,931
2022		3,365
Thereafter		2,068
	$	31,855

In addition, we have the following land right leases. None of the leases requires a rental payment.

Location	Term (years)	Expiration Date
Chengdu, China	50	2061
Shanghai, China	50	2056
Shandong, China	50	2058
Shanghai, China	50	2058
Yangzhou, China	50	2065

Purchase commitments – We have entered into non-cancelable purchase contracts for capital expenditures, primarily for manufacturing equipment, for approximately $23.5 million at December 31, 2017. In addition to these purchase commitments, we have equity investment obligations for our Chengdu facilities of $50 million, $25 million and $25 million for 2018, 2019 and 2020, respectively, and capital investment obligations of $62 million, $25 million and $29 million for 2018, 2019 and 2020, respectively.

Contingencies - From time to time, we are involved in various legal proceedings that arise in the normal course of business. While we intend to defend any lawsuit vigorously, we presently believe that the ultimate outcome of any current pending legal proceeding will not have any material adverse effect on our financial position, cash flows or operating results. However, litigation is subject to inherent uncertainties, and unfavorable rulings could occur. An unfavorable ruling could include monetary damages, which could impact on our business and operating results for the period in which the ruling occurs or future periods. Based on information available, we evaluate the likelihood of potential outcomes. We record the appropriate liability when the amount is deemed probable and reasonably estimable. In addition, we do not accrue for estimated legal fees and other directly related costs as they are expensed as incurred. The Company is not currently a party to any pending litigation that the Company considers material.

Derivative Financial Instruments

12 Months Ended

Dec. 31, 2017

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivative Financial Instruments

NOTE 17 – DERIVATIVE FINANCIAL INSTRUMENTS

In accordance with ASC 815 we recognize derivative instruments on our balance sheet, and we measure them at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether we have elected to designate the derivative as being in a hedging relationship, and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivative instruments that are designated, and qualify as hedges of the exposure to changes in the fair value are considered fair value hedges. Derivative instruments that are designated, and qualify as hedges of the exposure to variability in expected future cash flows are considered cash flow hedges. Derivative instruments may also be designated as hedges of the foreign currency exposure of a net investment in a foreign operation. We currently only utilize cash flow hedges and do not use derivatives for trading or speculative purposes.

Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge, or the earnings effect of the hedged forecasted transactions in a cash flow hedge. We may enter into derivative contracts that are intended to economically hedge certain risks, even though we elect not to apply hedge accounting under ASC 815. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in the consolidated statements of income. Specific information about the valuations of derivatives is described in Note 1 and classification of derivatives in the fair value hierarchy is described in Note 2. Currently our interest rate swaps and interest rate collars are designated as hedges while our foreign exchange contracts are not designated as hedges.

The effective portion of changes in the fair value of derivatives designated and qualifying as cash flow hedges is recorded in accumulated other comprehensive loss and is subsequently reclassified into earnings in the period in which the hedged forecasted transaction affects earnings.

Certain of the Company's agreements with its derivative counterparties contain provisions where if certain merger activity, a change of control, or a capital structure change occurs that materially changes the Company's creditworthiness in an adverse manner, the Company’s counterparty may have the right to terminate any derivative transactions under such agreement.

The company has agreements with each of its derivative counterparties that contain a provision where the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company's default on the indebtedness.

Hedges of Foreign Currency Risk

We are exposed to fluctuations in various foreign currencies against our different functional currencies. We use foreign currency forward agreements to manage this exposure. At December 31, 2017 we had outstanding foreign currency forward contracts that are intended to preserve the economic value of foreign currency denominated monetary assets and liabilities; these instruments are not designated for hedge accounting treatment in accordance with ASC 815. There is no fair value of our foreign exchange hedges, therefore they are not recorded in our Consolidated Balance Sheets. As of December 31, 2017 and 2016 the total notional amounts of these foreign exchange contracts was $87.6 million and zero, respectively.

The table below sets forth outstanding foreign currency forward contracts at December 31, 2017:

Notional Amount		Effective Date	Maturity Date	Index*	Weighted Average Strike Rate	Cash Flow Hedge Designation
$	2,494	December 2017	December 2017	EUR/GPB	1.2009	Non-designated
	10,514	December 2017	December 2017	EUR/USD	1.2009	Non-designated
	10,612	December 2017	December 2017	GPB/USD	1.3541	Non-designated
	31,834	December 2017	December 2017	USD/CNY	6.5343	Non-designated
	1,594	December 2017	December 2017	USD/JPY	112.35	Non-designated
	30,594	December 2017	December 2017	USD/TWD	29.406	Non-designated

* EUR = Euro
GBP = British Pound Sterling
USD = United States Dollar
CNY = Chinese Yuan Renminbi
JPY = Japan Yen
TWD = Taiwan dollar

Hedges of Interest Rate Risk

The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps, including interest rate collars, as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount.

The table below sets forth information related to the number of and the notional amount of our interest rate related derivative instruments at December 31 2017 and December 31, 2016:

	Number of Instruments		Notional Amount
	2017	2016	2017		2016
Interest rate swaps and collars	14	6	$	220,000	$	150,000

The table below sets forth the fair value of the Company’s interest rate related derivative financial instruments as well as their classification on the Consolidated Balance Sheets as of December 31, 2017 and December 31, 2016:

	Fair Value
	Other Current Assets				Other Assets				Other Liabilities
	2017		2016		2017		2016		2017		2016
Interest rate swaps and collars	$	486	$	-	$	3,398	$	3,052	$	-	$	735

The tables below sets forth the effect of the Company’s derivative financial instruments on the Consolidated Statements of Income for the years ended December 31, 2017 and 2016:

Derivatives Designated as Hedging Instruments	Amount of Gain or (Loss) Recognized in OCI on Derivative				Location of Gain or (Loss) Reclassified from Accumulated OCI into Income	Amount of Gain or (Loss) Reclassified from Accumulated OCI into Net Income
	2017		2016			2017		2016
Interest rate swaps and collars	$	1,567	$	2,317	Interest expense	$	577	$	112

We estimate that $0.5 million of net derivative gains included in AOCI as of December 31, 2017 will be reclassified into earnings within the following 12 months. No gains or losses were reclassified from AOCI into earnings as a result of forecasted transactions that failed to occur during fiscal year 2017.

Derivatives Not Designated as Hedging Instruments	Amount of Gain or (Loss) Recognized in Net Income				Location of Gain or (Loss) Reclassified from Accumulated OCI into Income
	2017		2016
Foreign currency forward contracts	$	1,491	$	-	Foreign currency (loss) gain, net

There was no effect from derivative financial instruments on the Company’s Consolidated Statements of Operations for the twelve months ended December 31, 2015.

At December 31, 2017 and 2016, the fair value of derivatives in a net asset position, which includes accrued interest but excludes any adjustments for nonperformance risk, related to these agreements was $3.9 million and $2.3 million, respectively. As of December 31, 2017 and 2016, the Company had not posted any collateral related to these agreements.

Restructuring Costs

12 Months Ended

Dec. 31, 2017

Restructuring And Related Activities [Abstract]

Restructuring Costs

NOTE 18 – RESTRUCTURING COSTS

In February 2017, the Company announced its plan to transfer its wafer fabrication operation at KFAB to other Company-owned wafer fabrication plants and external foundries. The Company ceased production operations at KFAB late in third quarter 2017 and vacated and returned the premises in November 2017. Employees were provided retention and standard severance packages. During 2017 the Company received $6.5 million of insurance proceeds as a result of the fires sustained at the KFAB facility during 2016 of which $4.5 million is recorded in Cost of Goods Sold and $2.0 million is recorded in Other Income. There are outstanding insurance claims. Also during 2017, the Company recorded $1.9 million of asset impairment related to the shut-down of KFAB.

The table below sets forth the restructuring costs, recorded in restructuring expense in the Condensed Consolidated Statements of Operations, incurred during the twelve months ended December 31, 2017:


Early termination of supply contract	$	1,985
Asset retirement obligation		1,403
Retention cost		3,158
Cost of equipment relocation, shutdown cost and other		3,591
Total	$	10,137

The table below sets forth the costs accrued related to the KFAB restructuring:

	Early Contract Termination			Retention Costs			Equipment Relocation, Shutdown Cost and Other			Total
Beginning balance, January 1, 2017	$	-		$	-		$	-		$	-
Costs accrued		1,985			3,158			3,591			8,734
Restructuring costs paid		(1,985	)		(2,499	)		(2,946	)		(7,430	)
Balance at December 31, 2017	$	-		$	659		$	645		$	1,304

The Company will pay out the remaining accrued costs during the first quarter of 2018.

Based on continued negotiations with the landlord, we recorded an additional $1.4 million of asset retirement obligations related the KFAB restructuring. This asset retirement obligation is for the estimated amounts to be paid to contractors to remediate the KFAB facility upon vacating the property. The table below sets forth the asset retirement obligation related to the KFAB restructuring:

Asset retirement obligation, January 1, 2017	$	486
Accrual of additional asset retirement obligation		1,403
Amount paid		(1,500	)
Asset retirement obligation, December 31, 2017	$	389

In connection with the asset retirement obligation, the Company recorded amortization expense of the offsetting asset of $1.4 million for the twelve months ended December 31, 2017.

Business Combination

12 Months Ended

Dec. 31, 2017

Business Combinations [Abstract]

Business Combination

NOTE 19 – BUSINESS COMBINATION

Pericom Semiconductor Corporation

On November 24, 2015, we completed our acquisition of Pericom Semiconductor Corporation (“Pericom”) pursuant to the Agreement and Plan of Merger dated as of September 2, 2015 (the “Merger Agreement”), as amended on November 6, 2015, by Amendment No. 1 (the “Merger Agreement Amendment”). Under the Merger Agreement and the Merger Agreement Amendment and in accordance with the General Corporation Law of the State of California (1) PSI Merger Sub, Inc., a California corporation and wholly-owned subsidiary of the Company, was merged with and into Pericom, with Pericom continuing as the surviving corporation and a wholly-owned subsidiary of the Company, and (2) each outstanding share of common stock, without par value, of Pericom (other than shares owned by Pericom or certain of its affiliates or shares held by Pericom shareholders who have perfected their appraisal rights in accordance with applicable California law) was automatically converted into the right to receive $17.75 in cash per share, without interest. The aggregate consideration was approximately $403.2 million including the value of Pericom equity awards paid out or converted to Diodes equity awards pursuant to the Merger Agreement and Merger Agreement Amendment.

The table below sets forth the estimated purchase price and related costs for Pericom:

Cash consideration for shares outstanding	$	391,123
Cash consideration for vested stock awards, including taxes of $88		7,371
Value of Diodes stock to be issued in exchange for unvested Pericom employee stock awards.		4,680
Total purchase price	$	403,174

The results of operations of Pericom are included in our consolidated financial statements from November 24, 2015. The consolidated revenue and earnings of Pericom included in our consolidated financial statements for the twelve months ended December 31, 2015 was approximately $14.6 million and $(1.0) million, respectively, which include acquisition accounting adjustments. The purpose of the acquisition was to further our strategy of expanding market and growth opportunities through selected strategic acquisitions.

The table below sets for the unaudited pro forma consolidated results of operations for the twelve month ended December 31, 2015 as if the acquisition of Pericom had occurred at January 1, 2014:

	Twelve Months Ended
	December 31, 2015
Net revenues	$	960,019
Net income attributable to common stockholders	$	40,180
Earnings per share—Basic	$	0.82
Earnings per share—Diluted	$	0.80

The unaudited pro forma consolidated results of operations do not purport to be indicative of the results that would have been obtained if the above acquisition had actually occurred as of the dates indicated or of those results that may be obtained in the future. The unaudited proforma consolidated results for December 31, 2015, exclude $10.0 million of acquisition related costs and $8.0 million of costs from Diodes restricted stock grants and change-in-control agreements for Pericom employees, and include additional amortization and depreciation of $12.0 million, additional interest expense of $11.0 million and additional income tax expense of $1.0 million. These unaudited pro forma consolidated results of operations were derived, in part, from the historical consolidated financial statements of Pericom and other available information and assumptions believed to be reasonable under the circumstances. Pericom will be conformed to Diodes’ reporting calendar.

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2017

Selected Quarterly Financial Information [Abstract]

Selected Quarterly Financial Data

NOTE 20 – SELECTED QUARTERLY FINANCIAL DATA (Unaudited)


	1st Quarter			2nd Quarter		3rd Quarter		4th Quarter
2017
Net sales	$	236,303		$	264,224	$	285,247	$	268,430
Gross profit		73,911			90,139		96,347		96,379
Net income (loss) attributable to common shareholders		1,217			13,179		14,450		(30,651	)
Earnings (loss) per share attributable to common shareholders
Basic	$	0.03		$	0.27	$	0.29	$	(0.62	)
Diluted	$	0.02		$	0.26	$	0.29	$	(0.62	)


	1st Quarter			2nd Quarter		3rd Quarter		4th Quarter
2016
Net sales	$	222,738		$	236,645	$	250,694	$	232,085
Gross profit		64,220			74,817		80,623		67,263
(Loss) net income attributable to common shareholders		(1,733	)		5,752		10,648		1,268
(Loss) earnings per share attributable to common shareholders
Basic	$	(0.04	)	$	0.12	$	0.22	$	0.07
Diluted	$	(0.04	)	$	0.12	$	0.21	$	0.07

Note: The sum of the quarterly earnings per share may not equal the full year amount, as the computations of the weighted average number of common shares outstanding for each quarter and for the full year are performed independently.

Summary of Operations and Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Nature of Operations

Principles of consolidation

Use of estimates

Revenue recognition

Product warranty

Product warranty – We generally warrant our products for a period of one year from the date of sale. Historically, warranty expense has not been material.

Cash, cash equivalents, and short-term investments

Allowance for doubtful accounts

Inventories

Property, plant and equipment

Goodwill and other indefinite lived intangible assets

Impairment of long-lived assets

Business combinations

Income taxes

Research and development costs

Shipping and handling costs

Concentration of credit risk

Derivative instruments and hedging activities

Valuation of financial instruments

Earnings per share

	Twelve Months Ended December 31,
	2017			2016		2015
Earnings (numerator)
Net (loss) income attributable to common stockholders	$	(1,805	)	$	15,935	$	24,274

Shares (denominator)
Weighted average common shares outstanding (basic)		48,824			48,597		48,210
Dilutive effect of stock options and stock awards outstanding		-			1,192		1,290
Adjusted weighted average common shares outstanding (diluted)		48,824			49,789		49,500

(Loss) earnings per share attributable to common stockholders
Basic	$	(0.04	)	$	0.33	$	0.50
Diluted	$	(0.04	)	$	0.32	$	0.49

Share-based compensation

Treasury stock

Functional currencies and foreign currency translation

Defined benefit plan

Investment in joint ventures

Noncontrolling interest

Contingencies

Comprehensive income (loss)

There is no income tax expense or benefit associated with each component of comprehensive income. As of December 31, the accumulated balance for each component of comprehensive income is as follows:

	2017			2016
Unrealized foreign currency losses	$	(42,010	)	$	(75,075	)
Unrealized gain on interest rate swap, net of tax	$	2,524		$	1,506
Unrealized loss on defined benefit plan	$	(43,994	)	$	(39,097	)

Reclassifications

Reclassifications – Certain immaterial amounts from prior periods have been reclassified to conform to the current years’ presentation.

Recently accounting pronouncements

•

Recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that the entity otherwise would have recognized is one year or less;

•

Use the portfolio approach, in estimating variable consideration, which specifies the accounting for an individual contract with a customer;

•

Continue to expense shipping and handling as fulfillment activities; and

•

Continue to exclude sales taxes from the transaction price.

Summary of Operations and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

	Twelve Months Ended December 31,
	2017			2016		2015
Earnings (numerator)
Net (loss) income attributable to common stockholders	$	(1,805	)	$	15,935	$	24,274

Shares (denominator)
Weighted average common shares outstanding (basic)		48,824			48,597		48,210
Dilutive effect of stock options and stock awards outstanding		-			1,192		1,290
Adjusted weighted average common shares outstanding (diluted)		48,824			49,789		49,500

(Loss) earnings per share attributable to common stockholders
Basic	$	(0.04	)	$	0.33	$	0.50
Diluted	$	(0.04	)	$	0.32	$	0.49

Component of Comprehensive Income

There is no income tax expense or benefit associated with each component of comprehensive income. As of December 31, the accumulated balance for each component of comprehensive income is as follows:

	2017			2016
Unrealized foreign currency losses	$	(42,010	)	$	(75,075	)
Unrealized gain on interest rate swap, net of tax	$	2,524		$	1,506
Unrealized loss on defined benefit plan	$	(43,994	)	$	(39,097	)

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Financial Assets At Fair Value

Financial assets and liabilities carried at fair value as of December 31, 2017 are classified in the following table:

Description	Fair Market Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Changes in Fair Values Included in Current Period Earnings
Short-term investments	$	4,558	$	2,586	$	1,972	$	-	$	-
Interest rate swaps and collars		3,884		-		3,884		-		-

Financial assets and liabilities carried at fair value as of December 31, 2016 are classified in the following table:

Description	Fair Market Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Changes in Fair Values Included in Current Period Earnings
Short-term investments	$	29,842	$	2,737	$	27,105	$	-	$	-
Interest rate swap assets		2,317		-		2,317		-		-

Inventories (Tables)

12 Months Ended

Dec. 31, 2017

Inventory Disclosure [Abstract]

Schedule of Inventory Current

Inventories, stated at the lower of cost or market value, at December 31 were:

	2017		2016
Finished goods	$	81,194	$	66,930
Work-in-progress		52,578		45,408
Raw materials		82,734		81,145
	$	216,506	$	193,483

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Schedule of Property Plant And Equipment

	2017			2016
Buildings and leasehold improvements	$	203,054		$	192,290
Machinery and equipment		774,138			685,249
		977,192			877,539
Less: Accumulated depreciation and amortization		(581,753	)		(535,407	)
		395,439			342,132
Construction in-progress		22,446			24,049
Land		41,284			35,807
	$	459,169		$	401,988

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Intangible Assets Net Excluding Goodwill [Abstract]

Schedule of Intangible Assets

Intangible assets subject to amortization at December 31 were as follows:

December 31, 2017
Intangible Assets	Useful life	Gross Carrying Amount		Accumulated Amortization			Currency Exchange			Net
Amortized intangible assets
Patents	5-15 years	$	11,823	$	(9,154	)	$	(242	)	$	2,427
Software license	3 years		1,212		(1,149	)		(63	)		-
Developed product technology	2-10 years		154,795		(53,925	)		(6,219	)		94,651
Customer relationships	12 years		62,093		(19,319	)		(1,650	)		41,124
Other	4 years		4,610		(4,512	)		(75	)		23
Total amortized intangible assets			234,533		(88,059	)		(8,249	)		138,225
Intangible assets with indefinite lives
In process research and development	Indefinite		8,914		-			-			8,914
Trademarks and trade names	Indefinite		10,303		-			(997	)		9,306
Total Intangible assets with indefinite lives			19,217		-			(997	)		18,220
Total intangible assets		$	253,750	$	(88,059	)	$	(9,246	)	$	156,445

December 31, 2016
Intangible Assets	Useful life	Gross Carrying Amount		Accumulated Amortization			Currency Exchange			Net
Amortized intangible assets
Patents	5-15 years	$	11,823	$	(8,431	)	$	(255	)	$	3,137
Software license	3 years		1,212		(1,149	)		(63	)		-
Developed product technology	2-10 years		153,009		(41,416	)		(6,299	)		105,294
Customer relationships	12 years		62,093		(13,915	)		(1,750	)		46,428
Other	4 years		4,610		(4,336	)		(75	)		199
Total amortized intangible assets			232,747		(69,247	)		(8,442	)		155,058
Intangible assets with indefinite lives
In process research and development	Indefinite		10,700		-			-			10,700
Trademarks and trade names	Indefinite		10,303		-			(1,185	)		9,118
Total Intangible assets with indefinite lives			21,003		-			(1,185	)		19,818
Total intangible assets		$	253,750	$	(69,247	)	$	(9,627	)	$	174,876

Schedule of Expected Amortization Expense

Amortization of intangible assets is as follows:

2018	$	18,003
2019		17,498
2020		15,472
2021		14,775
2022		13,956
2023 and thereafter		58,521
Total	$	138,225

Goodwill (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Changes in Goodwill

Changes in goodwill for the years ended December 31 were as follows:

Balance at December 31, 2015		132,913
Pericom measurement period adjustment		2,741
Foreign currency translation adjustment		(6,242	)
Balance at December 31, 2016		129,412
Foreign currency translation adjustment		4,775
Balance at December 31, 2017	$	134,187

Bank Credit Agreements and Other Short-Term and Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2017

Long Term Debt By Current And Noncurrent [Abstract]

Schedule of Debt

Long-term debt balances as of December 31, consist of the following:

	2017			2016
Notes payable to Taiwan bank, original principal amount of TWD 132 million, variable interest (approximately 1.7% as of December 31, 2017), matures July 6, 2021.	$	1,271		$	1,466
Term loan and revolver		268,812			428,375
Total long-term debt		270,083			429,841
Less: Current portion		(20,636	)		(14,356	)
Less: Unamortized debt issuance costs		(1,955	)		(2,359	)
Long-term debt, net of current portion	$	247,492		$	413,126

Schedule of Maturities of Long Term Debt

The table below sets forth the annual contractual maturities of long-term debt at December 31, 2017:

2018	$	20,636
2019		26,892
2020		33,147
2021		189,408
Total long-term debt	$	270,083

Capital Lease Obligations (Tables)

12 Months Ended

Dec. 31, 2017

Capital Lease Obligations [Abstract]

Summary of Future Minimum Lease Payments under Capital Lease Agreements

Future minimum lease payments under capital lease agreements are summarized as follows:

For years ending December 31,

2018	$	658
2019		410
		1,068
Less: Interest		(27	)
Present value of minimum lease payments		1,041
Less: Current portion		(646	)
Long-term portion	$	395

Accrued Liabilities and Other Long-Term Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Accrued Liabilities Current And Noncurrent [Abstract]

Schedule of Accrued Liabilities

Accrued liabilities and other current liabilities at December 31 were:

	2017		2016
Accrued expenses	$	29,764	$	33,947
Compensation and payroll taxes		34,359		23,720
Equipment purchases		20,637		6,377
Accrued pricing adjustments		11,410		3,817
Accrued professional services		2,088		2,645
Other		1,043		1,056
	$	99,301	$	71,562

Schedule of Other Long-Term Liabilities

Other long-term liabilities at December 31 were:

	2017		2016
Accrued defined benefit plan	$	34,428	$	30,515
Unrecognized tax benefits		24,211		15,340
Deferred grant and subsidy		17,173		18,259
Income tax contingencies		8,319		8,163
Deferred compensation		8,870		6,433
Other		1,924		2,663
	$	94,925	$	81,373

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Significant Components of Provisional Amount of Tax Expense

Component	Provisional Amount
Remeasurement of U.S. deferred tax assets and liabilities	$	2,913
Transition tax on foreign earnings		104,327
Foreign tax credits used to offset transition tax		(58,975	)
Other adjustments		(2,357	)
Total net tax expense related to the Tax Act	$	45,908

Schedule of Components of Income Tax Expense (Benefit)

Income (loss) before income taxes	2017			2016			2015
U.S.	$	(72,668	)	$	(40,861	)	$	(21,091	)
Foreign		135,259			65,896			61,686
Total	$	62,591		$	25,035		$	40,595

The components of the income tax provision (benefit) are as follows for the years ended December 31:

	2017			2016			2015
Current tax provision (benefit)
Federal	$	-		$	-		$	12
Foreign		31,820			28,993			17,983
State		7			13			29
		31,827			29,006			18,024
Deferred tax provision (benefit)
Federal		30,186			(10,517	)		(2,739	)
Foreign		(2,352	)		(13,847	)		(1,063	)
State		(8	)		101			(228	)
		27,826			(24,263	)		(4,030	)
Liability for unrecognized tax benefits		2,672			1,815			88
Total income tax provision	$	62,325		$	6,558		$	14,082

Schedule of Effective Income Tax Rate Reconciliation

Reconciliation between the effective tax rate and the statutory tax rates for the years ended December 31, 2017, 2016, and 2015 is as follows:

	2017						2016						2015
				Percent						Percent						Percent
				of pretax						of pretax						of pretax
	Amount			earnings			Amount			earnings			Amount			earnings
Federal tax	$	21,907			35.0		$	8,762			35.0		$	14,214			35.0
State income taxes, net of federal tax provision		(15	)		-			(65	)		(0.3	)		(152	)		(0.4	)
Foreign income taxed at lower tax rates		(23,515	)		(37.6	)		(6,955	)		(27.8	)		(10,126	)		(24.9	)
U.S. tax impact of foreign operations		6,726			10.7			324			1.3			2,046			5.0
Foreign withholding taxes		4,343			6.9			4,834			19.3			2,268			5.6
Research and development		(2,643	)		(4.2	)		(2,241	)		(9.0	)		(2,068	)		(5.1	)
Liability for unrecognized tax benefits		2,672			4.3			1,815			7.3			88			0.2
Valuation allowance		2,077			3.3			(2,600	)		(10.4	)		3,580			8.8
Provision-to-return adjustments		131			0.2			(61	)		(0.2	)		994			2.4
Employee stock-based compensation		1,537			2.5			-			-			-			-
U.S. Tax Cuts and Jobs Act		45,908			73.4			-			-			-			-
Other		3,197			5.1			2,745			11.0			3,238			8.1
Income tax provision	$	62,325			99.6		$	6,558			26.2		$	14,082			34.7

Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible

	2017			2016			2015
Balance at January 1,	$	28,849		$	26,503		$	19,488
Additions based on tax positions related to the current year		3,492			6,746			3,450
Additions for prior year tax positions		863			960			6,963
Reductions for prior year tax positions		(2,623	)		(5,360	)		(3,398	)
Balance at December 31,	$	30,581		$	28,849		$	26,503

Schedule of Deferred Tax Assets and Liabilities

The table below sets forth our deferred tax assets and liabilities as of December 31, 2017 and 2016:

	2017			2016
Deferred tax assets
Inventory cost	$	8,000		$	6,923
Accrued expenses and accounts receivable		690			2,112
Foreign tax credits		10,626			19,610
Research and development tax credits		15,828			13,633
Net operating loss carryforwards		5,392			37,379
Accrued pension		5,428			5,494
Share based compensation and others		12,443			16,992
		58,407			102,143
Valuation allowances		(22,560	)		(32,082	)
Total deferred tax assets, non-current		35,847			70,061
Deferred tax liabilities
Plant, equipment and intangible assets		(17,278	)		(28,639	)
Total deferred tax liabilities, non-current		(17,278	)		(28,639	)
Net deferred tax assets	$	18,569		$	41,422

Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Compensation And Retirement Disclosure [Abstract]

Schedule of Net Benefit Costs

The table below sets forth net periodic benefit costs of the plan for the years ended December 31, 2017 and 2016:

	Defined Benefit Plan

	2017			2016
Components of net periodic benefit cost:
Service cost	$	258		$	270
Interest cost		4,228			5,151
Recognized actuarial loss		1,325			993
Expected return on plan assets		(6,506	)		(6,210	)
Net periodic benefit cost	$	(695	)	$	204

Schedule of Benefit Obligation, Fair Value of Plan Assets, and Funded Status of our Plan

The table below sets forth the benefit obligation, the fair value of plan assets, and the funded status as of December 31:

	Defined Benefit Plan

	2017			2016
Change in benefit obligation:
Beginning balance	$	146,801		$	145,019
Service cost		258			270
Interest cost		4,228			5,151
Actuarial loss		4,910			29,793
Benefits paid		(4,313	)		(6,816	)
Currency changes		14,179			(26,616	)
Benefit obligation at December 31	$	166,063		$	146,801

Change in plan assets:
Beginning balance - fair value	$	118,658		$	116,386
Employer contribution		2,974			2,105
Actual return on plan assets		5,454			28,422
Benefits paid		(4,313	)		(6,816	)
Currency changes		11,461			(21,439	)
Fair value of plan assets at December 31	$	134,234		$	118,658
Underfunded status at December 31	$	(31,829	)	$	(28,143	)

Schedule of Assumptions Used

The following weighted-average assumptions were used to determine net periodic benefit costs for the twelve months ended December 31:

	2017		2016
Discount rate		2.8%	2.8%
Expected long-term return on plan assets		5.4%	5.4%

The following weighted-average assumption was used to determine the benefit obligations at December 31:

	2017			2016
Discount rate	2.6%			2.8%

Schedule of Allocation Of Plan Assets

The table below sets forth the plan asset allocations of the assets in the plan and expected long-term return by asset category

Asset category	Expected long-term return			Asset allocation
Growth assets		7.7	%		64	%
Hedging assets		1.8	%		34	%
Cash		0.5	%		2	%
Total		5.5	%		100	%

Schedule of Expected Benefit Payments

2018	$	3,845
2019		3,998
2020		4,376
2021		4,871
2022		5,267
2023-2026		24,455

Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets

The following table summarizes the major categories of the plan assets

December 31, 2017
Asset category	Level 1		Level 2		Level 3		Total
Cash and cash equivalents	$	2,182	$	4,915	$	-	$	7,097
Equity securities:
U.K.		-		2,787		-		2,787
North America		-		16,082		-		16,082
Europe (excluding U.K.)		-		5,713		-		5,713
Japan		-		2,703		-		2,703
Pacific Basin (excluding Japan)		-		1,372		-		1,372
Emerging markets		-		4,448		-		4,448
Fixed income securities:
Corporate bonds		-		3,682		-		3,682
Others		-		5,731		-		5,731
Index linked securities:
Others		-		203		-		203
Other types of investments:
Absolute return funds		-		1,291		-		1,291
Hedge funds		-		27,355		-		27,355
Development REITS		-		6,004		-		6,004
Insurance linked securities		-		4,117		-		4,117
Liability driven investments		-		45,450		-		45,450
Other		-		199		-		199
Total	$	2,182	$	132,052	$	-	$	134,234

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Share Based Compensation [Abstract]

Schedule of Share-Based Compensation Expense

The table below sets forth the line items where share-based compensation expense was recorded for the twelve months ended December 31, 2017, 2016 and 2015:

	2017		2016		2015
Cost of goods sold	$	645	$	775	$	716
Selling, general and administrative expense		15,130		10,567		16,228
Research and development expense		2,834		2,687		2,026
Total share-based compensation expense	$	18,609	$	14,029	$	18,970

Schedule of Share-Based Compensation Expense by Type

The table below sets forth share-based compensation expense by type for the twelve months ended December 31, 2017, 2016 and 2015:

	2017		2016		2015
Stock options	$	934	$	1,511	$	2,516
Share grants		17,675		12,518		16,454
Total share-based compensation expense	$	18,609	$	14,029	$	18,970

Schedule of Share Based Compensation Stock Options Activity

The table below sets forth a summary of activity in our stock option plans:

Stock Options	Shares			Weighted Average Exercise Price ($)		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value
Outstanding at December 31, 2014		2,736			21.26
Granted		-			-
Exercised		(653	)		15.63
Forfeited or expired		(20	)		22.91
Outstanding at December 31, 2015		2,063			23.03
Granted		-			-
Exercised		(7	)		18.48
Forfeited or expired		(223	)		22.75
Outstanding at December 31, 2016		1,833			23.08
Granted		-			-
Exercised		(581	)		23.42
Forfeited or expired		(24	)		26.87
Outstanding at December 31, 2017		1,228			22.85		3.1	$	7,298
Exercisable at December 31, 2017		1,186			22.67		3.1	$	7,266

Schedule of Stock Options Outstanding

The table below sets forth information about stock options outstanding at December 31, 2017:

Plan	Range of exercise prices		Number outstanding		Weighted average remaining contractual life (years)		Weighted average exercise price
2001 Plan	$	15.05-29.21		917		2.9	$	21.90
2013 Plan	$	23.35-27.92		311		3.9	$	25.29

Schedule of Nonvested Restricted Stock Units Activity

The table below sets forth a summary of our non-vested share grants in 2017, 2016 and 2015:

Restricted Stock Grants	Shares			Weighted Average Grant Date Fair Value ($)		Aggregate Intrinsic Value
Nonvested at December 31, 2014		1,535			23.32
Granted		1,557			22.46
Vested		(370	)		25.02
Forfeited		(43	)		26.08
Nonvested at December 31, 2015		2,679			23.51
Granted		880			18.63
Vested		(877	)		18.92
Forfeited		(62	)		20.80
Nonvested at December 31, 2016		2,620			21.31
Granted		746			25.23
Vested		(645	)		21.89
Forfeited		(441	)		22.31
Nonvested at December 31, 2017		2,280			22.24	$	65,357

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2017

Schedule Net Sales and Purchases of Related Party Transactions

The table below sets forth net sales and purchases from related parties for the twelve months ended December 31:

	2017		2016		2015
LSC
Net sales	$	1,406	$	852	$	588
Purchases	$	24,313	$	21,936	$	22,378
Keylink
Net sales	$	8,856	$	9,125	$	9,749
Purchases	$	3,827	$	5,054	$	6,272
Nuvoton
Purchases	$	11,407	$	10,386	$	12,598
JCP
Purchases	$	1,105	$	826	N/A

Schedule of Account Receivable and Payable of Related Party Transactions

The table below sets forth accounts receivable from and accounts payable to related parties at December 31:

	2017		2016
LSC
Accounts receivable	$	342	$	301
Accounts payable	$	3,308	$	4,333
Keylink
Accounts receivable	$	4,089	$	5,394
Accounts payable	$	5,016	$	4,295
Nuvoton
Accounts payable	$	1,121	$	950
JCP
Accounts payable	$	317	$	263

Segment Information and Enterprise-Wide Disclosures (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of Net Sales from External Customers and Long Lived Assets by Geographical Areas

2017	Asia			North America			Europe			Consolidated
Total sales	$	968,720		$	171,964		$	175,004		$	1,315,688
Inter-company sales		(128,924	)		(71,608	)		(60,952	)		(261,484	)
Net sales	$	839,796		$	100,356		$	114,052		$	1,054,204

Property, plant and equipment	$	390,850		$	44,523		$	23,796		$	459,169
Assets	$	1,061,686		$	230,997		$	195,990		$	1,488,673

2016	Asia			North America			Europe			Consolidated
Total sales	$	895,608		$	109,442		$	157,343		$	1,162,393
Inter-company sales		(137,959	)		(22,034	)		(60,238	)		(220,231	)
Net sales	$	757,649		$	87,408		$	97,105		$	942,162

Property, plant and equipment	$	329,587		$	57,145		$	15,256		$	401,988
Assets	$	948,923		$	400,472		$	179,157		$	1,528,552

2015	Asia			North America			Europe			Consolidated
Total sales	$	793,960		$	143,800		$	164,304		$	1,102,064
Inter-company sales		(118,415	)		(60,882	)		(73,863	)		(253,160	)
Net sales	$	675,545		$	82,918		$	90,441		$	848,904

Property, plant and equipment	$	362,186		$	58,152		$	19,002		$	439,340
Assets	$	969,352		$	463,967		$	165,508		$	1,598,827

Schedule of Net Sales by Countries

			% of Total
2017	Net Sales		Net Sales
China	$	593,098		56	%
U.S.		86,276		8	%
Korea		65,849		6	%
Germany		74,303		7	%
Singapore		58,570		6	%
Taiwan		67,399		6	%
All others		108,709		11	%
Total	$	1,054,204		100	%

			% of Total
2016	Net Sales		Net Sales
China	$	548,015		58	%
U.S.		79,869		8	%
Korea		60,672		6	%
Germany		61,415		7	%
Singapore		48,464		5	%
Taiwan		59,087		6	%
All others		84,640		10	%
Total	$	942,162		100	%

			% of Total
2015	Net Sales		Net Sales
China	$	507,783		60	%
U.S.		76,870		9	%
Korea		66,605		8	%
Germany		57,036		7	%
Singapore		51,742		6	%
Taiwan		30,127		4	%
All others		58,741		6	%
Total	$	848,904		100	%

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rental Payments for Operating Leases

2018	$	9,187
2019		7,662
2020		5,642
2021		3,931
2022		3,365
Thereafter		2,068
	$	31,855

Summary of Land Right Leases

In addition, we have the following land right leases. None of the leases requires a rental payment.

Location	Term (years)	Expiration Date
Chengdu, China	50	2061
Shanghai, China	50	2056
Shandong, China	50	2058
Shanghai, China	50	2058
Yangzhou, China	50	2065

Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Summary of Outstanding Foreign Currency Forward Contracts

The table below sets forth outstanding foreign currency forward contracts at December 31, 2017:

Notional Amount		Effective Date	Maturity Date	Index*	Weighted Average Strike Rate	Cash Flow Hedge Designation
$	2,494	December 2017	December 2017	EUR/GPB	1.2009	Non-designated
	10,514	December 2017	December 2017	EUR/USD	1.2009	Non-designated
	10,612	December 2017	December 2017	GPB/USD	1.3541	Non-designated
	31,834	December 2017	December 2017	USD/CNY	6.5343	Non-designated
	1,594	December 2017	December 2017	USD/JPY	112.35	Non-designated
	30,594	December 2017	December 2017	USD/TWD	29.406	Non-designated

* EUR = Euro
GBP = British Pound Sterling
USD = United States Dollar
CNY = Chinese Yuan Renminbi
JPY = Japan Yen
TWD = Taiwan dollar

Summary of Information Related to Number of and Notional Amount of Interest Rate Related Derivative Instruments

The table below sets forth information related to the number of and the notional amount of our interest rate related derivative instruments at December 31 2017 and December 31, 2016:

	Number of Instruments		Notional Amount
	2017	2016	2017		2016
Interest rate swaps and collars	14	6	$	220,000	$	150,000

Summary of Fair Value of Interest Rate Related Derivative Financial Instruments and Their Classification on the Consolidated Balance Sheets

	Fair Value
	Other Current Assets				Other Assets				Other Liabilities
	2017		2016		2017		2016		2017		2016
Interest rate swaps and collars	$	486	$	-	$	3,398	$	3,052	$	-	$	735

Summary of Effect of Derivative Financial Instruments on the Consolidated Statements of Income

The tables below sets forth the effect of the Company’s derivative financial instruments on the Consolidated Statements of Income for the years ended December 31, 2017 and 2016:

Derivatives Designated as Hedging Instruments	Amount of Gain or (Loss) Recognized in OCI on Derivative				Location of Gain or (Loss) Reclassified from Accumulated OCI into Income	Amount of Gain or (Loss) Reclassified from Accumulated OCI into Net Income
	2017		2016			2017		2016
Interest rate swaps and collars	$	1,567	$	2,317	Interest expense	$	577	$	112

Derivatives Not Designated as Hedging Instruments	Amount of Gain or (Loss) Recognized in Net Income				Location of Gain or (Loss) Reclassified from Accumulated OCI into Income
	2017		2016
Foreign currency forward contracts	$	1,491	$	-	Foreign currency (loss) gain, net

Restructuring Costs (Tables)

12 Months Ended

Dec. 31, 2017

Restructuring And Related Activities [Abstract]

Schedule of Restructuring Costs, Recorded in Restructuring Expense in Condensed Consolidated Statements of Operations, Incurred


Early termination of supply contract	$	1,985
Asset retirement obligation		1,403
Retention cost		3,158
Cost of equipment relocation, shutdown cost and other		3,591
Total	$	10,137

Schedule of Costs Accrued Related to Restructuring

The table below sets forth the costs accrued related to the KFAB restructuring:

	Early Contract Termination			Retention Costs			Equipment Relocation, Shutdown Cost and Other			Total
Beginning balance, January 1, 2017	$	-		$	-		$	-		$	-
Costs accrued		1,985			3,158			3,591			8,734
Restructuring costs paid		(1,985	)		(2,499	)		(2,946	)		(7,430	)
Balance at December 31, 2017	$	-		$	659		$	645		$	1,304

Schedule of Asset Retirement Obligation Related to Restructuring

The table below sets forth the asset retirement obligation related to the KFAB restructuring:

Asset retirement obligation, January 1, 2017	$	486
Accrual of additional asset retirement obligation		1,403
Amount paid		(1,500	)
Asset retirement obligation, December 31, 2017	$	389

Business Combination (Tables)

12 Months Ended

Dec. 31, 2017

Business Combinations [Abstract]

Schedule of Business Acquisitions, by Acquisition

The table below sets forth the estimated purchase price and related costs for Pericom:

Cash consideration for shares outstanding	$	391,123
Cash consideration for vested stock awards, including taxes of $88		7,371
Value of Diodes stock to be issued in exchange for unvested Pericom employee stock awards.		4,680
Total purchase price	$	403,174

Business Acquisition, Pro Forma Information

The table below sets for the unaudited pro forma consolidated results of operations for the twelve month ended December 31, 2015 as if the acquisition of Pericom had occurred at January 1, 2014:

	Twelve Months Ended
	December 31, 2015
Net revenues	$	960,019
Net income attributable to common stockholders	$	40,180
Earnings per share—Basic	$	0.82
Earnings per share—Diluted	$	0.80

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Selected Quarterly Financial Information [Abstract]

Schedule of Quarterly Financial Data


	1st Quarter			2nd Quarter		3rd Quarter		4th Quarter
2017
Net sales	$	236,303		$	264,224	$	285,247	$	268,430
Gross profit		73,911			90,139		96,347		96,379
Net income (loss) attributable to common shareholders		1,217			13,179		14,450		(30,651	)
Earnings (loss) per share attributable to common shareholders
Basic	$	0.03		$	0.27	$	0.29	$	(0.62	)
Diluted	$	0.02		$	0.26	$	0.29	$	(0.62	)


	1st Quarter			2nd Quarter		3rd Quarter		4th Quarter
2016
Net sales	$	222,738		$	236,645	$	250,694	$	232,085
Gross profit		64,220			74,817		80,623		67,263
(Loss) net income attributable to common shareholders		(1,733	)		5,752		10,648		1,268
(Loss) earnings per share attributable to common shareholders
Basic	$	(0.04	)	$	0.12	$	0.22	$	0.07
Diluted	$	(0.04	)	$	0.12	$	0.21	$	0.07

Summary of Operations and Significant Accounting Policies - Additional Information (Details) shares in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2018	Dec. 31, 2017 USD ($) Segment shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Summary Of Operations And Significant Accounting Policies [Line Items]
Product returns and other allowances			$ 158,100,000	$ 132,900,000	$ 113,500,000
Allowance for doubtful accounts	$ 4,500,000		$ 4,500,000	2,100,000
Number of operating segment \| Segment			1
Impairment of goodwill			$ 0	$ 0	$ 0
U.S. federal corporate tax rate			35.00%	35.00%	35.00%
Net tax expense related to the Tax Act	45,908,000
Shipping, Handling and Transportation Costs			$ 15,200,000	$ 14,200,000	$ 8,300,000
Options and share grants outstanding \| shares			3.5	1.4	1.4
Foreign exchange transaction (losses) gains			$ (7,995,000)	$ 2,171,000	$ 1,257,000
Accumulated other comprehensive loss	$ 83,480,000		83,480,000	112,666,000	84,400,000
Increase in deferred income tax assets due to effect on adoption			(25,326,000)	15,978,000	(1,484,000)
Increase in additional paid in capital due to effect on adoption				$ (567,000)	$ (4,029,000)
ASU No. 2016-09 \| Adoption Related to Income Tax Portion [Member]
Summary Of Operations And Significant Accounting Policies [Line Items]
Increase (decrease) in retained earnings due to effect on adoption			4,800,000
Increase in deferred income tax assets due to effect on adoption			4,800,000
ASU No. 2016-09 \| Adoption Related to Forfeitures [Member]
Summary Of Operations And Significant Accounting Policies [Line Items]
Increase (decrease) in retained earnings due to effect on adoption			(500,000)
Increase in deferred income tax assets due to effect on adoption			300,000
Increase in additional paid in capital due to effect on adoption			$ 800,000
Restricted Stock
Summary Of Operations And Significant Accounting Policies [Line Items]
Requisite service period			4 years
Scenario, Forecast
Summary Of Operations And Significant Accounting Policies [Line Items]
U.S. federal corporate tax rate		21.00%
Minimum \| Building
Summary Of Operations And Significant Accounting Policies [Line Items]
Estimated useful lives			20 years
Minimum \| Machinery and Equipment
Summary Of Operations And Significant Accounting Policies [Line Items]
Estimated useful lives			3 years
Minimum \| Leaseholds and Leasehold Improvements
Summary Of Operations And Significant Accounting Policies [Line Items]
Estimated useful lives			3 years
Maximum \| Building
Summary Of Operations And Significant Accounting Policies [Line Items]
Estimated useful lives			55 years
Maximum \| Machinery and Equipment
Summary Of Operations And Significant Accounting Policies [Line Items]
Estimated useful lives			10 years
Maximum \| Leaseholds and Leasehold Improvements
Summary Of Operations And Significant Accounting Policies [Line Items]
Estimated useful lives			5 years

Summary of Operations and Significant Accounting Policies - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings (numerator)
Net (loss) income attributable to common stockholders	$ (30,651)	$ 14,450	$ 13,179	$ 1,217	$ 1,268	$ 10,648	$ 5,752	$ (1,733)	$ (1,805)	$ 15,935	$ 24,274
Shares (denominator)
Weighted average common shares outstanding (basic)									48,824	48,597	48,210
Dilutive effect of stock options and stock awards outstanding										1,192	1,290
Adjusted weighted average common shares outstanding (diluted)									48,824	49,789	49,500
(Loss) earnings per share attributable to common stockholders
Basic	$ (0.62)	$ 0.29	$ 0.27	$ 0.03	$ 0.07	$ 0.22	$ 0.12	$ (0.04)	$ (0.04)	$ 0.33	$ 0.50
Diluted	$ (0.62)	$ 0.29	$ 0.26	$ 0.02	$ 0.07	$ 0.21	$ 0.12	$ (0.04)	$ (0.04)	$ 0.32	$ 0.49

Summary of Operations and Significant Accounting Policies - Component of Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Unrealized foreign currency losses	$ (42,010)	$ (75,075)
Unrealized gain on interest rate swap, net of tax	2,524	1,506
Unrealized loss on defined benefit plan	$ (43,994)	$ (39,097)

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Short-term investments	$ 4,558	$ 29,842

Fair Value Measurements - Schedule of Financial Assets At Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 4,558	$ 29,842
Interest Rate Swaps and Collars
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of derivative instruments, asset derivatives	3,884
Interest Rate Swap Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of derivative instruments, asset derivatives		2,317
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	2,586	2,737
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	1,972	27,105
Significant Other Observable Inputs (Level 2) \| Interest Rate Swaps and Collars
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of derivative instruments, asset derivatives	$ 3,884
Significant Other Observable Inputs (Level 2) \| Interest Rate Swap Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of derivative instruments, asset derivatives		$ 2,317

Inventories - Schedule of Inventory Current (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Finished goods	$ 81,194	$ 66,930
Work-in-progress	52,578	45,408
Raw materials	82,734	81,145
Total	$ 216,506	$ 193,483

Property, Plant and Equipment - Schedule of Property Plant And Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Buildings and leasehold improvements, Gross	$ 203,054	$ 192,290
Machinery and equipment	774,138	685,249
Property, plant and equipment, at cost	977,192	877,539
Less: Accumulated depreciation and amortization	(581,753)	(535,407)
Net	395,439	342,132
Construction in-progress	22,446	24,049
Land	41,284	35,807
Property, plant and equipment, net	$ 459,169	$ 401,988	$ 439,340

Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Depreciation	$ 76,883	$ 78,482	$ 71,504
Capital lease obligations	$ 1,000	$ 1,100

Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	$ 234,533	$ 232,747
Accumulated Amortization	(88,059)	(69,247)
Currency Exchange	(8,249)	(8,442)
Amortization of Intangible Assets, Net	138,225	155,058
Gross Carrying Amount	19,217	21,003
Currency Exchange	(997)	(1,185)
Net	18,220	19,818
Total Intangible Assets - Gross Carrying Amount	253,750	253,750
Total Intangible Assets - Accumulated Amortization	(88,059)	(69,247)
Total Intangible Assets - Currency Exchange and Other	(9,246)	(9,627)
Total Intangible Assets - Net	156,445	174,876
In Process Research and Development
Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	8,914	10,700
Net	8,914	10,700
Trademarks and Trade Names
Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	10,303	10,303
Currency Exchange	(997)	(1,185)
Net	9,306	9,118
Patents
Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	11,823	11,823
Accumulated Amortization	(9,154)	(8,431)
Currency Exchange	(242)	(255)
Amortization of Intangible Assets, Net	$ 2,427	$ 3,137
Patents \| Minimum
Intangible Assets Net Excluding Goodwill [Line Items]
Useful life	5 years	5 years
Patents \| Maximum
Intangible Assets Net Excluding Goodwill [Line Items]
Useful life	15 years	15 years
Software License
Intangible Assets Net Excluding Goodwill [Line Items]
Useful life	3 years	3 years
Gross Carrying Amount	$ 1,212	$ 1,212
Accumulated Amortization	(1,149)	(1,149)
Currency Exchange	(63)	(63)
Developed Product Technology
Intangible Assets Net Excluding Goodwill [Line Items]
Gross Carrying Amount	154,795	153,009
Accumulated Amortization	(53,925)	(41,416)
Currency Exchange	(6,219)	(6,299)
Amortization of Intangible Assets, Net	$ 94,651	$ 105,294
Developed Product Technology \| Minimum
Intangible Assets Net Excluding Goodwill [Line Items]
Useful life	2 years	2 years
Developed Product Technology \| Maximum
Intangible Assets Net Excluding Goodwill [Line Items]
Useful life	10 years	10 years
Customer Relationships
Intangible Assets Net Excluding Goodwill [Line Items]
Useful life	12 years	12 years
Gross Carrying Amount	$ 62,093	$ 62,093
Accumulated Amortization	(19,319)	(13,915)
Currency Exchange	(1,650)	(1,750)
Amortization of Intangible Assets, Net	$ 41,124	$ 46,428
Other
Intangible Assets Net Excluding Goodwill [Line Items]
Useful life	4 years	4 years
Gross Carrying Amount	$ 4,610	$ 4,610
Accumulated Amortization	(4,512)	(4,336)
Currency Exchange	(75)	(75)
Amortization of Intangible Assets, Net	$ 23	$ 199

Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets Net Excluding Goodwill [Abstract]
Amortization of intangibles	$ 18,798	$ 20,483	$ 8,596

Intangible Assets - Schedule of Expected Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2018	$ 18,003
2019	17,498
2020	15,472
2021	14,775
2022	13,956
2023 and thereafter	58,521
Amortization of Intangible Assets, Net	$ 138,225	$ 155,058

Goodwill - Schedule of Changes in Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill
Goodwill beginning balance	$ 129,412	$ 132,913
Pericom measurement period adjustment		2,741
Foreign currency translation adjustment	4,775	(6,242)
Goodwill ending balance	$ 134,187	$ 129,412

Bank Credit Agreements and Other Short-Term and Long-Term Debt - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Line Of Credit Facility [Line Items]
Long-term debt	$ 270,083,000	$ 429,841,000
Term Loan
Line Of Credit Facility [Line Items]
Long-term debt	165,800,000
U.S. Credit Facility
Line Of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	250,000,000
Long-term debt	$ 268,800,000
Line of credit facility, maturity date	Oct. 26, 2021
U.S. Credit Facility \| Maximum
Line Of Credit Facility [Line Items]
Line of credit facility increase in borrowing capacity	$ 200,000,000
U.S. Credit Facility \| Final Year
Line Of Credit Facility [Line Items]
Debt instrument, quarterly periodic payment	9,400,000
U.S. Credit Facility \| Term Loan
Line Of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	250,000,000
U.S. Credit Facility \| Term Loan \| 2016
Line Of Credit Facility [Line Items]
Debt instrument, quarterly periodic payment	3,100,000
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Long-term debt	103,000,000
Short-Term Debt
Line Of Credit Facility [Line Items]
Lines of credit unused and available	78,700,000
Line of credit facility advanced under foreign credit line	1,000,000
Line of Credit Facility Credit Used For Guarantee	900,000
Short-Term Debt \| Unsecured
Line Of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	$ 80,500,000

Bank Credit Agreements and Other Short-Term and Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total long-term debt	$ 270,083	$ 429,841
Current portion of long-term debt	(20,636)	(14,356)
Less: Unamortized debt issuance costs	(1,955)	(2,359)
Long-term debt, net of current portion	247,492	413,126
Notes Payable To Bank
Debt Instrument [Line Items]
Total long-term debt	1,271	1,466
Term Loan and Revolver
Debt Instrument [Line Items]
Total long-term debt	$ 268,812	$ 428,375

Bank Credit Agreements and Other Short-Term and Long-Term Debt - Schedule of Debt (Parenthetical) (Details) - Notes Payable To Bank TWD in Millions	12 Months Ended
	Dec. 31, 2017 TWD
Debt Instrument [Line Items]
Long-term Debt, Gross	TWD 132
Long-term variable interest rate	1.70%
Debt Instrument, maturity date, description	TWD 132 million, variable interest (approximately 1.7% as of December 31, 2017), matures July 6, 2021
Debt instrument, maturity date	Jul. 06, 2021

Bank Credit Agreements and Other Short-Term and Long-Term Debt - Schedule of Maturities of Long Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Long Term Debt By Current And Noncurrent [Abstract]
2018	$ 20,636
2019	26,892
2020	33,147
2021	189,408
Total long-term debt	$ 270,083	$ 429,841

Capital Lease Obligations - Summary of Future Minimum Lease Payments under Capital Lease Agreement (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Capital Lease Obligations [Abstract]
2018	$ 658
2019	410
Capital leases, future minimum payment, total	1,068
Less: Interest	(27)
Present value of minimum lease payments	1,041
Less: Current portion	(646)
Long-term portion	$ 395

Capital Lease Obligations - Additional Information (Details) $ in Millions	Dec. 31, 2017 USD ($)
Capital Lease Obligations [Abstract]
Capital leases costs	$ 3.7
Capital leases, accumulated depreciation	$ 2.6

Accrued Liabilities and Other Current Liabilities, and Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities, Current [Abstract]
Accrued expenses	$ 29,764	$ 33,947
Compensation and payroll taxes	34,359	23,720
Equipment purchases	20,637	6,377
Accrued pricing adjustments	11,410	3,817
Accrued professional services	2,088	2,645
Other	1,043	1,056
Accrued Liabilities, Current, Total	99,301	71,562
Liabilities, Noncurrent [Abstract]
Accrued defined benefit plan	34,428	30,515
Unrecognized tax benefits	24,211	15,340
Deferred grant and subsidy	17,173	18,259
Income tax contingencies	8,319	8,163
Deferred compensation	8,870	6,433
Other	1,924	2,663
Other long-term liabilities, Total	$ 94,925	$ 81,373

Stockholders' Equity - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Nov. 30, 2015
Equity Class Of Treasury Stock [Line Items]
Other Restrictions on Payment of Dividends	Our U.S. Credit Facility permits us to pay dividends up to $3.0 million per fiscal year to its stockholders so long as we have not defaulted at the time of such dividend and no default would result from declaring or paying such dividend.
Common stock par value	$ 0.666	$ 0.666
Stock repurchase program expiration date	Dec. 31, 2019
Common shares repurchased during period, shares	300,000	691,196
Common shares repurchased during period, value	$ 8,745,000	$ 18,014,000	$ 11,009,000
Stock Repurchase Program
Equity Class Of Treasury Stock [Line Items]
Common stock par value				$ 0.666
Stock Repurchase Program \| Maximum
Equity Class Of Treasury Stock [Line Items]
Authorized amount of common stock under stock repurchase program				$ 100,000,000

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Credit Carryforward [Line Items]
U.S. federal corporate tax rate			35.00%	35.00%	35.00%
Net tax expense related to the Tax Act	$ 45,908,000
Additional income taxes on undistributed foreign earnings	0		$ 0
Significant change in unrecognized tax benefits, nature of event			It is reasonably possible that the amount of the unrecognized benefit with respect to certain of our unrecognized tax positions will significantly increase or decrease within the next 12 months.
Significant change in unrecognized tax benefits is reasonably possible, estimated range not possible			These changes may be the result of settlements of ongoing audits or competent authority proceedings. At this time, an estimate of the range of the reasonably possible outcomes cannot be made.
Unrecognized tax benefits	30,581,000		$ 30,581,000	$ 28,849,000	$ 26,503,000	$ 19,488,000
Unrecognized tax benefits, if recognized, would affect the effective tax rate	27,200,000		$ 27,200,000
Income tax examination, description			We file income tax returns in the U.S. federal jurisdiction and in various state and foreign jurisdictions. We are no longer subject to U.S. federal income tax examinations by tax authorities for tax years before 2008, or for the 2010 and 2011 tax years. We are no longer subject to China income tax examinations by tax authorities for tax years before 2007. With respect to state and local jurisdictions and countries outside of the U.S., with limited exceptions, we are no longer subject to income tax audits for years before 2012. Although the outcome of tax audits is always uncertain, we believe that adequate amounts of tax, interest and penalties, if any, have been provided for in our reserve for any adjustments that may result from future tax audits. We recognize accrued interest and penalties, if any, related to unrecognized tax benefits in interest expense. We had an immaterial amount of accrued interest and penalties at December 31, 2017, 2016 and 2015.
Net deferred tax assets	18,569,000		$ 18,569,000	41,422,000
Tax credit carryforward, valuation allowance	13,000,000		13,000,000	22,400,000
Operating loss carryforward [Abstract]
Operating loss carryforwards, valuation allowance	5,000,000		5,000,000	5,900,000
Income taxes supplemental information [Abstract]
Statutory accounting practices, retained earnings not available for dividends	51,000		51,000
Additional tax on undistributed foreign earnings	42,000		42,000
Tax holidays			$ 3,700,000	$ 7,300,000	$ 2,900,000
Tax holidays basic EPS			$ 0.08	$ 0.15	$ 0.06
Tax holidays diluted EPS			$ 0.08	$ 0.15	$ 0.06
China
Income taxes supplemental information [Abstract]
Deferred tax liabilities, undistributed foreign earnings	429,000		$ 429,000
State and Local Jurisdiction
Operating loss carryforward [Abstract]
Operating loss carryforwards	3,000,000		$ 3,000,000
Operating loss carryforwards, expiration dates			Jan. 01, 2018
Foreign Tax Authority
Operating loss carryforward [Abstract]
Operating loss carryforwards	2,000,000		$ 2,000,000
Operating loss carryforwards, expiration dates			Jan. 01, 2020
Income taxes supplemental information [Abstract]
Deferred tax liabilities, undistributed foreign earnings	770,000		$ 770,000
Federal
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	20,000,000		$ 20,000,000
Tax credit carryforward, expiration dates			Jan. 01, 2021
Research
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	7,000,000		$ 7,000,000
Tax credit carryforward, expiration dates			Jan. 01, 2020
ASU No. 2013-11
Tax Credit Carryforward [Line Items]
Deferred tax assets operating loss carryforwards	3,200,000		$ 3,200,000	$ 13,600,000
Deferred tax assets excluding tax benefits for operating loss carryforwards	$ 15,400,000		15,400,000	$ 27,800,000
ASU No. 2016-09
Tax Credit Carryforward [Line Items]
Increase in income tax expense			1,500,000
ASU No. 2016-09 \| Adoption Related to Income Tax Components
Tax Credit Carryforward [Line Items]
Increase (decrease) in retained earnings due to effect on adoption			$ 4,800,000
Scenario, Forecast
Tax Credit Carryforward [Line Items]
U.S. federal corporate tax rate		21.00%

Income Taxes - Significant Components of Provisional Amount of Tax Expense (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2017 USD ($)
Income Tax Disclosure [Abstract]
Remeasurement of U.S. deferred tax assets and liabilities	$ 2,913
Transition tax on foreign earnings	104,327
Foreign tax credits used to offset transition tax	(58,975)
Other adjustments	(2,357)
Total net tax expense related to the Tax Act	$ 45,908

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S.	$ (72,668)	$ (40,861)	$ (21,091)
Foreign	135,259	65,896	61,686
Income before income taxes and noncontrolling interest	62,591	25,035	40,595
Current tax provision (benefit)
Federal			12
Foreign	31,820	28,993	17,983
State	7	13	29
Current tax provision (benefit), Total	31,827	29,006	18,024
Deferred tax provision (benefit)
Federal	30,186	(10,517)	(2,739)
Foreign	(2,352)	(13,847)	(1,063)
State	(8)	101	(228)
Deferred Income Tax Expense (Benefit), Total	27,826	(24,263)	(4,030)
Liability for unrecognized tax benefits	2,672	1,815	88
Total income tax provision	$ 62,325	$ 6,558	$ 14,082

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Federal tax	$ 21,907	$ 8,762	$ 14,214
State income taxes, net of federal tax provision	(15)	(65)	(152)
Foreign income taxed at lower tax rates	(23,515)	(6,955)	(10,126)
U.S. tax impact of foreign operations	6,726	324	2,046
Foreign withholding taxes	4,343	4,834	2,268
Research and development	(2,643)	(2,241)	(2,068)
Liability for unrecognized tax benefits	2,672	1,815	88
Valuation allowance	2,077	(2,600)	3,580
Provision-to-return adjustments	131	(61)	994
Employee stock-based compensation	1,537
U.S. Tax Cuts and Jobs Act	45,908
Other	3,197	2,745	3,238
Total income tax provision	$ 62,325	$ 6,558	$ 14,082
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Income tax rate, Federal tax	35.00%	35.00%	35.00%
Income tax rate, State income taxes, net of federal tax provision		(0.30%)	(0.40%)
Income tax rate, Foreign income taxed at lower tax rates	(37.60%)	(27.80%)	(24.90%)
Income tax rate, U.S. tax impact of foreign operations	10.70%	1.30%	5.00%
Income tax rate, Foreign withholding taxes	6.90%	19.30%	5.60%
Income tax rate, Research and development	(4.20%)	(9.00%)	(5.10%)
Income tax rate, Liability for unrecognized tax benefits	4.30%	7.30%	0.20%
Income tax rate, Valuation allowance	3.30%	(10.40%)	8.80%
Income tax rate, Provision-to-return adjustment	0.20%	(0.20%)	2.40%
Income tax rate, Employee stock-based compensation	2.50%
Income tax rate, U.S. Tax Cuts and Jobs Act	73.40%
Income tax rate, Other	5.10%	11.00%	8.10%
Income tax rate, Total	99.60%	26.20%	34.70%

Income Taxes - Summary of Positions for which Significant Change in Unrecognized Tax Benefits is Reasonably Possible (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Beginning Balance	$ 28,849	$ 26,503	$ 19,488
Additions based on tax positions related to the current year	3,492	6,746	3,450
Additions for prior year tax positions	863	960	6,963
Reductions for prior year tax positions	(2,623)	(5,360)	(3,398)
Ending Balance	$ 30,581	$ 28,849	$ 26,503

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets
Inventory cost	$ 8,000	$ 6,923
Accrued expenses and accounts receivable	690	2,112
Foreign tax credits	10,626	19,610
Research and development tax credits	15,828	13,633
Net operating loss carryforwards	5,392	37,379
Accrued pension	5,428	5,494
Share based compensation and others	12,443	16,992
Total deferred tax assets, include valuation allowance	58,407	102,143
Valuation allowances	(22,560)	(32,082)
Total deferred tax assets, non-current	35,847	70,061
Deferred tax liabilities
Plant, equipment and intangible assets	(17,278)	(28,639)
Total deferred tax liabilities, non-current	(17,278)	(28,639)
Net deferred tax assets	$ 18,569	$ 41,422

Employee Benefit Plans - Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) $ / £	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 GBP (£) $ / £
Defined Benefit Plan Disclosure [Line Items]
Underfunded pension and postretirement obligation, noncurrent	$ 31,800,000
Accumulated comprehensive loss defined benefit plan	43,994,000	$ 39,097,000
Defined benefit plan recognized gain loss increase(decrease)	4,800,000
Other comprehensive income (loss), pension and other postretirement benefit plans, net unamortized gain (loss) arising during period, before tax	$ 1,100,000
Defined benefit plan amortization of net gains losses average term	13 years
Defined benefit plan, expected future benefit payments in year one	$ 3,845,000
Defined benefit plan, expected future benefit payments in year two	3,998,000
Defined benefit plan, expected future benefit payments in year three	4,376,000
Defined benefit plan, expected future benefit payments in year four	4,871,000
Defined benefit plan, expected future benefit payments in year five	5,267,000
Defined contribution plan, cost recognized	$ 14,800,000	$ 13,900,000	$ 14,000,000
Deferred Compensation Plan
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation arrangements, overall, description	We maintain a Non-Qualified Deferred Compensation Plan (the “Deferred Compensation Plan”) for executive officers, key employees and members of the Board of Directors (the “Board”). The Deferred Compensation Plan allows eligible participants to defer the receipt of eligible compensation, including equity awards, until designated future dates. We offset our obligations under the Deferred Compensation Plan by investing in the actual underlying investments. These investments are classified as trading securities and are carried at fair value. At December 31, 2017, these investments totaled approximately $8.8 million. All gains and losses in these investments are materially offset by corresponding gains and losses in the deferred compensation plan liabilities.
Deferred compensation plan assets	$ 8,800,000
United States
Defined Benefit Plan Disclosure [Line Items]
Employee salary deferral contributions percentage	100.00%
Employer matching contribution amount of match	$ 1
Defined contribution plan employee matching contribution amount	$ 2
Defined contribution plan vesting period	4 years
Description of defined contribution pension and other postretirement plans	We maintain a 401(k) retirement plan (“the Plan”) for the benefit of qualified employees at our U.S. locations. Employees who participate may elect to make salary deferral contributions to the Plan up to 100% of the employees’ eligible payroll subject to annual Internal Revenue Code maximum limitations. We currently make a matching contribution of $1 for every $2 contributed by the participant up to 6% (3% maximum matching) of the participant’s eligible payroll, which vests over an initial four years. In addition, we may make a discretionary contribution to the entire qualified employee pool, in accordance with the Plan.
Taiwan, Province of China
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution percentage	6.00%
Description of defined contribution pension and other postretirement plans	Pursuant to the Taiwan Labor Standard Law and Factory Law, we maintain a retirement plan for the employees in Taiwan, whereby we make contributions at a rate of 6% of the employee’s eligible payroll.
China
Defined Benefit Plan Disclosure [Line Items]
Description of defined contribution pension and other postretirement plans	As stipulated by the regulations of China, we maintain a retirement plan pursuant to the local municipal government for the employees in China. We are required to make contributions to the retirement plan at a rate between 10% and 22% of the employee’s eligible payroll.
Maximum \| United States
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution percentage	6.00%
Employer matching contribution percent of match	3.00%
Maximum \| China
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution percentage	22.00%
Minimum \| China
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution percentage	10.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, target allocation percentage of assets, equity securities	48.00%			48.00%
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, target allocation percentage of assets, equity securities	40.00%			40.00%
Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, target allocation percentage of assets, equity securities	12.00%			12.00%
Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans, general information	In connection with the Zetex acquisition, we adopted a contributory defined benefit plan that covers certain employees in the U.K. The defined benefit plan is closed to new entrants and frozen with respect to future benefit accruals. The retirement benefit is based on the final average compensation and service of each eligible employee. We determined the fair value of the defined benefit plan assets and utilize an annual measurement date of December 31. At subsequent measurement dates, defined benefit plan assets will be determined based on fair value. Defined benefit plan assets consist of a diverse range of listed and unlisted securities including corporate bonds and mutual funds and are denominated in the currency in which the benefits will be paid and that have terms to maturity approximating the terms of the related pension liability. The net pension and supplemental retirement benefit obligations and the related periodic costs are based on, among other things, assumptions of the discount rate, estimated return on plan assets and mortality rates. These obligations and related periodic costs are measured using actuarial techniques and assumptions.
Defined benefit plan, pension, method to determine vested benefit obligation	The projected unit credit method is the actuarial cost method used to compute the pension liabilities and related expenses.
Pension Plan, Defined Benefit \| Trust for Benefit of Employee
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, estimated future employer contributions in current fiscal year, description	We adopted a payment plan with the trustees of the defined benefit plan, in which we would make annual contributions each year through 2030, of approximately GBP 2 million (approximately $2.8 million based on a GBP:USD exchange rate of 1.4). The annual contributions were expected to meet the deficit disclosed in the plan as of April 5, 2013 by December 31, 2030. The trustees are required to review the funding position every three years, and a further review was carried out as of April 5, 2016. The outcome of the review, as agreed with the trustees during the first quarter of 2017, was that contributions would continue at the existing level until December 31, 2029.
Defined benefit plan, expected future benefit payments in year one	$ 2,800,000			£ 2
Defined benefit plan, expected future benefit payments in year two	2,800,000			2
Defined benefit plan, expected future benefit payments in year three	2,800,000			2
Defined benefit plan, expected future benefit payments in year four	2,800,000			2
Defined benefit plan, expected future benefit payments in year five	2,800,000			2
Defined benefit plan, expected future benefit payments in ten fiscal years thereafter	$ 2,800,000			£ 2
GBP:USD exchange rate \| $ / £	1.4			1.4

Employee Benefit Plans - Net periodic benefit costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 258	$ 270
Interest cost	4,228	5,151
Recognized actuarial loss	1,325	993
Expected return on plan assets	(6,506)	(6,210)
Net periodic benefit cost	$ (695)	$ 204

Employee Benefit Plans - Schedule of Benefit Obligation, Fair Value of Plan Assets, and Funded Status of our Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Change in Benefit Obligation [Roll Forward]
Service cost	$ 258	$ 270
Interest cost	4,228	5,151
Change in Plan Assets [Roll Forward]
Fair value of plan assets - ending	134,234
Pension Plan, Defined Benefit
Change in Benefit Obligation [Roll Forward]
Benefit obligation - beginning	146,801	145,019
Service cost	258	270
Interest cost	4,228	5,151
Actuarial loss	4,910	29,793
Benefits paid	(4,313)	(6,816)
Currency changes	14,179	(26,616)
Benefit obligation - ending	166,063	146,801
Change in Plan Assets [Roll Forward]
Fair value of plan assets - beginning	118,658	116,386
Employer contribution	2,974	2,105
Actual return on plan assets	5,454	28,422
Benefits paid	(4,313)	(6,816)
Currency changes	11,461	(21,439)
Fair value of plan assets - ending	134,234	118,658
Underfunded status	$ (31,829)	$ (28,143)

Employee Benefit Plans - Schedule of Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined benefit plan, Weighted average assumptions used in calculating net periodic benefit cost [Abstract]
Expected long-term return on plan assets	5.50%
Pension Plan, Defined Benefit
Defined benefit plan, Weighted average assumptions used in calculating net periodic benefit cost [Abstract]
Discount rate	2.80%	2.80%
Expected long-term return on plan assets	5.40%	5.40%
Defined benefit plan, Weighted average assumptions used in calculating benefit obligation [Abstract]
Discount rate	2.60%	2.80%

Employee Benefit Plans - Expected long-term return by asset category (Details)	12 Months Ended
	Dec. 31, 2017
Expected Long Term Return [Abstract]
Expected long-term return	5.50%
Asset allocation [Abstract]
Asset allocation	100.00%
Growth assets
Expected Long Term Return [Abstract]
Expected long-term return	7.70%
Asset allocation [Abstract]
Asset allocation	64.00%
Hedging assets
Expected Long Term Return [Abstract]
Expected long-term return	1.80%
Asset allocation [Abstract]
Asset allocation	34.00%
Cash
Expected Long Term Return [Abstract]
Expected long-term return	0.50%
Asset allocation [Abstract]
Asset allocation	2.00%

Employee Benefit Plans - Expected future benefit payments (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Defined Benefit Plan Estimated Future Benefit Payments [Abstract]
2018	$ 3,845
2019	3,998
2020	4,376
2021	4,871
2022	5,267
2023-2026	$ 24,455

Share-Based Compensation - Schedule of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 18,609	$ 14,029	$ 18,970
Cost of Goods Sold
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	645	775	716
Selling, General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	15,130	10,567	16,228
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 2,834	$ 2,687	$ 2,026

Share-Based Compensation - Schedule of Share-Based Compensation Expense by Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 18,609	$ 14,029	$ 18,970
Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	934	1,511	2,516
Share Grants
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 17,675	$ 12,518	$ 16,454

Share-Based Compensation - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended								12 Months Ended
	May 31, 2017	May 31, 2013	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, fair value assumptions, method used											Share-based compensation expense for stock options granted in previous years was calculated on the date of grant using the Black-Scholes-Merton option-pricing model
Stock options granted, shares											0	0
Cash proceeds received from stock option exercises											$ 13,600	$ 100	$ 10,200
Performance-based/restricted stock grant covering shares											746,000	880,000	1,557,000
Taxes paid related to net share settlement												$ 2,528
Revenue			$ 268,430	$ 285,247	$ 264,224	$ 236,303	$ 232,085	$ 250,694	$ 236,645	$ 222,738	$ 1,054,204	942,162	$ 848,904
Performance Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock expense												(2,700)
Performance Grants \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based/restricted stock grant covering shares											600,000
Payout percentage of award subject to performance criteria											200.00%
Performance-based grant covering shares											125,810
Incremental expense											$ 3,300
Revenue target for performance-based stock units vesting											$ 1,000,000
Performance Grants \| Chief Executive Officer \| Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based grant covering shares, description											During 2017 the Company modified a performance-based award previously granted to our Chief Executive Officer
Performance Grants \| Chief Executive Officer \| Common Stock \| Previous Performance Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based/restricted stock grant covering shares											700,000
Performance Grants \| Chief Executive Officer \| Common Stock \| Current Performance Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based/restricted stock grant covering shares											62,905
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized			32,400								$ 32,400
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition											2 years 4 months 24 days
Restricted Stock \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental expense											$ 1,700
Restricted Stock \| Chief Executive Officer \| Common Stock \| Current Performance Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based/restricted stock grant covering shares											62,905
Restricted Stock \| Pericom
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock expense													$ 4,000
Performance-based/restricted stock grant covering shares													724,000
Taxes paid related to net share settlement												$ 2,500
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized			$ 300								$ 300
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition											1 year
Stock Options \| Plan 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, description											Stock options under the 2013 Plan generally vest in equal annual installments over a four-year period and expire eight years after the grant date
Share-based compensation arrangement by share-based payment award, award vesting period		4 years
Share-based compensation arrangement by share-based payment award, expiration period		8 years
Share-based compensation arrangement by share-based payment award, number of shares authorized	12,000,000	6,000,000
Share-based compensation arrangement by share-based payment award, number of additional shares authorized	6,000,000
Restricted Stock Awards and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period											4 years

Share-Based Compensation - Schedule of Share Based Compensation Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Options, Shares:
Outstanding Beginning Shares	1,833,000	2,063,000	2,736,000
Granted Shares	0	0
Exercised Shares	(581,000)	(7,000)	(653,000)
Forfeited or Expired Shares	(24,000)	(223,000)	(20,000)
Outstanding Ending Shares	1,228,000	1,833,000	2,063,000
Shares Exercisable	1,186,000
Weighted Average Exercise Price:
Outstanding Beginning Weighted Average Exercise Price	$ 23.08	$ 23.03	$ 21.26
Exercised Weighted Average Exercise Price	23.42	18.48	15.63
Forfeited or Expired Weighted Average Exercise Price	26.87	22.75	22.91
Outstanding Ending Weighted Average Exercise Price	22.85	$ 23.08	$ 23.03
Exercisable Weighted Average Exercise Price	$ 22.67
Weighted Average Remaining Contractual Term:
Outstanding Weighted Average Remaining Contractual Term	3 years 1 month 6 days
Exercisable Weighted Average Remaining Contractual Term	3 years 1 month 6 days
Aggregate Intrinsic Value :
Outstanding Aggregate Intrinsic Value	$ 7,298
Exercisable Aggregate Intrinsic Value	$ 7,266

Share Based Compensation - Schedule of Stock Options Outstanding (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock Options Outstanding [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	1,228	1,833	2,063	2,736
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 1 month 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 22.85	$ 23.08	$ 23.03	$ 21.26
Plan 2001
Stock Options Outstanding [Abstract]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	15.05
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 29.21
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	917
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	2 years 10 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 21.90
Plan 2013
Stock Options Outstanding [Abstract]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	23.35
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 27.92
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	311
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 10 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 25.29

Share-Based Compensation - Schedule of Nonvested Restricted Stock Units Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of the status of non vested share grants [Roll Forward]
Beginning balance nonvested	2,620	2,679	1,535
Granted	746	880	1,557
Vested	(645)	(877)	(370)
Forfeited	(441)	(62)	(43)
Ending balance nonvested	2,280	2,620	2,679
Weighted-Average Grant-Date Fair Value [Roll Forward]
Beginning balance nonvested	$ 21.31	$ 23.51	$ 23.32
Granted	25.23	18.63	22.46
Vested	21.89	18.92	25.02
Forfeited	22.31	20.80	26.08
Ending balance nonvested	$ 22.24	$ 21.31	$ 23.51
Aggregate Intrinsic Value
Balance nonvested	$ 65,357

Related Party Transactions - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Lite On Semiconductor
Related Party Transaction [Line Items]
Related Party ownership of common stock	16.00%
Related Party Transaction, Description of Transaction	LSC is our largest stockholder, owning approximately 16% of our outstanding Common Stock as of December 31, 2017, and is a member of the Lite-On Group of companies.
Lite On Semiconductor \| Maximum
Related Party Transaction [Line Items]
Related Party Transaction Revenues Percentage from Transactions with Related Party	1.00%	1.00%	1.00%
Keylink
Related Party Transaction [Line Items]
Related Party ownership of common stock	5.00%
Related Party Transaction, Description of Transaction	Keylink is our 5% partner in our Shanghai assembly and test facilities.
Related Party Transaction Revenues Percentage from Transactions with Related Party	1.00%	1.00%	1.00%
Related Party Transaction Consulting Fees from Transactions with Related Party	$ 17.1	$ 16.1	$ 17.9
Chengdu Ya Guang Electronic Company Limited ("Ya Guang")
Related Party Transaction [Line Items]
Related Party Transaction, Description of Transaction	In addition, Chengdu Ya Guang Electronic Company Limited (“Ya Guang”) is our 2% partner in one of our Chengdu assembly and test facilities and our 5% partner in our two Chengdu assembly and test facilities
Chengdu Ya Guang Electronic Company Limited ("Ya Guang") \| Chengdu \| Assembly and Test Facility One
Related Party Transaction [Line Items]
Related Party ownership of common stock	2.00%
Chengdu Ya Guang Electronic Company Limited ("Ya Guang") \| Chengdu \| Assembly and Test Facility Two
Related Party Transaction [Line Items]
Related Party ownership of common stock	5.00%

Related Party Transactions - Schedule Net Sales and Purchases of Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Lite On Semiconductor
Related Party Transaction [Line Items]
Net sales from related parties	$ 1,406	$ 852	$ 588
Purchases from related parties	24,313	21,936	22,378
Keylink
Related Party Transaction [Line Items]
Net sales from related parties	8,856	9,125	9,749
Purchases from related parties	3,827	5,054	6,272
Nuvoton
Related Party Transaction [Line Items]
Purchases from related parties	11,407	10,386	$ 12,598
JCP
Related Party Transaction [Line Items]
Purchases from related parties	$ 1,105	$ 826

Related Party Transactions - Schedule of Account Receivable and Payable of Related Party Transactions (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Lite On Semiconductor
Related Party Transaction [Line Items]
Accounts receivable	$ 342	$ 301
Accounts payable	3,308	4,333
Keylink
Related Party Transaction [Line Items]
Accounts receivable	4,089	5,394
Accounts payable	5,016	4,295
Nuvoton
Related Party Transaction [Line Items]
Accounts payable	1,121	950
JCP
Related Party Transaction [Line Items]
Accounts payable	$ 317	$ 263

Segment Information and Enterprise-Wide Disclosure - Schedule of Net Sales from External Customers and Long Lived Assets by Geographical Areas (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 268,430	$ 285,247	$ 264,224	$ 236,303	$ 232,085	$ 250,694	$ 236,645	$ 222,738	$ 1,054,204	$ 942,162	$ 848,904
Property, plant and equipment, net	459,169				401,988				459,169	401,988	439,340
Total assets	1,488,673				1,528,552				1,488,673	1,528,552	1,598,827
Operating Segments
Segment Reporting Information [Line Items]
Net sales									1,315,688	1,162,393	1,102,064
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales									(261,484)	(220,231)	(253,160)
Asia
Segment Reporting Information [Line Items]
Net sales									839,796	757,649	675,545
Property, plant and equipment, net	390,850				329,587				390,850	329,587	362,186
Total assets	1,061,686				948,923				1,061,686	948,923	969,352
Asia \| Operating Segments
Segment Reporting Information [Line Items]
Net sales									968,720	895,608	793,960
Asia \| Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales									(128,924)	(137,959)	(118,415)
North America
Segment Reporting Information [Line Items]
Net sales									100,356	87,408	82,918
Property, plant and equipment, net	44,523				57,145				44,523	57,145	58,152
Total assets	230,997				400,472				230,997	400,472	463,967
North America \| Operating Segments
Segment Reporting Information [Line Items]
Net sales									171,964	109,442	143,800
North America \| Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales									(71,608)	(22,034)	(60,882)
Europe
Segment Reporting Information [Line Items]
Net sales									114,052	97,105	90,441
Property, plant and equipment, net	23,796				15,256				23,796	15,256	19,002
Total assets	$ 195,990				$ 179,157				195,990	179,157	165,508
Europe \| Operating Segments
Segment Reporting Information [Line Items]
Net sales									175,004	157,343	164,304
Europe \| Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales									$ (60,952)	$ (60,238)	$ (73,863)

Segment Information and Enterprise-Wide Disclosure - Schedule of Net Sales by Countries (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales	$ 268,430	$ 285,247	$ 264,224	$ 236,303	$ 232,085	$ 250,694	$ 236,645	$ 222,738	$ 1,054,204	$ 942,162	$ 848,904
Percentage of net sales									100.00%	100.00%	100.00%
China
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales									$ 593,098	$ 548,015	$ 507,783
Percentage of net sales									56.00%	58.00%	60.00%
United States
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales									$ 86,276	$ 79,869	$ 76,870
Percentage of net sales									8.00%	8.00%	9.00%
Korea
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales									$ 65,849	$ 60,672	$ 66,605
Percentage of net sales									6.00%	6.00%	8.00%
Germany
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales									$ 74,303	$ 61,415	$ 57,036
Percentage of net sales									7.00%	7.00%	7.00%
Singapore
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales									$ 58,570	$ 48,464	$ 51,742
Percentage of net sales									6.00%	5.00%	6.00%
Taiwan
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales									$ 67,399	$ 59,087	$ 30,127
Percentage of net sales									6.00%	6.00%	4.00%
All Others
Segment Reporting Revenue Reconciling Item [Line Items]
Net sales									$ 108,709	$ 84,640	$ 58,741
Percentage of net sales									11.00%	10.00%	6.00%

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments And Contingencies [Line Items]
Lease Expiration Date	Dec. 31, 2024
Operating Leases, Rent Expense, Net	$ 10.4	$ 10.5	$ 10.1
Purchase Commitments	23.5
Equity Investment Obligation \| Chengdu
Commitments And Contingencies [Line Items]
Purchase obligation in 2018	50.0
Purchase obligation in 2019	25.0
Purchase obligation in 2020	25.0
Capital Investment Obligation \| Chengdu
Commitments And Contingencies [Line Items]
Purchase obligation in 2018	62.0
Purchase obligation in 2019	25.0
Purchase obligation in 2020	$ 29.0

Commitments and Contingencies - Commitments (Future Minimum Payment) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2018	$ 9,187
2019	7,662
2020	5,642
2021	3,931
2022	3,365
Thereafter	2,068
Operating Leases, Future Minimum Payment, Total	$ 31,855

Commitments and Contingencies - Summary of Land Right Leases (Details)	12 Months Ended
	Dec. 31, 2017
Chengdu, China
Commitments And Contingencies [Line Items]
Land right lease term	50 years
Land Right Lease, Expiration Year	2061
Shanghai, China
Commitments And Contingencies [Line Items]
Land right lease term	50 years
Land Right Lease, Expiration Year	2056
Shandong, China
Commitments And Contingencies [Line Items]
Land right lease term	50 years
Land Right Lease, Expiration Year	2058
Shanghai 1, China
Commitments And Contingencies [Line Items]
Land right lease term	50 years
Land Right Lease, Expiration Year	2058
Yangzhou, China
Commitments And Contingencies [Line Items]
Land right lease term	50 years
Land Right Lease, Expiration Year	2065

Derivative Financial Instruments - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Objectives for using derivative instruments	The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company primarily uses interest rate swaps, including interest rate collars, as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount.
Net derivative gain will be reclassified from AOCI into net income	$ 500,000
Fair value of derivatives in net asset position	3,900,000	$ 2,300,000
Posted collateral related to agreements	0	0
Foreign Currency Forward Contracts
Derivative [Line Items]
Fair value of foreign exchange hedges	0
Total notional amount of foreign exchange contracts	$ 87,600,000	$ 0

- Definition

Description of the reasons for holding or issuing derivative instruments and nonderivative hedging instruments. Includes discussion of the objectives for holding or issuing derivative instruments, the context needed to understand those objectives, and the strategies for achieving those objectives. The description generally distinguishes between derivative and nonderivative instruments by the types of hedging relationships and between those instruments used for risk management purposes and those used for other purposes. Information about those instruments is disclosed in the context of each instrument's primary underlying risk exposure (for example, interest rate, credit, foreign exchange rate, interest rate and foreign exchange rate, or overall price).

+ References + Details

Derivative Financial Instruments - Summary of Outstanding Foreign Currency Forward Contracts (Details) - Foreign Currency Forward Contracts	12 Months Ended
	Dec. 31, 2017 USD ($) € / £ € / $ £ / $ $ / ¥ $ / ¥ $ / TWD	Dec. 31, 2016 USD ($)
Derivative [Line Items]
Notional Amount	$ 87,600,000	$ 0
Derivative One \| Cash Flow Hedges \| Non-designated
Derivative [Line Items]
Notional Amount	$ 2,494,000
Effective Date	Dec. 31, 2017
Maturity Date	Dec. 31, 2017
Index	EUR/GPB
Weighted Average Strike Rate \| € / £	1.2009
Derivative Two \| Cash Flow Hedges \| Non-designated
Derivative [Line Items]
Notional Amount	$ 10,514,000
Effective Date	Dec. 31, 2017
Maturity Date	Dec. 31, 2017
Index	EUR/USD
Weighted Average Strike Rate \| € / $	1.2009
Derivative Three \| Cash Flow Hedges \| Non-designated
Derivative [Line Items]
Notional Amount	$ 10,612,000
Effective Date	Dec. 31, 2017
Maturity Date	Dec. 31, 2017
Index	GPB/USD
Weighted Average Strike Rate \| £ / $	1.3541
Derivative Four \| Cash Flow Hedges \| Non-designated
Derivative [Line Items]
Notional Amount	$ 31,834,000
Effective Date	Dec. 31, 2017
Maturity Date	Dec. 31, 2017
Index	USD/CNY
Weighted Average Strike Rate \| $ / ¥	6.5343
Derivative Five \| Cash Flow Hedges \| Non-designated
Derivative [Line Items]
Notional Amount	$ 1,594,000
Effective Date	Dec. 31, 2017
Maturity Date	Dec. 31, 2017
Index	USD/JPY
Weighted Average Strike Rate \| $ / ¥	112.35
Derivative Six \| Cash Flow Hedges \| Non-designated
Derivative [Line Items]
Notional Amount	$ 30,594,000
Effective Date	Dec. 31, 2017
Maturity Date	Dec. 31, 2017
Index	USD/TWD
Weighted Average Strike Rate \| $ / TWD	29.406

Derivative Financial Instruments - Summary of Information Related to Number of and Notional Amount of Interest Rate Related Derivative Instruments (Details) - Interest Rate Swaps and Collars - Designated as Hedging Instrument - Cash Flow Hedges	Dec. 31, 2017 USD ($) DerivativeInstrument	Dec. 31, 2016 USD ($) DerivativeInstrument
Derivative [Line Items]
Number of Instruments \| DerivativeInstrument	14	6
Notional Amount \| $	$ 220,000,000	$ 150,000,000

Derivative Financial Instruments - Summary of Fair Value of Interest Rate Related Derivative Financial Instruments and Their Classification on the Consolidated Balance Sheets (Details) - Designated as Hedging Instrument - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Current Assets
Derivative [Line Items]
Fair value of derivative instruments, asset derivatives	$ 486
Other Assets
Derivative [Line Items]
Fair value of derivative instruments, asset derivatives	$ 3,398	$ 3,052
Other Liabilities
Derivative [Line Items]
Fair value of derivative instruments, liability derivatives		$ 735

Derivative Financial Instruments - Summary of Effect of Derivative Financial Instruments on the Consolidated Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Designated as Hedging Instrument \| Interest Rate Swaps and Collars
Derivative Instruments Gain Loss [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative	$ 1,567	$ 2,317
Location of Gain or (Loss) Reclassified from Accumulated OCI into Income	Interest expense
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Net Income	$ 577	$ 112
Not Designated as Hedging Instrument \| Foreign Currency Forward Contracts
Derivative Instruments Gain Loss [Line Items]
Location of Gain or (Loss) Reclassified from Accumulated OCI into Income	Foreign currency (loss) gain, net
Amount of Gain or (Loss) Recognized in Net Income	$ 1,491

Restructuring Costs - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost And Reserve [Line Items]
Assets impairement related to KFAB shut-down	$ 2,211	$ 114	$ 1,672
KFAB Wafer Manufacturing Operations
Restructuring Cost And Reserve [Line Items]
Restructuring activities description	In February 2017, the Company announced its plan to transfer its wafer fabrication operation at KFAB to other Company-owned wafer fabrication plants and external foundries. The Company ceased production operations at KFAB late in third quarter 2017 and vacated and returned the premises in November 2017.
Proceeds from insurance settlement	$ 6,500
Assets impairement related to KFAB shut-down	1,900
Additional asset retirement obligations related to restructuring	1,403
Restructuring costs relating to KFAB shutdown	8,734
KFAB Wafer Manufacturing Operations \| Asset Retirement Obligation Amortization
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	1,400
KFAB Wafer Manufacturing Operations \| Cost of Goods Sold
Restructuring Cost And Reserve [Line Items]
Proceeds from insurance settlement	4,500
KFAB Wafer Manufacturing Operations \| Other Income
Restructuring Cost And Reserve [Line Items]
Proceeds from insurance settlement	$ 2,000

Restructuring Costs - Schedule of Restructuring Costs, Recorded in Restructuring Expense in Condensed Consolidated Statements of Operations, Incurred (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	$ 10,137	$ 12
KFAB Wafer Manufacturing Operations
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	10,137
KFAB Wafer Manufacturing Operations \| Early Termination of Supply Contract
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	1,985
KFAB Wafer Manufacturing Operations \| Asset Retirement Obligation
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	1,403
KFAB Wafer Manufacturing Operations \| Retention Costs
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	3,158
KFAB Wafer Manufacturing Operations \| Cost of Equipment Relocation, Shutdown Cost and Other
Restructuring Cost And Reserve [Line Items]
Restructuring costs relating to KFAB shutdown	$ 3,591

Restructuring Costs - Schedule of Costs Accrued Related to Restructuring (Details) - KFAB Wafer Manufacturing Operations $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Restructuring Cost And Reserve [Line Items]
Costs accrued	$ 8,734
Restructuring costs paid	(7,430)
Balance at December 31, 2017	1,304
Early Contract Termination
Restructuring Cost And Reserve [Line Items]
Costs accrued	1,985
Restructuring costs paid	(1,985)
Retention Costs
Restructuring Cost And Reserve [Line Items]
Costs accrued	3,158
Restructuring costs paid	(2,499)
Balance at December 31, 2017	659
Equipment Relocation, Shutdown Cost and Other
Restructuring Cost And Reserve [Line Items]
Costs accrued	3,591
Restructuring costs paid	(2,946)
Balance at December 31, 2017	$ 645

Restructuring Costs - Schedule of Asset Retirement Obligation Related to Restructuring (Details) - KFAB Wafer Manufacturing Operations $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Restructuring Cost And Reserve [Line Items]
Asset retirement obligation, January 1, 2017	$ 486
Accrual of additional asset retirement obligation	1,403
Amount paid	(1,500)
Asset retirement obligation, December 31, 2017	$ 389

Business Combination - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Nov. 24, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Additional interest expense included in unaudited proforma consolidated results		$ 13,448	$ 13,257	$ 4,232
Additional income tax expense benefit included in unaudited proforma consolidated results		$ 62,325	$ 6,558	14,082
Pericom
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		Nov. 24, 2015
Business Acquisition, Cost of Acquired Entity, Description of Purchase Price Components		we completed our acquisition of Pericom Semiconductor Corporation (“Pericom”) pursuant to the Agreement and Plan of Merger dated as of September 2, 2015 (the “Merger Agreement”), as amended on November 6, 2015, by Amendment No. 1 (the “Merger Agreement Amendment”). Under the Merger Agreement and the Merger Agreement Amendment and in accordance with the General Corporation Law of the State of California (1) PSI Merger Sub, Inc., a California corporation and wholly-owned subsidiary of the Company, was merged with and into Pericom, with Pericom continuing as the surviving corporation and a wholly-owned subsidiary of the Company, and (2) each outstanding share of common stock, without par value, of Pericom (other than shares owned by Pericom or certain of its affiliates or shares held by Pericom shareholders who have perfected their appraisal rights in accordance with applicable California law) was automatically converted into the right to receive $17.75 in cash per share, without interest. The aggregate consideration was approximately $403.2 million including the value of Pericom equity awards paid out or converted to Diodes equity awards pursuant to the Merger Agreement and Merger Agreement Amendment
Exchange rights value of shares	$ 17.75
Business acquisition aggregate consideration	$ 403,174
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual				14,600
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual				(1,000)
Business Acquisition, Pro Forma Information, Description		The table below sets for the unaudited pro forma consolidated results of operations for the years ended December 31, 2015 and December 31, 2014 as if the acquisition of Pericom had occurred at January 1, 2014. The unaudited pro forma consolidated results of operations do not purport to be indicative of the results that would have been obtained if the above acquisition had actually occurred as of the dates indicated or of those results that may be obtained in the future. These unaudited pro forma consolidated results of operations were derived, in part, from the historical consolidated financial statements of Pericom and other available information and assumptions believed to be reasonable under the circumstances.
Acquisition related costs excluded in unaudited proforma consolidated results				10,000
Cost of restricted stock grants and change in control agreements excluded in unaudited proforma consolidated results				8,000
Additional amortization included in unaudited proforma consolidated results				12,000
Additional interest expense included in unaudited proforma consolidated results				11,000
Additional income tax expense benefit included in unaudited proforma consolidated results				$ 1,000

Business Combination - Schedule of Business Acquisitions by Acquisition (Details) - Pericom $ in Thousands	Nov. 24, 2015 USD ($)
Business Acquisition [Line Items]
Purchase price (cost of shares)	$ 4,680
Total purchase price	403,174
Vested Stock Awards
Business Acquisition [Line Items]
Cash consideration	7,371
Shares Outstanding
Business Acquisition [Line Items]
Cash consideration	$ 391,123

Business Combination - Business Acquisition Pro Forma Information (Details) - Pericom $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares
Business Acquisition [Line Items]
Net revenues \| $	$ 960,019
Net income attributable to common stockholders \| $	$ 40,180
Earnings per share—Basic \| $ / shares	$ 0.82
Earnings per share—Diluted \| $ / shares	$ 0.80

Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Net sales	$ 268,430	$ 285,247	$ 264,224	$ 236,303	$ 232,085	$ 250,694	$ 236,645	$ 222,738	$ 1,054,204	$ 942,162	$ 848,904
Gross profit	96,379	96,347	90,139	73,911	67,263	80,623	74,817	64,220	356,776	286,923	248,583
Net income (loss) attributable to common shareholders	$ (30,651)	$ 14,450	$ 13,179	$ 1,217	$ 1,268	$ 10,648	$ 5,752	$ (1,733)	$ (1,805)	$ 15,935	$ 24,274
Earnings (loss) per share attributable to common shareholders
Basic	$ (0.62)	$ 0.29	$ 0.27	$ 0.03	$ 0.07	$ 0.22	$ 0.12	$ (0.04)	$ (0.04)	$ 0.33	$ 0.50
Diluted	$ (0.62)	$ 0.29	$ 0.26	$ 0.02	$ 0.07	$ 0.21	$ 0.12	$ (0.04)	$ (0.04)	$ 0.32	$ 0.49

Employee Benefit Plans - Plan Assets by major categories (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 134,234
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	7,097
Equity Securities \| UK
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,787
Equity Securities \| Europe Excluding UK
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5,713
Equity Securities \| Japan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,703
Equity Securities \| Pacific Basin Excluding Japan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,372
Equity Securities \| Emerging Markets
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,448
Equity Securities \| North America
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	16,082
Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	27,355
Corporate Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3,682
Others, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5,731
Others, Index Linked Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	203
Absolute Return Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,291
Development REITS
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6,004
Insurance Linked Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,117
Liability Driven Investments
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	45,450
Other
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	199
Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,182
Level 1 \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,182
Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	132,052
Level 2 \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,915
Level 2 \| Equity Securities \| UK
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,787
Level 2 \| Equity Securities \| Europe Excluding UK
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5,713
Level 2 \| Equity Securities \| Japan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	2,703
Level 2 \| Equity Securities \| Pacific Basin Excluding Japan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,372
Level 2 \| Equity Securities \| Emerging Markets
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,448
Level 2 \| Equity Securities \| North America
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	16,082
Level 2 \| Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	27,355
Level 2 \| Corporate Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3,682
Level 2 \| Others, Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5,731
Level 2 \| Others, Index Linked Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	203
Level 2 \| Absolute Return Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,291
Level 2 \| Development REITS
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	6,004
Level 2 \| Insurance Linked Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,117
Level 2 \| Liability Driven Investments
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	45,450
Level 2 \| Other
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 199

Segment Information and Enterprise-Wide Disclosure - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017 Customer
Segment Reporting [Abstract]
Number of customer accounted for 10% or more of net sales	1

Business Combination - Schedule of Business Acquisitions by Acquisition (Parentheticals) (Details) $ in Thousands	Nov. 24, 2015 USD ($)
Pericom \| Vested Stock Awards
Business Acquisition [Line Items]
Cash consideration for vested stock awards, taxes	$ 88