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Document and Entity Information - USD ($)	9 Months Ended
Document and Entity Information - USD ($)	Sep. 29, 2018	Oct. 26, 2018	Jun. 30, 2018
Entity Information [Line Items]
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 29, 2018
Entity Registrant Name	VISHAY INTERTECHNOLOGY INC
Entity Central Index Key	0000103730
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 3,076,000,000
Common Stock [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		132,117,715
Class B Convertible Common Stock [Member]
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		12,097,427

Consolidated Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 928,105	$ 748,032
Short-term investments	135,003	547,136
Accounts receivable, net	395,442	340,027
Inventories:
Finished goods	144,622	127,272
Work in process	197,174	170,319
Raw materials	158,505	132,068
Total inventories	500,301	429,659
Prepaid expenses and other current assets	124,949	130,336
Total current assets	2,083,800	2,195,190
Property and equipment, at cost:
Land	87,062	92,285
Buildings and improvements	616,713	606,168
Machinery and equipment	2,478,521	2,415,769
Construction in progress	90,776	103,058
Allowance for depreciation	(2,364,205)	(2,311,522)
Property, Plant and Equipment, Net, Total	908,867	905,758
Goodwill	147,752	142,742
Other intangible assets, net	67,234	69,754
Other assets	141,981	148,645
Total assets	3,349,634	3,462,089
Current liabilities:
Notes payable to banks	4	4
Trade accounts payable	198,674	222,373
Payroll and related expenses	143,257	135,702
Other accrued expenses	174,689	154,230
Income taxes	45,664	50,226
Total current liabilities	562,288	562,535
Long-term debt less current portion	588,586	370,470
U.S. transition tax payable	154,953	151,200
Deferred income taxes	151,499	336,465
Other liabilities	84,827	75,249
Accrued pension and other postretirement costs	269,610	281,701
Total liabilities	1,811,763	1,777,620
Redeemable convertible debentures	79,186	252,070
Vishay stockholders' equity
Common stock	13,212	13,188
Class B convertible common stock	1,210	1,213
Capital in excess of par value	1,595,092	1,752,506
(Accumulated deficit) retained earnings	(151,404)	(362,254)
Accumulated other comprehensive income (loss)	(1,471)	25,714
Total Vishay stockholders' equity	1,456,639	1,430,367
Noncontrolling interests	2,046	2,032
Total equity	1,458,685	1,432,399
Total liabilities, temporary equity, and equity	$ 3,349,634	$ 3,462,089

Consolidated Condensed Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Consolidated Condensed Statements of Operations [Abstract]
Net revenues	$ 780,972	$ 677,941	$ 2,258,797	$ 1,925,906
Costs of products sold	544,676	487,794	1,589,963	1,400,173
Gross profit	236,296	190,147	668,834	525,733
Selling, general, and administrative expenses	98,198	91,487	303,381	272,540
Restructuring and severance costs	0	3,244	0	5,194
Operating income	138,098	95,416	365,453	247,999
Other income (expense):
Interest expense	(10,813)	(6,938)	(26,862)	(20,804)
Other components of net periodic pension cost	(3,367)	(3,088)	(10,336)	(8,947)
Other	2,890	798	5,440	1,151
Loss on early extinguishment of debt			(17,309)	0
Loss on disposal of equity affiliate			0	(7,060)
Nonoperating Income (Expense), Total	(11,290)	(9,228)	(49,067)	(35,660)
Income before taxes	126,808	86,188	316,386	212,339
Income tax expense	48,737	21,605	72,508	54,398
Net earnings	78,071	64,583	243,878	157,941
Less: net earnings attributable to noncontrolling interests	195	179	539	628
Net earnings attributable to Vishay stockholders	$ 77,876	$ 64,404	$ 243,339	$ 157,313
Basic earnings per share attributable to Vishay stockholders	$ 0.54	$ 0.44	$ 1.69	$ 1.08
Diluted earnings per share attributable to Vishay stockholders	$ 0.51	$ 0.41	$ 1.55	$ 1.01
Weighted average shares outstanding - basic	144,383	145,728	144,364	146,128
Weighted average shares outstanding - diluted	152,946	156,701	156,702	155,626
Cash dividends per share	$ 0.0850	$ 0.0625	$ 0.2375	$ 0.1875

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Consolidated Statements of Comprehensive Income [Abstract]
Net earnings	$ 78,071	$ 64,583	$ 243,878	$ 157,941
Other comprehensive income (loss), net of tax
Pension and postretirement actuarial items	1,670	1,292	4,852	4,843
Foreign currency translation adjustment	4,277	28,149	(30,236)	98,965
Unrealized gain (loss) on available-for-sale securities	0	220	0	1,002
Other comprehensive income (loss)	5,947	29,661	(25,384)	104,810
Comprehensive income (loss)	84,018	94,244	218,494	262,751
Less: comprehensive income attributable to noncontrolling interests	195	179	539	628
Comprehensive income (loss) attributable to Vishay stockholders	$ 83,823	$ 94,065	$ 217,955	$ 262,123

Consolidated Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Operating activities
Net earnings	$ 243,878	$ 157,941
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	121,888	121,319
(Gain) loss on disposal of property and equipment	(2,216)	(106)
Accretion of interest on convertible debentures	6,966	3,703
Inventory write-offs for obsolescence	17,059	12,157
Deferred income taxes	(12,348)	9,115
Non-cash loss on disposal of equity affiliate	0	7,060
Loss on early extinguishment of debt	17,309	0
Other	13,021	6,531
U.S. transition tax (net)	(14,400)	0
Repatriation taxes	(156,767)	0
Net change in operating assets and liabilities, net of effects of businesses acquired	(125,499)	(71,875)
Net cash provided by operating activities	108,891	245,845
Investing activities
Capital expenditures	(126,391)	(84,790)
Proceeds from sale of property and equipment	8,455	1,484
Purchase of businesses, net of cash acquired	(14,880)	0
Purchase of short-term investments	(172,732)	(598,937)
Maturity of short-term investments	577,524	610,573
Other investing activities	(1,608)	(6,663)
Net cash provided by (used in) investing activities	270,368	(78,333)
Financing activities
Proceeds from long-term borrowings	600,000	0
Issuance costs	(15,621)	0
Repurchase of convertible debentures	(584,991)	0
Net proceeds (payments) on revolving credit lines	(150,000)	(5,000)
Common stock repurchase	0	(37,564)
Net changes in short-term borrowings	0	22
Proceeds from stock options exercised	0	1,260
Distributions to noncontrolling interests	(525)	(1,140)
Acquisition of noncontrolling interests	0	(4,100)
Cash withholding taxes paid when shares withheld for vested equity awards	(2,297)	(1,971)
Other financing activities	0	(1,255)
Net cash provided by (used in) financing activities	(187,685)	(77,076)
Effect of exchange rate changes on cash and cash equivalents	(11,501)	13,168
Net increase (decrease) in cash and cash equivalents	180,073	103,604
Cash and cash equivalents at beginning of period	748,032	471,781
Cash and cash equivalents at end of period	928,105	575,385
Common Stock [Member]
Financing activities
Dividends and Interest Paid	(31,378)	(25,054)
Class B Convertible Common Stock [Member]
Financing activities
Dividends and Interest Paid	$ (2,873)	$ (2,274)

Consolidated Condensed Statement of Equity - USD ($) $ in Thousands	Common Stock	Class B Convertible Common Stock [Member]	Capital In Excess of Par Value	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Total Vishay Stockholders' Equity	Noncontrolling Interest	Total
Cumulative effect of accounting change for adoption of ASU	$ 0	$ 0	$ 0	$ 2,210	$ 0	$ 2,210	$ 0	$ 2,210
Balance at December 31, 2017 at Dec. 31, 2015	13,546	1,213	2,058,492	(319,448)	(131,327)	1,622,476	5,567	1,628,043
Net earnings	0	0	0	48,792	0	48,792	581	49,373
Other comprehensive income (loss)	0	0	0	0	36,675	36,675	0	36,675
Distributions to noncontrolling interests	0	0	0	0	0	0	(707)	(707)
Share repurchase	(175)	0	(22,984)	0	0	(23,159)	0	(23,159)
Temporary equity reclassification	0	0	(88,659)	0	0	(88,659)	0	(88,659)
Restricted stock issuances	11	0	(553)	0	0	(542)	0	(542)
Dividends declared	0	0	36	(36,761)	0	(36,725)	0	(36,725)
Stock compensation expense	0	0	6,380	0	0	6,380	0	6,380
Stock options exercised	3	0	353	0	0	356	0	356
Tax effects of stock plan	0	0	(77)	0	0	(77)	0	(77)
Balance at Dec. 31, 2016	13,385	1,213	1,952,988	(305,207)	(94,652)	1,567,727	5,441	1,573,168
Cumulative effect of accounting change for adoption of ASU	0	0	0	386	0	386	0	386
Net earnings	0	0	0	(20,344)	0	(20,344)	784	(19,560)
Other comprehensive income (loss)	0	0	0	0	120,366	120,366	0	120,366
Distributions to noncontrolling interests	0	0	0	0	0	0	(1,140)	(1,140)
Acquisition of noncontrolling interests	0	0	(1,047)	0	0	(1,047)	(3,053)	(4,100)
Share repurchase	(225)	0	(39,719)	0	0	(39,944)	0	(39,944)
Temporary equity reclassification	0	0	(163,411)	0	0	(163,411)	0	(163,411)
Restricted stock issuances	20	0	(1,991)	0	0	(1,971)	0	(1,971)
Dividends declared	0	0	40	(37,089)	0	(37,049)	0	(37,049)
Stock compensation expense	0	0	4,394	0	0	4,394	0	4,394
Stock options exercised	8	0	1,252	0	0	1,260	0	1,260
Balance at Dec. 31, 2017	13,188	1,213	1,752,506	(362,254)	25,714	1,430,367	2,032	1,432,399
Cumulative effect of accounting change for adoption of ASU	0	0	0	1,801	(1,801)	0	0	0
Net earnings	0	0	0	243,339	0	243,339	539	243,878
Other comprehensive income (loss)	0	0	0	0	(25,384)	(25,384)	0	(25,384)
Conversions from Class B to common stock	3	(3)	0	0	0	0	0	0
Distributions to noncontrolling interests	0	0	0	0	0	0	(525)	(525)
Acquisition of noncontrolling interests								0
Temporary equity reclassification	0	0	2,137	0	0	2,137	0	2,137
Restricted stock issuances	21	0	(2,318)	0	0	(2,297)	0	(2,297)
Dividends declared	0	0	39	(34,290)	0	(34,251)	0	(34,251)
Stock compensation expense	0	0	4,039	0	0	4,039	0	4,039
Issuance of convertible debentures	0	0	85,262	0	0	85,262	0	85,262
Repurchase of convertible debentures	0	0	(246,573)	0	0	(246,573)	0	(246,573)
Balance at Sep. 29, 2018	$ 13,212	$ 1,210	$ 1,595,092	$ (151,404)	$ (1,471)	$ 1,456,639	$ 2,046	$ 1,458,685

Consolidated Condensed Statement of Equity (Parenthetical) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 29, 2018	Dec. 31, 2017	Dec. 31, 2016
Consolidated Condensed Statement of Equity [Abstract]
Restricted stock issuances (in shares)	211,328	200,688	110,825
Stock repurchase (in shares)		2,250,236	1,752,454
Stock options exercised (in shares)		77,334	27,619
Conversion of Class B shares	31,800
Common Stock, Dividends, Per Share, Cash Paid	$ 0.2375	$ 0.2550	$ 0.2500

Basis of Presentation

9 Months Ended

Sep. 29, 2018

New Accounting Pronouncements [Abstract]

Basis of Presentation

Note 1 – Basis of Presentation

The accompanying unaudited consolidated condensed financial statements of Vishay Intertechnology, Inc. ("Vishay" or the "Company") have been prepared in accordance with the instructions to Form 10-Q and therefore do not include all information and footnotes necessary for presentation of financial position, results of operations, and cash flows required by accounting principles generally accepted in the United States ("GAAP") for complete financial statements. The information furnished reflects all normal recurring adjustments which are, in the opinion of management, necessary for a fair summary of the financial position, results of operations, and cash flows for the interim periods presented. The financial statements should be read in conjunction with the consolidated financial statements filed with the Company's Annual Report on Form 10-K for the year ended December 31, 2017. The results of operations for the fiscal quarter and nine fiscal months ended September 29, 2018 are not necessarily indicative of the results to be expected for the full year.

The Company reports interim financial information for 13-week periods beginning on a Sunday and ending on a Saturday, except for the first fiscal quarter, which always begins on January 1, and the fourth fiscal quarter, which always ends on December 31. The four fiscal quarters in 2018 end on March 31, 2018, June 30, 2018, September 29, 2018, and December 31, 2018, respectively. The four fiscal quarters in 2017 ended on April 1, 2017, July 1, 2017, September 30, 2017, and December 31, 2017, respectively.

Recently Adopted Accounting Guidance

In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU is the result of a convergence project between the FASB and the International Accounting Standards Board to clarify the principles for recognizing revenue and to develop a common revenue standard for GAAP and International Financial Reporting Standards. The ASU removes inconsistencies and weaknesses in revenue requirements; provides a more robust framework for addressing revenue issues; improves comparability of revenue recognition practices across entities, industries, jurisdictions, and capital markets; provides more useful information to users of financial statements through expanded disclosure requirements; and simplifies the preparation of financial statements by reducing the number of requirements to which an entity must refer. The Company retrospectively adopted the ASU on January 1, 2018. The adoption of the ASU did not have a material impact on the Company's results of operations. See Note 2 and "Changes in Accounting Policies" below.

In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The ASU enhances the reporting model for financial instruments by addressing certain aspects, including requiring equity investments to be measured at fair value with changes in fair value recognized in net income; simplifying the impairment assessment of equity investments without readily determinable fair values; eliminating the requirement to disclose the method and significant assumptions used to estimate the disclosed fair value of financial instruments measured at amortized cost; and requiring the use of the exit price notion for fair value measurements of financial instruments for disclosure purposes. The Company adopted the ASU on January 1, 2018. The Company recognized a cumulative-effect adjustment to January 1, 2018 retained earnings (accumulated deficit) of $1,801 for the cumulative change in fair value of available-for-sale equity investments previously recognized in other comprehensive income. The adoption of the ASU did not have a material impact on the Company's results of operations.

In March 2017, the FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The ASU amends the income statement presentation requirements of net periodic benefit cost of defined benefit pension and other postretirement plans. The Company retrospectively adopted the ASU on January 1, 2018. The adoption of the ASU did not have a material impact on the Company's results of operations. See "Changes in Accounting Policies" below.

Recently Issued Accounting Guidance

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The ASU is the result of a project between the FASB and the International Accounting Standards Board to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Upon adoption of the ASU, the Company will recognize lease assets and liabilities for its operating leases which are not currently reported on its consolidated balance sheets. The ASU is effective for the Company for interim and annual periods beginning on or after January 1, 2019, with the ability to early adopt. The Company is currently evaluating the effect of the ASU on its lease contracts.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU replaces the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The ASU is effective for the Company for interim and annual periods beginning on or after January 1, 2020, with the ability to early adopt for interim and annual periods beginning on or after January 1, 2019. The Company is currently evaluating the effect of the ASU on its financial assets measured at amortized cost.

Changes in Accounting Policies

Except for the changes described in "Recently Adopted Accounting Guidance" above and in this section below, the Company has consistently applied the accounting policies described in its Note 1 to its audited consolidated financial statement included in its annual report on Form 10-K for the year ended December 31, 2017, to all periods presented in these consolidated condensed financial statements.

Revenue Recognition

The Company adopted ASU 2014-09 as of January 1, 2018 using the full retrospective method. As a result, the Company has changed its accounting policy for revenue recognition. The details of significant changes and quantitative impact of the changes are disclosed below.

Service-type warranty performance obligations

ASU 2014-09 introduces the concept of service-type warranties, which represent separate performance obligations. Upon adoption of ASU 2014-09, the Company considers its warranty obligations as service-type warranties and allocates a portion of the estimated consideration to be received from the related contract to the service-type warranty performance obligation and recognizes the related revenue over the warranty period. The impact of accounting for service-type warranties as separate performance obligations was not significant in the retrospective adoption period and is included in the tables below. See further discussion of the warranty obligations in Note 2.

Custom products

The Company previously recognized revenue when the sales process was completed, which generally occurred when the product was delivered and risk of loss was transferred to the customer. Upon adoption of ASU 2014-09, the Company analyzes its contractual arrangements to determine whether the promise in the contract to construct and transfer goods to the customer is a performance obligation that will be satisfied over time or at a point in time. When the Company's performance does not create an asset with an alternative use to the Company and the Company has an enforceable right to payment for performance completed to date, the Company transfers control of a good or service over time and, therefore, satisfies a performance obligation and recognizes revenue over time. The Company has a limited number of contracts for custom products that meet the criteria to recognize revenue over time. The dollar amount of these custom products did not materially change during the retrospective adoption period. The Company recorded a cumulative-effect adjustment of $2,210 to January 1, 2016 retained earnings (accumulated deficit) and recorded adjustments to its consolidated balance sheets due to the impact of recognizing revenue for certain custom products over time rather than at a point in time.

ASU 2014-09 provides several transition practical expedients. The Company has not restated completed contracts that begin and end in the same annual reporting period; used the transaction price at the date the contract was completed rather than estimating variable consideration amounts in the comparative reporting periods; has not disclosed the amount of the transaction price allocated to the remaining performance obligations and an explanation of when the Company expects to recognize the amount as revenue for the reporting periods presented prior to January 1, 2016; and has not retrospectively restated the contract for modifications made prior to January 1, 2016 and instead reflected the aggregate effect of all modifications when identifying the satisfied and unsatisfied performance obligations, determining the transaction price and allocating the transaction price pursuant to the transition practical expedients available.

Pension and Other Postretirement Benefits

The Company retrospectively adopted ASU No. 2017-07 as of January 1, 2018. As a result, the Company has changed its accounting policy for pension and other postretirement benefits costs as detailed below.

ASU 2017-07 amends the income statement presentation requirements of net periodic benefit cost of defined benefit pension and other postretirement plans. The service cost component of net periodic pension cost is recorded in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period, and other components of net periodic pension cost are included on a separate line within other income (expense). The Company reclassified net benefit costs other than the current service component previously reported as cost of goods sold and selling, general, and administrative expenses to other expenses for each quarter in the retrospective adoption period in the table below. The Company also reclassified the $79,321 U.S. pension settlement charges recorded for the year ended December 31, 2016 to other expenses. See the impact of this change in the tables below.

The retrospective adoption of ASUs 2014-09 and 2017-07 did not impact net earnings (loss) attributed to Vishay stockholders. See the combined impact of the retrospective adoption in the tables below:

Fiscal quarters ended
	April 1, 2017									July 1, 2017									September 30, 2017									December 31, 2017
	As Reported			Adjustments			Recast			As Reported			Adjustments			Recast			As Reported			Adjustments			Recast			As Reported			Adjustments			Recast

Net revenues	$	606,258		$	(1,457	)	$	604,801		$	644,892		$	(1,728	)	$	643,164		$	677,883		$	58		$	677,941		$	674,489		$	(1,027	)	$	673,462
Costs of products sold		445,383			(2,331	)		443,052			471,929			(2,602	)		469,327			488,610			(816	)		487,794			497,988			(1,902	)		496,086
Gross profit		160,875			874			161,749			172,963			874			173,837			189,273			874			190,147			176,501			875			177,376
Operating income		64,688			2,890			67,578			82,036			2,969			85,005			92,328			3,088			95,416			72,536			3,470			76,006
Total other income (expense)		(14,246	)		(2,890	)		(17,136	)		(6,327	)		(2,969	)		(9,296	)		(6,140	)		(3,088	)		(9,228	)		(5,511	)		(3,470	)		(8,981	)
Income before taxes		50,442			-			50,442			75,709			-			75,709			86,188			-			86,188			67,025			-			67,025
Income tax expense		13,493			-			13,493			19,300			-			19,300			21,605			-			21,605			244,526			-			244,526
Net earnings (loss)		36,949			-			36,949			56,409			-			56,409			64,583			-			64,583			(177,501	)		-			(177,501	)
Less: net earnings attributable to noncontrolling interests		230			-			230			219			-			219			179			-			179			156			-			156
Net earnings (loss) attributable to Vishay stockholders	$	36,719		$	-		$	36,719		$	56,190		$	-		$	56,190		$	64,404		$	-		$	64,404		$	(177,657	)	$	-		$	(177,657	)

	Years ended
	December 31, 2016									December 31, 2017
	As Reported			Adjustments			Recast			As Reported			Adjustments			Recast

Net revenues	$	2,323,431		$	(6,103	)	$	2,317,328		$	2,603,522		$	(4,154	)	$	2,599,368
Costs of products sold		1,753,648			(10,142	)		1,743,506			1,903,910			(7,651	)		1,896,259
Gross profit		569,783			4,039			573,822			699,612			3,497			703,109
Operating income		101,717			95,341			197,058			311,588			12,417			324,005
Total other income (expense)		(7,501	)		(95,341	)		(102,842	)		(32,224	)		(12,417	)		(44,641	)
Income before taxes		94,216			-			94,216			279,364			-			279,364
Income tax expense		44,843			-			44,843			298,924			-			298,924
Net earnings (loss)		49,373			-			49,373			(19,560	)		-			(19,560	)
Less: net earnings attributable to noncontrolling interests		581			-			581			784			-			784
Net earnings (loss) attributable to Vishay stockholders	$	48,792		$	-		$	48,792		$	(20,344	)	$	-		$	(20,344	)

Reclassifications

In addition to the changes due to the retrospective adoption of certain aspects of new accounting guidance described above, certain prior period amounts have been reclassified to conform to the current financial statement presentation.

Revenue Recognition Policies

9 Months Ended

Sep. 29, 2018

Revenue Recognition [Abstract]

Revenue Recognition [Text Block]

Note 2 – Revenue Recognition

As of January 1, 2018, the Company recognizes revenue from contracts with customers in accordance with ASU 2014-09. The Company has framework agreements with many of its customers that contain the terms and conditions of future sales, but do not create enforceable rights or obligations. Per ASU 2014-09, the Company's contracts are the combined purchase orders and the terms and conditions contained within such framework agreements.

Payment terms for the Company's sales are generally less than sixty days. Substantially all of the Company's receivables are collected within twelve months of the transfer of products to the customer and the Company expects this to continue going forward. The Company applies the practical expedient within ASU 2014-09 to all of its contracts with payment terms less than or equal to twelve months and does not recognize a financing component of the transaction price.

Revenue is measured based on the consideration specified in contracts with customers, and excludes any sales incentives and amounts collected on behalf of third parties. The Company recognizes revenue when it satisfies its performance obligations.

The Company's contracts contain two performance obligations: delivery of products and warranty protection. The Company does not sell separate, enhanced, or extended warranty coverage, but through its customary business practices, the Company has created implied service-type warranties, which are accounted for as separate performance obligations. Revenue is allocated between these two performance obligations and recognized as the obligations are satisfied. The allocation of revenue to warranty protection is based on an estimate of expected cost plus margin. The delivery of products performance obligation is satisfied and product sales revenue is recognized when the customer takes control of the products. Warranty revenue is deferred and the warranty protection performance obligation is satisfied and revenue is recognized over the warranty period, which is typically less than twenty-four months from sale to end customer. The warranty deferred revenue liability is recorded within Other Accrued Expenses and Other Liabilities on the accompanying consolidated condensed balance sheets. The deferred revenue balance associated with the service-type warranty performance obligations and the components that comprise the change in the deferred revenue balance are not significant.

The Company has a broad line of products that it sells to original equipment manufacturers ("OEMs"), electronic manufacturing services ("EMS") companies, which manufacture for OEMs on an outsourcing basis, and independent distributors that maintain large inventories of electronic components for resale to OEMs and EMS companies.

The Company has and will continue to recognize revenue on sales to distributors when the distributor takes control of the products ("sold-to" model). The Company has agreements with distributors that allow distributors a limited credit for unsaleable products, which it terms a "scrap allowance." Consistent with industry practice, the Company also has a "stock, ship and debit" program whereby it considers requests by distributors for credits on previously purchased products that remain in distributors' inventory, to enable the distributors to offer more competitive pricing. In addition, the Company has contractual arrangements whereby it provides distributors with protection against price reductions initiated by the Company after product is sold by the Company to the distributor and prior to resale by the distributor.

The Company recognizes the estimated variable consideration to be received as revenue and records a related accrued expense for the consideration not expected to be received, based upon its estimate of product returns, scrap allowances, "stock, ship and debit" credits, and price protection credits that will be attributable to sales recorded through the end of the period. The Company makes these estimates based upon sales levels to its distributors during the period, inventory levels at the distributors, current and projected market conditions, and historical experience under the programs. While the Company utilizes a number of different methodologies to estimate the accruals, all of the methodologies take into account sales levels to distributors during the relevant period, inventory levels at the distributors, current and projected market trends and conditions, recent and historical activity under the relevant programs, changes in program policies, and open requests for credits. These procedures require the exercise of significant judgments. The Company believes that it has a reasonable basis to estimate future credits under the programs.

Distributor sales accrual activity is shown below:

	Fiscal quarters ended						Nine fiscal months ended						Years Ended December 31,
	September 29, 2018			September 30, 2017			September 29, 2018			September 30, 2017			2017			2016
Beginning balance	$	38,032		$	35,733		$	36,680		$	34,479		$	34,479		$	32,487
Sales allowances		27,986			22,421			77,539			67,191			89,009			86,896
Credits issued		(29,293	)		(28,116	)		(77,091	)		(71,638	)		(87,403	)		(85,341	)
Foreign currency		103			384			(300	)		390			595			437
Ending balance	$	36,828		$	30,422		$	36,828		$	30,422		$	36,680		$	34,479

The Company pays commissions to external sales representatives on a per-sale basis. The Company applies the practical expedient available within ASU 2014-09 to all commissions paid as the future amortization period of the asset that the Company otherwise would have recognized is one year or less. Accordingly, these commissions are expensed as incurred. Internal staff are not paid commissions.

The Company has elected to account for shipping and handling as activities to fulfill the promise to transfer the product even if the shipping and handling activities are performed after the customer obtains control. The Company does not evaluate whether shipping and handling activities are promised services to its customers. If control transfers and revenue is recognized for the related products before the shipping and handling activities occur, the related costs of those shipping and handling activities is accrued. The Company applies this accounting policy election consistently to similar types of transactions.

See disaggregated revenue information in Note 10.

Acquisition Activities	9 Months Ended
Acquisition Activities	Sep. 29, 2018
Acquisition and Divestiture Activities [Abstract]
Acquisition and Divestiture Activities	Note 3 – Acquisition Activities As part of its growth strategy, the Company seeks to expand through targeted acquisitions of other manufacturers of electronic components that have established positions in major markets, reputations for product quality and reliability, and product lines with which the Company has substantial marketing and technical expertise. On February 8, 2018, the Company acquired substantially all of the assets and liabilities of UltraSource, Inc., a U.S.-based, privately-held thin film circuit and thin film interconnect manufacturer, for $13,596. Based on an estimate of their fair values, the Company allocated $6,500 of the purchase price to definite-lived intangible assets. After allocating the purchase price to the assets acquired and liabilities assumed based on an estimation of their fair values at the date of acquisition, the Company recorded goodwill of $4,227 related to this acquisition. The results and operations of this acquisition have been included in the Resistors & Inductors segment since February 8, 2018. The inclusion of this acquisition did not have a material impact on the Company's consolidated results for the fiscal quarter or nine fiscal months ended September 29, 2018. The goodwill related to this acquisition is included in the Resistors & Inductors reporting unit for goodwill impairment testing. On June 11, 2018, the Company acquired EuroPower Holdings Ltd. ("EuroPower") for $2,939, net of cash acquired. EuroPower is a distributor of electronic components in the United Kingdom. The inclusion of this business did not have a material impact on the Company's consolidated results for the fiscal quarter or nine fiscal months ended September 29, 2018. After allocating the purchase price to the assets acquired and liabilities assumed based on an estimation of their fair values at the date of acquisition, the Company recorded goodwill of $1,068 related to this acquisition. The goodwill related to this acquisition is included in the Resistors & Inductors reporting unit for goodwill impairment testing. Had these acquisitions occurred as of the beginning of the periods presented in these consolidated condensed financial statements, the pro forma statements of operations would not be materially different than the consolidated condensed statements of operations presented. The remaining fluctuation in the goodwill account balance is due to foreign currency translation.

Restructuring and Related Activities

9 Months Ended

Sep. 29, 2018

Restructuring and Related Activities [Abstract]

Restructuring and Related Activities

Note 4 – Restructuring and Related Activities

The Company places a strong emphasis on controlling its costs and combats general price inflation by continuously improving its efficiency and operating performance. When the ongoing cost containment activities are not adequate, the Company takes actions to maintain its cost competitiveness.

The Company incurred significant restructuring costs in its past to reduce its cost structure. Historically, the Company's primary cost reduction technique was through the transfer of production from high-labor-cost countries to lower-labor-cost countries. Since 2013, the Company's cost reduction programs have primarily focused on reducing fixed costs, including selling, general, and administrative expenses. As of December 31, 2017, the Company's restructuring programs were substantially completed.

The following table summarizes restructuring and related expenses which were recognized and reported on a separate line in the accompanying consolidated condensed statements of operations:

	Fiscal quarter ended		Nine fiscal months ended
	September 30, 2017		September 30, 2017
MOSFETs Enhanced Competitiveness Program	$	2,463	$	2,911
Global Cost Reduction Programs		781		2,283
Total	$	3,244	$	5,194

MOSFETs Enhanced Competitiveness Program

Over a period of approximately 2 years and in a series of discrete steps, the manufacture of wafers for a substantial share of products was transferred into a more cost-efficient fab. As a consequence, certain other manufacturing previously occurring in-house was transferred to third-party foundries. This transfer of production was substantially completed by the end of the first fiscal quarter of 2016.

As a result of a review of the financial results and outlook for the Company's MOSFETs segment following the completion of production transfers, the Company determined to implement further cost reductions for the MOSFETs segment. In November 2016, the Company announced an extension of the MOSFETs Enhanced Competitiveness Program. The revised program included various cost reduction initiatives, primarily the transfer of all remaining manufacturing operations at its Santa Clara, California facility to other Vishay facilities or third-party subcontractors.

The following table summarizes the activity to date related to this program:

Expense recorded in 2013	$	2,328
Cash paid		(267	)
Balance at December 31, 2013	$	2,061
Expense recorded in 2014		6,025
Cash paid		(856	)
Balance at December 31, 2014	$	7,230
Expense recorded in 2015		5,367
Cash paid		(426	)
Foreign currency translation		1
Balance at December 31, 2015	$	12,172
Expense recorded in 2016		9,744
Cash paid		(15,686	)
Foreign currency translation		2
Balance at December 31, 2016	$	6,232
Expense recorded in 2017		3,204
Cash paid		(7,173	)
Balance at December 31, 2017	$	2,263
Cash paid		(1,051	)
Balance at September 29, 2018	$	1,212

Severance benefits are generally paid in a lump sum at cessation of employment. The entire liability is considered current and is included in other accrued expenses in the accompanying consolidated condensed balance sheets.

Global Cost Reduction Programs

The global cost reduction programs announced in 2015 included a plan to reduce selling, general, and administrative costs company-wide, and targeted streamlining and consolidation of production for certain product lines within its Capacitors and Resistors & Inductors segments. These programs were substantially implemented as of December 31, 2017.

The following table summarizes the activity to date related to this program:

Expense recorded in 2015	$	13,753
Cash paid		(986	)
Foreign currency translation		(150	)
Balance at December 31, 2015	$	12,617
Expense recorded in 2016		9,918
Cash paid		(16,237	)
Foreign currency translation		(34	)
Balance at December 31, 2016	$	6,264
Expense recorded in 2017		8,069
Cash paid		(7,168	)
Foreign currency translation		500
Balance at December 31, 2017	$	7,665
Cash paid		(2,881	)
Foreign currency translation		(87	)
Balance at September 29, 2018	$	4,697

The following table summarizes the expense recognized by segment related to this program:

	Fiscal quarter ended			Nine fiscal months ended
	September 30, 2017			September 30, 2017
Diodes	$	(13	)	$	-
Optoelectronic Components		-			242
Resistors & Inductors		468			1,403
Capacitors		88			334
Unallocated Selling, General, and Administrative Expenses		238			304
Total	$	781		$	2,283

Severance benefits are generally paid in a lump sum at cessation of employment, though some are being paid in installments. The current portion of the liability is $2,772 and is included in other accrued expenses in the accompanying consolidated condensed balance sheets. The non-current portion of the liability is included in other liabilities in the accompanying consolidated condensed balance sheets.

Income Taxes	9 Months Ended
Income Taxes	Sep. 29, 2018
Income Taxes [Abstract]
Income Taxes	Note 5 – Income Taxes The provision for income taxes consists of provisions for federal, state, and foreign income taxes. The effective tax rates for the periods ended September 29, 2018 and September 30, 2017 reflect the Company's expected tax rate on reported income from continuing operations before income tax and tax adjustments. The Company operates in a global environment with significant operations in various jurisdictions outside the United States. Accordingly, the consolidated income tax rate is a composite rate reflecting the Company's earnings and the applicable tax rates in the various jurisdictions where the Company operates. On December 22, 2017, the Tax Cuts and Jobs Act (the "TCJA") was enacted in the United States. The TCJA represents sweeping changes in U.S. tax law. Among the numerous changes in tax law, the TCJA permanently reduced the U.S. corporate income tax rate to 21% beginning in 2018; imposed a one-time transition tax on deferred foreign earnings; established a partial territorial tax system by allowing a 100% dividends received deduction on qualifying dividends paid by foreign subsidiaries; limited deductions for net interest expense; expanded the U.S. taxation of foreign earned income to include "global intangible low-taxed income" ("GILTI") of foreign subsidiaries; and imposed a base erosion and anti-abuse minimum tax ("BEAT"). The TCJA represents the first significant change in U.S. tax law in over 30 years. As permitted by SAB No. 118, the tax expense recorded in the fourth fiscal quarter of 2017 due to the enactment of the TCJA was considered "provisional," based on reasonable estimates. As further described below, after additional analysis was completed in the second and third fiscal quarters of 2018, the Company identified additional amounts available to be repatriated to the U.S. and additional information regarding the foreign taxes payable and recorded additional provisional tax expense to accrue the incremental foreign income taxes and withholding taxes payable to foreign jurisdiction. The Company is continuing to collect and analyze detailed information about the earnings and profits of its non-U.S. subsidiaries, the related taxes paid, the amounts which could be repatriated, the foreign taxes which may be incurred on repatriation, and the associated impact of these items under the TCJA. The Company may record further adjustments to refine those estimates during the measurement period, as additional analysis is completed. The TCJA transitions the U.S. from a worldwide tax system to a partial territorial tax system. Under previous law, companies could indefinitely defer U.S. income taxation on unremitted foreign earnings. The TCJA imposes a one-time transition tax on deferred foreign earnings of 15.5% for liquid assets and 8% for illiquid assets, payable in defined increments over eight years. As a result of this requirement, the Company recognized provisional tax expense of $215,558 in 2017, and provisionally expects to pay $184,468, net of estimated applicable foreign tax credits, and after utilization of net operating loss, R&D credits, and foreign tax credit carryforwards. As a result of additional analysis completed in the third fiscal quarter of 2018, the Company accrued additional provisional tax expense of $6,214. The first installment of $14,400 was paid in the second fiscal quarter of 2018. These previously deferred foreign earnings may now be repatriated to the United States without additional U.S. federal taxation. However, any such repatriation could incur withholding and other foreign taxes in the source and intervening foreign jurisdictions, and certain U.S. state taxes. Due to the changes in taxation of dividends received from foreign subsidiaries, and also because of the need to finance the payment of the transition tax, the Company made the determination during the fourth fiscal quarter of 2017 that certain unremitted foreign earnings in Israel, Germany, Austria, and France are no longer permanently reinvested, and recorded provisional tax expense of $213,000 to accrue the incremental foreign income taxes and withholding taxes payable to foreign jurisdictions assuming the hypothetical repatriation to the United States of these approximately $1,100,000 of available foreign earnings. As a result of additional analysis completed in the second and third fiscal quarters of 2018, the Company adjusted the amount of foreign unremitted earnings available from Israel, Germany, Austria, and France to approximately $1,200,000, identified additional information regarding the foreign taxes payable, and accrued additional provisional tax expense of $19,282. The Company repatriated approximately $274,000 and approximately $450,000 to the United States, and paid withholding and foreign taxes of $92,093 and $64,674 in the second and third fiscal quarters of 2018, respectively. Substantially all of the amounts repatriated in the second fiscal quarter were used to reduce the outstanding balance of the credit facility (see Note 6) and to repay certain intercompany indebtedness. A portion of the amounts repatriated in the third fiscal quarter were used to eliminate the remaining outstanding balance of the credit facility. After completing these phases of cash repatriation, there is approximately $300,000 of unremitted foreign earnings that the Company has deemed not permanently reinvested and thus has accrued foreign withholding and other taxes. The Company expects to repatriate these remaining amounts at a measured pace over several years, and may decide to ultimately not repatriate some of these amounts. The Company's effective tax rate for the periods ended September 29, 2018 was negatively impacted by certain provisions of the TCJA. The provisions of the TCJA are interrelated and the impact of any specific provision cannot be isolated. The Company operates at a pre-tax loss in the U.S. and the reduction in the federal tax rate reduces the tax benefit recorded. In addition, the inclusion of GILTI income and the limitation on the deductibility of interest expense increased the effective tax rate. The Company has elected to account for GILTI tax in the period in which it is incurred, and therefore did not provide any deferred taxes in the consolidated financial statements at December 31, 2017. BEAT could potentially increase the Company's U.S. federal income tax by disallowing certain otherwise deductible payments from the U.S. to non-U.S. subsidiaries and imposing a minimum tax if greater than the regular tax. The Company expects to be subject to BEAT in 2018 and future periods, but BEAT did not have a material impact on the Company's effective tax rate for the periods ended September 29, 2018. The Company's repurchase of a portion of the outstanding convertible debentures in the second fiscal quarter of 2018 (see Note 6) reduced the Company's expected full year 2018 tax rate. The Company recognized a tax benefit on the pre-tax loss on early extinguishment of debt. The Company also recognized a tax benefit of $33,963 in the second fiscal quarter of 2018 resulting from the extinguishment, reflecting the reduction in deferred tax liabilities related to the special tax attributes of the debentures. Income tax expense for the fiscal quarter and nine fiscal months ended September 29, 2018, includes tax expense of $680 and tax benefits of $7,010 for the periodic remeasurement of the deferred tax liability recorded for the foreign taxes associated with the cash repatriation program described above. Income tax expense for the fiscal quarter and nine fiscal months ended September 30, 2017 included a tax benefit of $892 and $3,100 for the periodic remeasurement of the deferred tax liability recorded for the cash repatriation program that was terminated as a result of the enactment of the TCJA. During the nine fiscal months ended September 29, 2018, the liabilities for unrecognized tax benefits increased by $3,486 on a net basis, due to increases for tax positions taken in the current period and interest, offset by payments and foreign currency effects.

Long-Term Debt

9 Months Ended

Sep. 29, 2018

Long-Term Debt [Abstract]

Long-Term Debt

Note 6 – Long-Term Debt

Long-term debt consists of the following:

	September 29, 2018			December 31, 2017

Credit facility	$	-		$	150,000
Convertible senior debentures, due 2040		22,486			110,412
Convertible senior debentures, due 2041		57,695			56,641
Convertible senior debentures, due 2042		34,268			62,518
Convertible notes, due 2025		491,853			-
Deferred financing costs		(17,716	)		(9,101	)
		588,586			370,470
Less current portion		-			-
	$	588,586		$	370,470

Convertible Senior Notes due 2025

In June 2018, the Company issued $600,000 aggregate principal amount of 2.25% convertible senior notes due 2025 to qualified institutional investors. The Company used the net proceeds from this offering to repurchase $220,000 and $69,060 principal amounts of convertible senior debentures due 2040 and 2042, respectively, as further described below.

GAAP requires an issuer to separately account for the liability and equity components of the instrument in a manner that reflects the issuer's nonconvertible debt borrowing rate when interest costs are recognized in subsequent periods. The resulting discount on the debt is amortized as non-cash interest expense in future periods.

The carrying values of the liability and equity components of the convertible notes are reflected in the Company's consolidated balance sheets as follows:

	Principal amount of the notes		Unamortized discount			Carrying value of liability component		Equity component - net carrying value
September 29, 2018
Due 2025	$	600,000		(108,147	)	$	491,853	$	85,262

Interest is payable on the convertible notes due 2025 semi-annually in arrears on June 15 and December 15 of each year, beginning December 15, 2018, at a rate of 2.25% per annum; however, the remaining debt discount is being amortized as additional non-cash interest expense using an effective annual interest rate of 5.50% based on the Company's estimated nonconvertible debt borrowing rate.

Interest expense for the fiscal quarter and nine fiscal months ended September 29, 2018 related to the convertible notes due 2025 is reflected on the consolidated condensed statements of operations as follows:

	Contractual coupon interest		Non-cash amortization of debt discount		Non-cash amortization of deferred financing costs		Total interest expense related to the debentures
Fiscal quarter ended September 29, 2018	$	3,375		3,334		454	$	7,163

Nine fiscal months ended September 29, 2018	$	4,088		3,890		605	$	8,583

The convertible notes due 2025 will mature on June 15, 2025, unless earlier repurchased or converted. Prior to December 15, 2024, such conversion is subject to the satisfaction of certain conditions set forth below. The convertible notes due 2025 are not redeemable by the Company before the maturity date.

Prior to December 15, 2024, the holders may only convert their notes under the following circumstances: (1) during any fiscal quarter after the fiscal quarter ending September 29, 2018, if the sale price of Vishay common stock reaches 130% of the conversion price for a specified period (initially $40.94); (2) the trading price of the notes falls below 98% of the product of the sale price of Vishay's common stock and the conversion rate for a specified period; or (3) upon the occurrence of specified corporate transactions.

The convertible notes due 2025 are initially convertible into cash, shares of Vishay common stock, or a combination thereof, at the Company's option, at a conversion rate of 31.7536 shares of common stock per $1,000 principal amount of notes. This initial conversion price represents a premium of 27.5% to the closing price of Vishay's common stock on June 8, 2018, which was $24.70 per share. The conversion rate of the convertible notes is not adjusted for quarterly cash dividends equal to or less than $0.085 per share of common stock. This represents an initial effective conversion price of approximately $31.49 per share. At the direction of its Board of Directors, Vishay intends, upon conversion, to repay the principal amount of the notes in cash and settle any additional amounts in shares. Vishay must provide additional shares upon conversion if there is a "fundamental change" in the business as defined in the indenture governing the notes.

Convertible Senior Debentures

Vishay currently has three issuances of convertible senior debentures outstanding with generally congruent terms.

The Company used substantially all of the net proceeds of the June 2018 issuance of convertible senior notes due 2025 to repurchase $220,000 and $69,060 principal amounts of convertible senior debentures due 2040 and due 2042, respectively. The net carrying value of the debentures repurchased were $89,276 and $29,037, respectively. In accordance with the authoritative accounting guidance for convertible debentures, the aggregate repurchase payment of $584,991 was allocated between the liability ($133,647) and equity (including temporary equity, $451,344) components of the convertible debentures, using the Company's nonconvertible debt borrowing rate at the time of the repurchase. As a result, the Company recognized a loss on extinguishment of convertible debentures of $17,309, including the write-off of a portion of unamortized debt issuance costs.

The quarterly cash dividend program of the Company results in adjustments to the conversion rate and effective conversion price for each issuance of the Company's convertible senior debentures effective as of the ex-dividend date of each cash dividend.

The following table summarizes some key facts and terms regarding the three series of outstanding convertible senior debentures following the adjustment made to the conversion rate of the debentures on the ex-dividend date of the September 27, 2018 dividend payment:

	Due 2040			Due 2041			Due 2042
Issuance date	November 9, 2010			May 13, 2011			May 31, 2012
Maturity date	November 15, 2040			May 15, 2041			June 1, 2042
Principal amount as of September 29, 2018	$	55,000		$	150,000		$	80,940
Cash coupon rate (per annum)		2.25	%		2.25	%		2.25	%
Nonconvertible debt borrowing rate at issuance (per annum)		8.00	%		8.375	%		7.50	%
Conversion rate effective September 13, 2018 (per $1 principal amount)		78.0506			56.9573			91.7689
Effective conversion price effective September 13, 2018 (per share)	$	12.81		$	17.56		$	10.90
130% of the conversion price (per share)	$	16.65		$	22.83		$	14.17
Call date	November 20, 2020			May 20, 2021			June 7, 2022

Prior to three months before the maturity date, the holders may only convert their debentures under the following circumstances: (1) during any fiscal quarter after the first full quarter subsequent to issuance, if the sale price of Vishay common stock reaches 130% of the conversion price for a specified period; (2) the trading price of the debentures falls below 98% of the product of the sale price of Vishay's common stock and the conversion rate for a specified period; (3) Vishay calls any or all of the debentures for redemption, at any time prior to the close of business on the third scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events.

The convertible debentures due 2042 became convertible subsequent to the December 31, 2016 evaluation of the conversion criteria, and have remained convertible for each subsequent quarterly evaluation through the September 29, 2018 evaluation, due to the sale price of Vishay's common stock exceeding 130% of the conversion price for the applicable periods. The convertible debentures due 2040 became convertible subsequent to the September 30, 2017 evaluation of the conversion criteria, and have remained convertible for each subsequent quarterly evaluation through the September 29, 2018 evaluation, due to the sale price of Vishay's common stock exceeding 130% of the conversion price for the applicable periods. The debentures due 2040 and due 2042 will remain convertible until December 31, 2018, at which time the conversion criteria will be reevaluated. At the direction of its Board of Directors, the Company intends, upon future conversion of any of the convertible senior debentures, to repay the principal amounts of the convertible senior debentures in cash and settle any additional amounts in shares of Vishay common stock. The excess of the amount that the Company would pay to the holders of the debentures due 2040 and due 2042 upon conversion over the carrying value of the liability component of the debentures currently convertible has been reclassified as temporary equity on the consolidated condensed financial statements. The Company intends to finance the principal amount of any converted debentures using borrowings under its credit facility. Accordingly, the debt component of the convertible debentures due 2040 and due 2042 continues to be classified as a non-current liability on the consolidated condensed balance sheets.

The carrying values of the liability and equity components of the convertible debentures are reflected in the Company's consolidated condensed balance sheets as follows:

	Principal amount of the debentures		Unamortized discount			Embedded derivative		Carrying value of liability component		Equity component (including temporary equity) - net carrying value
September 29, 2018
Due 2040	$	55,000		(32,561	)		47	$	22,486	$	22,019
Due 2041	$	150,000		(92,549	)		244	$	57,695	$	62,246
Due 2042	$	80,940		(46,735	)		63	$	34,268	$	31,229
Total	$	285,940	$	(171,845	)	$	354	$	114,449	$	115,494

December 31, 2017
Due 2040	$	275,000		(164,794	)		206	$	110,412	$	110,094
Due 2041	$	150,000		(93,573	)		214	$	56,641	$	62,246
Due 2042	$	150,000		(87,600	)		118	$	62,518	$	57,874
Total	$	575,000	$	(345,967	)	$	538	$	229,571	$	230,214

Interest is payable on the debentures semi-annually at the cash coupon rate; however, the remaining debt discount is being amortized as additional non-cash interest expense using an effective annual interest rate equal to the Company's estimated nonconvertible debt borrowing rate at the time of issuance. In addition to ordinary interest, contingent interest will accrue in certain circumstances relating to the trading price of the debentures and under certain other circumstances beginning ten years subsequent to issuance.

Interest expense related to the debentures is reflected on the consolidated condensed statements of operations for the fiscal quarters ended:

	Contractual coupon interest		Non-cash amortization of debt discount		Non-cash amortization of deferred financing costs		Non-cash change in value of derivative liability			Total interest expense related to the debentures
September 29, 2018
Due 2040	$	310		135		4		20		$	469
Due 2041	$	844		349		12		71		$	1,276
Due 2042	$	455		184		7		19		$	665
Total	$	1,609	$	668	$	23	$	110		$	2,410

September 30, 2017
Due 2040	$	1,547		626		22		(53	)	$	2,142
Due 2041	$	844		321		11		(21	)	$	1,155
Due 2042	$	844		312		13		(21	)	$	1,148
Total	$	3,235	$	1,259	$	46	$	(95	)	$	4,445

Interest expense related to the debentures is reflected on the consolidated condensed statements of operations for the nine fiscal months ended:

	Contractual coupon interest		Non-cash amortization of debt discount		Non-cash amortization of deferred financing costs		Non-cash change in value of derivative liability			Total interest expense related to the debentures
September 29, 2018
Due 2040	$	2,991		1,269		42		81		$	4,383
Due 2041	$	2,532		1,024		36		30		$	3,622
Due 2042	$	2,013		783		31		4		$	2,831
Total	$	7,536	$	3,076	$	109	$	115		$	10,836

September 30, 2017
Due 2040	$	4,641		1,841		66		(97	)	$	6,451
Due 2041	$	2,532		943		35		(13	)	$	3,497
Due 2042	$	2,532		919		40		(13	)	$	3,478
Total	$	9,705	$	3,703	$	141	$	(123	)	$	13,426

Accumulated Other Comprehensive Income (Loss)

9 Months Ended

Sep. 29, 2018

Accumulated Other Comprehensive Income (Loss) [Abstract]

Accumulated Other Comprehensive Income (Loss)

Note 7 – Accumulated Other Comprehensive Income (Loss)

The cumulative balance of each component of other comprehensive income (loss) and the income tax effects allocated to each component are as follows:

	Pension and other post-retirement actuarial items			Currency translation adjustment			Unrealized gain (loss) on available-for-sale securities			Total
Balance at January 1, 2018	$	(69,041	)	$	92,954		$	1,801		$	25,714
Cumulative effect of accounting for adoption of ASU 2016-01		-			-			(1,801	)	$	(1,801	)
Other comprehensive income before reclassifications		-			(30,236	)		-		$	(30,236	)
Tax effect		-			-			-		$	-
Other comprehensive income before reclassifications, net of tax		-			(30,236	)		-		$	(30,236	)
Amounts reclassified out of AOCI		6,734			-			-		$	6,734
Tax effect		(1,882	)		-			-		$	(1,882	)
Amounts reclassified out of AOCI, net of tax		4,852			-			-		$	4,852
Net other comprehensive income	$	4,852		$	(30,236	)	$	-		$	(25,384	)
Balance at September 29, 2018	$	(64,189	)	$	62,718		$	-		$	(1,471	)

The Company recognized a cumulative-effect adjustment to retained earnings (accumulated deficit) of $1,801 for the cumulative change in fair value of available-for-sale equity investments previously recognized in other comprehensive income due to the adoption of ASU 2016-01. See Note 1 for further information.

Reclassifications of pension and other post-retirement actuarial items out of AOCI are included in the computation of net periodic benefit cost. See Note 8 for further information.

Pensions and Other Postretirement Benefits

9 Months Ended

Sep. 29, 2018

Pensions and Other Postretirement Benefits [Abstract]

Pensions and Other Postretirement Benefits

Note 8 – Pensions and Other Postretirement Benefits

The Company maintains various retirement benefit plans.

Defined Benefit Pension Plans

The following table shows the components of the net periodic pension cost for the third fiscal quarters of 2018 and 2017 for the Company's defined benefit pension plans:

	Fiscal quarter ended September 29, 2018					Fiscal quarter ended September 30, 2017
	U.S. Plans		Non-U.S. Plans			U.S. Plans		Non-U.S. Plans

Net service cost	$	-	$	900		$	-	$	948
Interest cost		371		1,175			411		1,247
Expected return on plan assets		-		(463	)		-		(519	)
Amortization of prior service cost		36		52			36		19
Amortization of losses		159		1,520			82		1,595
Curtailment and settlement losses		-		441			-		331
Net periodic benefit cost	$	566	$	3,625		$	529	$	3,621

The following table shows the components of the net periodic pension cost for the nine fiscal months ended September 29, 2018 and September 30, 2017 for the Company's defined benefit pension plans:

	Nine fiscal months ended September 29, 2018					Nine fiscal months ended September 30, 2017
	U.S. Plans		Non-U.S. Plans			U.S. Plans		Non-U.S. Plans

Net service cost	$	-	$	2,775		$	-	$	2,776
Interest cost		1,113		3,628			1,232		3,613
Expected return on plan assets		-		(1,430	)		-		(1,543	)
Amortization of prior service cost		108		161			108		55
Amortization of losses		477		4,690			247		4,596
Curtailment and settlement losses		-		1,358			-		983
Net periodic benefit cost	$	1,698	$	11,182		$	1,587	$	10,480

Other Postretirement Benefits

The following table shows the components of the net periodic benefit cost for the third fiscal quarters of 2018 and 2017 for the Company's other postretirement benefit plans:

	Fiscal quarter ended September 29, 2018					Fiscal quarter ended September 30, 2017
	U.S. Plans			Non-U.S. Plans		U.S. Plans			Non-U.S. Plans

Service cost	$	35		$	71	$	33		$	71
Interest cost		69			28		77			26
Amortization of prior service (credit)		(37	)		-		(209	)		-
Amortization of losses (gains)		(10	)		26		(24	)		16
Net periodic benefit cost	$	57		$	125	$	(123	)	$	113

The following table shows the components of the net periodic pension cost for the nine fiscal months ended September 29, 2018 and September 30, 2017 for the Company's other postretirement benefit plans:

	Nine fiscal months ended September 29, 2018					Nine fiscal months ended September 30, 2017
	U.S. Plans			Non-U.S. Plans		U.S. Plans			Non-U.S. Plans

Service cost	$	103		$	219	$	99		$	202
Interest cost		205			86		232			76
Amortization of prior service (credit)		(111	)		-		(627	)		-
Amortization of losses (gains)		(29	)		80		(70	)		45
Net periodic benefit cost	$	168		$	385	$	(366	)	$	323

Stock-Based Compensation

9 Months Ended

Sep. 29, 2018

Stock-Based Compensation [Abstract]

Stock-Based Compensation

Note 9 – Stock-Based Compensation

The Company has various stockholder-approved programs which allow for the grant of stock-based compensation to officers, employees, and non-employee directors of the Company.

The amount of compensation cost related to stock-based payment transactions is measured based on the grant-date fair value of the equity instruments issued. The Company determines compensation cost for restricted stock units ("RSUs") and phantom stock units based on the grant-date fair value of the underlying common stock adjusted for expected dividends paid over the required vesting period for non-participating awards. Compensation cost is recognized over the period that an officer, employee, or non-employee director provides service in exchange for the award.

The following table summarizes stock-based compensation expense recognized:

	Fiscal quarters ended				Nine fiscal months ended
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017

Restricted stock units	$	778	$	676	$	3,825		3,556
Phantom stock units		-		-		214		163
Total	$	778	$	676	$	4,039		3,719

The Company recognizes compensation cost for RSUs that are expected to vest and records cumulative adjustments in the period that the expectation changes.

The following table summarizes unrecognized compensation cost and the weighted average remaining amortization periods at September 29, 2018 (amortization periods in years):

	Unrecognized Compensation Cost		Weighted Average Remaining Amortization Periods

Restricted stock units	$	3,838		1.2
Phantom stock units		-		0.0
Total	$	3,838

The Company currently expects all performance-based RSUs to vest and all of the associated unrecognized compensation cost for performance-based RSUs presented in the table above to be recognized.

2007 Stock Incentive Plan

The Company's 2007 Stock Incentive Program (the "2007 Program"), as amended and restated, permits the grant of up to 6,500,000 shares of restricted stock, unrestricted stock, RSUs, stock options, and phantom stock units, to officers, employees, and non-employee directors of the Company. Such instruments are available for grant until May 20, 2024.

Restricted Stock Units

RSU activity under the 2007 Program as of September 29, 2018 and changes during the nine fiscal months then ended are presented below (number of RSUs in thousands):

	Number of RSUs			Weighted Average Grant-date Fair Value per Unit
Outstanding:
January 1, 2018		986		$	13.34
Granted		252			18.90
Vested*		(334	)		13.67
Cancelled or forfeited		-			-
Outstanding at September 29, 2018		904		$	14.77

Expected to vest at September 29, 2018		904

* The number of RSUs vested includes shares that the Company withheld on behalf of employees to satisfy the statutory tax withholding requirements.

The number of performance-based RSUs that are scheduled to vest increases ratably based on the achievement of defined performance criteria between the established target and maximum levels. RSUs with performance-based vesting criteria are expected to vest as follows (number of RSUs in thousands):

Vesting Date	Expected to Vest		Not Expected to Vest		Total
January 1, 2019		213		-		213
January 1, 2020		167		-		167
January 1, 2021		141		-		141

Phantom Stock Units

The 2007 Program authorizes the grant of phantom stock units to the extent provided for in the Company's employment agreements with certain executives. Each phantom stock unit entitles the recipient to receive a share of common stock at the individual's termination of employment or any other future date specified in the applicable employment agreement. Phantom stock units participate in dividend distribution on the same basis as the Company's common stock and Class B common stock. Dividend equivalents are issued in the form of additional units of phantom stock. The phantom stock units are fully vested at all times.

Phantom stock unit activity under the phantom stock plan as of September 29, 2018 and changes during the nine fiscal months then ended are presented below (number of phantom stock units in thousands):

	Number of units		Grant-date Fair Value per Unit
Outstanding:
January 1, 2018		157
Granted		10	$	21.35
Dividend equivalents issued		2
Outstanding at September 29, 2018		169

Segment Information

9 Months Ended

Sep. 29, 2018

Segment Information [Abstract]

Segment Information

Note 10 – Segment Information

Vishay is a global manufacturer and supplier of electronic components. Vishay operates, and its chief operating decision maker makes strategic and operating decisions with regards to assessing performance and allocating resources based on, five reporting segments: MOSFETs, Diodes, Optoelectronic Components, Resistors & Inductors, and Capacitors. These segments represent groupings of product lines based on their functionality:

●		Metal oxide semiconductor field-effect transistors ("MOSFETs") function as solid-state switches to control power.
●		Diodes route, regulate, and block radio frequency, analog, and power signals; protect systems from surges or electrostatic discharge damage; or provide electromagnetic interference filtering.
●		Optoelectronic components emit light, detect light, or do both.
●		Resistors and inductors both impede electric current. Resistors are basic components used in all forms of electronic circuitry to adjust and regulate levels of voltage and current. Inductors use an internal magnetic field to change alternating current phase and resist alternating current.
●		Capacitors store energy and discharge it when needed.

Vishay's reporting segments generate substantially all of their revenue from product sales to the industrial, automotive, telecommunications, computing, consumer products, power supplies, military and aerospace, and medical end markets. A small portion of revenues is from royalties.

The Company evaluates business segment performance on operating income, exclusive of certain items ("segment operating income"). Only dedicated, direct selling, general, and administrative expenses of the segments are included in the calculation of segment operating income. The Company's calculation of segment operating income excludes such selling, general, and administrative costs as global operations, sales and marketing, information systems, finance and administration groups, as well as restructuring and severance costs, goodwill and long-lived asset impairment charges, and other items. Management believes that evaluating segment performance excluding such items is meaningful because it provides insight with respect to intrinsic operating results of the Company. These items represent reconciling items between segment operating income and consolidated operating income. Business segment assets are the owned or allocated assets used by each business.

The Company also regularly evaluates gross profit by segment to assist in the analysis of consolidated gross profit. The Company considers segment operating income to be the more important metric because it more fully captures the business operations of the segments.

The following tables set forth business segment information:

	MOSFETs		Diodes		Optoelectronic Components		Resistors & Inductors		Capacitors		Total
Fiscal quarter ended September 29, 2018:
Product Sales	$	144,227	$	186,492	$	76,443	$	257,330	$	116,447	$	780,939
Royalty Revenues		33		-		-		-		-	$	33
Total Revenue	$	144,260	$	186,492	$	76,443	$	257,330	$	116,447	$	780,972

Gross Profit	$	38,991	$	54,690	$	27,653	$	88,213	$	26,749	$	236,296

Segment Operating Income	$	29,502	$	49,561	$	23,144	$	80,042	$	21,655	$	203,904

Fiscal quarter ended September 30, 2017:*
Product Sales	$	126,522	$	160,562	$	77,145	$	217,489	$	96,215	$	677,933
Royalty Revenues		-		-		-		8		-	$	8
Total Revenue	$	126,522	$	160,562	$	77,145	$	217,497	$	96,215	$	677,941

Gross Profit	$	32,349	$	43,575	$	29,042	$	65,586	$	19,595	$	190,147

Segment Operating Income	$	23,434	$	38,694	$	25,214	$	58,328	$	14,705	$	160,375

Nine fiscal months ended September 29, 2018:
Product Sales	$	408,280	$	535,975	$	224,110	$	755,262	$	335,064	$	2,258,691
Royalty Revenues		45		-		-		61		-	$	106
Total Revenue	$	408,325	$	535,975	$	224,110	$	755,323	$	335,064	$	2,258,797

Gross Profit	$	109,440	$	150,298	$	81,290	$	251,712	$	76,094	$	668,834

Segment Operating Income	$	80,577	$	134,592	$	68,103	$	226,292	$	60,258	$	569,822

Nine fiscal months ended September 30, 2017:*
Product Sales	$	345,399	$	460,492	$	215,040	$	626,684	$	278,241	$	1,925,856
Royalty Revenues		-		-		-		50		-	$	50
Total Revenue	$	345,399	$	460,492	$	215,040	$	626,734	$	278,241	$	1,925,906

Gross Profit	$	78,423	$	123,499	$	77,091	$	188,936	$	57,784	$	525,733

Segment Operating Income	$	51,917	$	109,014	$	64,007	$	167,035	$	43,041	$	435,014

*Recast for the retrospective adoption of ASUs 2014-09 and 2017-07. See Note 1.

	Fiscal quarters ended						Nine fiscal months ended
	September 29, 2018			September 30, 2017***			September 29, 2018			September 30, 2017***
Reconciliation:
Segment Operating Income	$	203,904		$	160,375		$	569,822		$	435,014
Restructuring and Severance Costs		-			(3,244	)		-			(5,194	)
Unallocated Selling, General, and Administrative Expenses		(65,806	)		(61,715	)		(204,369	)		(181,821	)
Consolidated Operating Income	$	138,098		$	95,416		$	365,453		$	247,999
Unallocated Other Income (Expense)		(11,290	)		(9,228	)		(49,067	)		(35,660	)
Consolidated Income Before Taxes	$	126,808		$	86,188		$	316,386		$	212,339

***Recast for the adoption of ASU 2017-07. See Note 1.

The Company has a broad line of products that it sells to OEMs, EMS companies, and independent distributors. The distribution of sales by customer type is shown below:

	Fiscal quarters ended				Nine fiscal months ended				Years Ended December 31,
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017		2017		2016
Distributors	$	452,051	$	383,727	$	1,302,127	$	1,102,232	$	1,484,276	$	1,280,060
OEMs		276,299		247,551		803,128		685,565		931,291		861,322
EMS companies		52,622		46,663		153,542		138,109		183,801		175,946
Total Revenue	$	780,972	$	677,941	$	2,258,797	$	1,925,906	$	2,599,368	$	2,317,328

Net revenues were attributable to customers in the following regions:

	Fiscal quarters ended				Nine fiscal months ended				Years Ended December 31,
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017		2017		2016
Asia	$	315,701	$	282,416	$	904,047	$	811,987	$	1,091,107	$	948,195
Europe		269,518		237,874		809,501		665,049		902,357		810,543
Americas		195,753		157,651		545,249		448,870		605,904		558,590
Total Revenue	$	780,972	$	677,941	$	2,258,797	$	1,925,906	$	2,599,368	$	2,317,328

The Company generates substantially all of its revenue from product sales to end customers in the industrial, automotive, telecommunications, computing, consumer products, power supplies, military and aerospace, and medical end markets. Sales by end market are presented below:

	Fiscal quarters ended				Nine fiscal months ended				Years Ended December 31,
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017		2017		2016
Industrial	$	283,134	$	242,038	$	858,963	$	691,678	$	934,631	$	796,031
Automotive		224,041		185,781		642,293		537,008		727,220		640,767
Telecommunications		51,935		50,710		144,326		143,828		190,682		193,456
Computing		62,774		55,380		163,862		143,948		198,850		172,481
Consumer Products		48,583		40,155		126,781		108,711		145,243		150,741
Power Supplies		34,899		44,327		110,468		120,223		160,038		132,555
Military and Aerospace		41,881		33,029		117,355		98,753		132,898		128,523
Medical		33,725		26,521		94,749		81,757		109,806		102,774
Total revenue	$	780,972	$	677,941		2,258,797		1,925,906	$	2,599,368	$	2,317,328

Earnings Per Share

9 Months Ended

Sep. 29, 2018

Earnings Per Share [Abstract]

Earnings Per Share

Note 11 – Earnings Per Share

The following table sets forth the computation of basic and diluted earnings (loss) per share attributable to Vishay stockholders (shares in thousands):

	Fiscal quarters ended				Nine fiscal months ended
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017

Numerator:
Net earnings attributable to Vishay stockholders	$	77,876	$	64,404	$	243,339	$	157,313

Denominator:
Denominator for basic earnings per share:
Weighted average shares		144,215		145,572		144,197		145,973
Outstanding phantom stock units		168		156		167		155
Adjusted weighted average shares		144,383		145,728		144,364		146,128

Effect of dilutive securities:
Convertible and exchangeable debt instruments		8,062		10,480		11,827		9,160
Restricted stock units		501		493		511		338
Dilutive potential common shares		8,563		10,973		12,338		9,498

Denominator for diluted earnings per share:
Adjusted weighted average shares - diluted		152,946		156,701		156,702		155,626

Basic earnings per share attributable to Vishay stockholders	$	0.54	$	0.44	$	1.69	$	1.08

Diluted earnings per share attributable to Vishay stockholders	$	0.51	$	0.41	$	1.55	$	1.01

Diluted earnings (loss) per share for the periods presented do not reflect the following weighted average potential common shares that would have an antidilutive effect or have unsatisfied performance conditions (in thousands):

	Fiscal quarters ended				Nine fiscal months ended
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017
Convertible debt:
Convertible Senior Debentures, due 2041		-		8,401		-		8,371
Convertible Senior Notes, due 2025		19,052		-		7,607		-
Weighted average other		307		379		307		514

The Company's convertible debt instruments are only convertible for specified periods upon the occurrence of certain events. The convertible debentures due 2042 became convertible subsequent to the December 31, 2016 evaluation of the conversion criteria, and have remained convertible for each subsequent quarterly evaluation through the September 29, 2018 evaluation. The convertible debentures due 2040 became convertible subsequent to the September 30, 2017 evaluation of the conversion criteria, and have remained convertible for each subsequent quarterly evaluation through the September 29, 2018 evaluation. In periods that the debentures are not convertible, the certain conditions which could trigger conversion of the remaining debentures have been deemed to be non-substantive, and accordingly, the Company assumes the conversion of these instruments in its diluted earnings per share computation during periods in which they are dilutive.

At the direction of its Board of Directors, the Company intends, upon conversion, to repay the principal amounts of the convertible senior debentures, due 2040, due 2041, and due 2042, and the convertible senior notes, due 2025, in cash and settle any additional amounts in shares of Vishay common stock. Accordingly, the convertible instruments are included in the diluted earnings per share computation using the "treasury stock method" (similar to options and warrants) rather than the "if converted method" otherwise required for convertible debt. Under the "treasury stock method," Vishay calculates the number of shares issuable under the terms of the debentures based on the average market price of Vishay common stock during the period, and that number is included in the total diluted shares figure for the period. If the average market price is less than $12.81, no shares are included in the diluted earnings per share computation for the convertible senior debentures due 2040, if the average market price is less than $17.56, no shares are included in the diluted earnings per share computation for the convertible senior debentures due 2041, if the average market price is less than $10.90, no shares are included in the diluted earnings per share computation for the convertible senior debentures due 2042, and if the average market price is less than $31.49, no shares are included in the diluted earnings per share computation for the convertible senior notes due 2025.

Fair Value Measurements

9 Months Ended

Sep. 29, 2018

Fair Value Measurements [Abstract]

Fair Value Measurements

Note 12 – Fair Value Measurements

The fair value measurement accounting guidance establishes a valuation hierarchy of the inputs used to measure fair value. This hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The following is a brief description of those three levels:

Level 1: Observable inputs such as quoted prices (unadjusted) in active markets for identical assets or liabilities.

Level 2: Inputs other than quoted prices that are observable for the asset or liability, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active.

Level 3: Unobservable inputs that reflect the Company's own assumptions.

An asset or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. There have been no changes in the classification of any financial instruments within the fair value hierarchy in the periods presented.

The following table provides the financial assets and liabilities carried at fair value measured on a recurring basis:

	Total Fair Value			Level 1		Level 2		Level 3
September 29, 2018
Assets:
Assets held in rabbi trusts	$	43,701		$	26,363	$	17,338	$	-
Available for sale securities	$	4,429			4,429		-		-
	$	48,130		$	30,792	$	17,338	$	-
Liabilities:
Embedded derivative - convertible debentures due 2040	$	(47	)	$	-	$	-	$	(47	)
Embedded derivative - convertible debentures due 2041	$	(244	)		-		-		(244	)
Embedded derivative - convertible debentures due 2042	$	(63	)		-		-		(63	)
	$	(354	)	$	-	$	-	$	(354	)
December 31, 2017
Assets:
Assets held in rabbi trusts	$	45,252		$	28,589		16,663	$	-
Available for sale securities	$	4,621			4,621		-		-
	$	49,873		$	33,210	$	16,663	$	-
Liabilities:
Embedded derivative - convertible debentures due 2040	$	(206	)	$	-	$	-	$	(206	)
Embedded derivative - convertible debentures due 2041	$	(214	)		-		-		(214	)
Embedded derivative - convertible debentures due 2042	$	(118	)		-		-		(118	)
	$	(538	)	$	-	$	-	$	(538	)

As described in Note 6, the Company allocated the aggregate repurchase payment of convertible senior debentures between the associated liability and equity components of the repurchased convertible senior debentures based on a nonrecurring fair value measurement of the convertible senior debentures due 2040 and due 2042 immediately prior to the repurchase. The nonrecurring fair value measurement is considered a Level 3 measurement. See Note 6 for further information on the measurement and input.

The Company maintains non-qualified trusts, referred to as "rabbi" trusts, to fund payments under deferred compensation and non-qualified pension plans. Rabbi trust assets consist primarily of marketable securities, classified as available-for-sale and company-owned life insurance assets. The marketable securities held in the rabbi trusts are valued using quoted market prices on the last business day of the period. The company-owned life insurance assets are valued in consultation with the Company's insurance brokers using the value of underlying assets of the insurance contracts. The fair value measurement of the marketable securities held in the rabbi trust is considered a Level 1 measurement and the measurement of the company-owned life insurance assets is considered a Level 2 measurement within the fair value hierarchy.

The Company holds investments in equity securities that are intended to fund a portion of its pension and other postretirement benefit obligations outside of the United States. The investments are valued based on quoted market prices on the last business day of the period. The fair value measurement of the investments is considered a Level 1 measurement within the fair value hierarchy.

The convertible senior debentures, due 2040, due 2041, and due 2042, issued by the Company on November 9, 2010, May 13, 2011, and May 31, 2012, respectively, contain embedded derivative features that GAAP requires to be bifurcated and remeasured each reporting period. Each quarter, the change in the fair value of the embedded derivative features, if any, is recorded in the consolidated condensed statements of operations. The Company uses a derivative valuation model to derive the value of the embedded derivative features. Key inputs into this valuation model are the Company's current stock price, risk-free interest rates, the stock dividend yield, the stock volatility, and the debentures' credit spread over LIBOR. The first three aforementioned inputs are based on observable market data and are considered Level 2 inputs while the last two aforementioned inputs are unobservable and thus require management's judgment and are considered Level 3 inputs. The fair value measurement is considered a Level 3 measurement within the fair value hierarchy.

The Company has entered into forward contracts with highly-rated financial institutions to mitigate the foreign currency risk associated with intercompany loans denominated in a currency other than the legal entity's functional currency. The notional amount of the forward contracts was $100,000 as of December 31, 2017. There were no such contracts outstanding as of September 29, 2018. The forward contracts were short-term in nature and were renewed at the Company's discretion until the intercompany loans were repaid. We did not designate the forward contracts as hedges for accounting purposes, and as such the change in the fair value of the contracts was recognized in the consolidated condensed statements of operations as a component of other income (expense). The Company estimated the fair value of the forward contracts based on applicable and commonly used pricing models using current market information and is considered a Level 2 measurement within the fair value hierarchy. The value of the forward contracts was immaterial as of December 31, 2017. The Company does not utilize derivatives or other financial instruments for trading or other speculative purposes.

The fair value of the long-term debt, excluding the derivative liabilities and deferred financing costs, at September 29, 2018 and December 31, 2017 is approximately $989,400 and $1,071,200, respectively, compared to its carrying value, excluding the derivative liabilities and deferred financing costs, of $605,948 and $379,033, respectively. The Company estimates the fair value of its long-term debt using a combination of quoted market prices for similar financing arrangements and expected future payments discounted at risk-adjusted rates, which are considered Level 2 inputs.

At September 29, 2018 and December 31, 2017, the Company's short-term investments were comprised of time deposits with financial institutions that have maturities that exceed 90 days from the date of acquisition; however they all mature within one year from the respective balance sheet dates. The Company's short-term investments are accounted for as held-to-maturity debt instruments, at amortized cost, which approximates their fair value. The investments are funded with excess cash not expected to be needed for operations prior to maturity; therefore, the Company believes it has the intent and ability to hold the short-term investments until maturity. At each reporting date, the Company performs an evaluation to determine if any unrealized losses are other-than-temporary. No other-than-temporary impairments have been recognized on these securities, and there are no unrecognized holding gains or losses for these securities during the periods presented. There have been no transfers to or from the held-to-maturity classification. All decreases in the account balance are due to returns of principal at the securities' maturity dates. Interest on the securities is recognized as interest income when earned.

At September 29, 2018 and December 31, 2017, the Company's cash and cash equivalents were comprised of demand deposits, time deposits with maturities of three months or less when purchased, and money market funds. The Company estimates the fair value of its cash, cash equivalents, and short-term investments using level 2 inputs. Based on the current interest rates for similar investments with comparable credit risk and time to maturity, the fair value of the Company's cash, cash equivalents, and held-to-maturity short-term investments approximate the carrying amounts reported in the consolidated condensed balance sheets.

The Company's financial instruments also include accounts receivable, short-term notes payable, and accounts payable. The carrying amounts for these financial instruments reported in the consolidated condensed balance sheets approximate their fair values.

- 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

Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation (Policies)	Sep. 29, 2018
New Accounting Pronouncements [Abstract]
Fiscal Period, Policy	The Company reports interim financial information for 13-week periods beginning on a Sunday and ending on a Saturday, except for the first fiscal quarter, which always begins on January 1, and the fourth fiscal quarter, which always ends on December 31. The four fiscal quarters in 2018 end on March 31, 2018, June 30, 2018, September 29, 2018, and December 31, 2018, respectively. The four fiscal quarters in 2017 ended on April 1, 2017, July 1, 2017, September 30, 2017, and December 31, 2017, respectively.
Description of New Accounting Pronouncements Not yet Adopted [Text Block]	Recently Issued Accounting Guidance In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The ASU is the result of a project between the FASB and the International Accounting Standards Board to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Upon adoption of the ASU, the Company will recognize lease assets and liabilities for its operating leases which are not currently reported on its consolidated balance sheets. The ASU is effective for the Company for interim and annual periods beginning on or after January 1, 2019, with the ability to early adopt. The Company is currently evaluating the effect of the ASU on its lease contracts. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU replaces the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The ASU is effective for the Company for interim and annual periods beginning on or after January 1, 2020, with the ability to early adopt for interim and annual periods beginning on or after January 1, 2019. The Company is currently evaluating the effect of the ASU on its financial assets measured at amortized cost.
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Recently Adopted Accounting Guidance In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The ASU is the result of a convergence project between the FASB and the International Accounting Standards Board to clarify the principles for recognizing revenue and to develop a common revenue standard for GAAP and International Financial Reporting Standards. The ASU removes inconsistencies and weaknesses in revenue requirements; provides a more robust framework for addressing revenue issues; improves comparability of revenue recognition practices across entities, industries, jurisdictions, and capital markets; provides more useful information to users of financial statements through expanded disclosure requirements; and simplifies the preparation of financial statements by reducing the number of requirements to which an entity must refer. The Company retrospectively adopted the ASU on January 1, 2018. The adoption of the ASU did not have a material impact on the Company's results of operations. See Note 2 and "Changes in Accounting Policies" below. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The ASU enhances the reporting model for financial instruments by addressing certain aspects, including requiring equity investments to be measured at fair value with changes in fair value recognized in net income; simplifying the impairment assessment of equity investments without readily determinable fair values; eliminating the requirement to disclose the method and significant assumptions used to estimate the disclosed fair value of financial instruments measured at amortized cost; and requiring the use of the exit price notion for fair value measurements of financial instruments for disclosure purposes. The Company adopted the ASU on January 1, 2018. The Company recognized a cumulative-effect adjustment to January 1, 2018 retained earnings (accumulated deficit) of $1,801 for the cumulative change in fair value of available-for-sale equity investments previously recognized in other comprehensive income. The adoption of the ASU did not have a material impact on the Company's results of operations. In March 2017, the FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The ASU amends the income statement presentation requirements of net periodic benefit cost of defined benefit pension and other postretirement plans. The Company retrospectively adopted the ASU on January 1, 2018. The adoption of the ASU did not have a material impact on the Company's results of operations. See "Changes in Accounting Policies" below.

Income Taxes (Policies)	9 Months Ended
Income Taxes (Policies)	Sep. 29, 2018
Income Taxes [Abstract]
Effective Income tax Rate Description	The provision for income taxes consists of provisions for federal, state, and foreign income taxes. The effective tax rates for the periods ended September 29, 2018 and September 30, 2017 reflect the Company's expected tax rate on reported income from continuing operations before income tax and tax adjustments. The Company operates in a global environment with significant operations in various jurisdictions outside the United States. Accordingly, the consolidated income tax rate is a composite rate reflecting the Company's earnings and the applicable tax rates in the various jurisdictions where the Company operates.

Stock-Based Compensation (Policies)	9 Months Ended
Stock-Based Compensation (Policies)	Sep. 29, 2018
Stock-Based Compensation [Abstract]
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	The amount of compensation cost related to stock-based payment transactions is measured based on the grant-date fair value of the equity instruments issued. The Company determines compensation cost for restricted stock units ("RSUs") and phantom stock units based on the grant-date fair value of the underlying common stock adjusted for expected dividends paid over the required vesting period for non-participating awards. Compensation cost is recognized over the period that an officer, employee, or non-employee director provides service in exchange for the award.

Segment Information (Policies)

9 Months Ended

Sep. 29, 2018

Segment Information [Abstract]

Segment Reporting, Policy [Policy Text Block]

●		Metal oxide semiconductor field-effect transistors ("MOSFETs") function as solid-state switches to control power.
●		Diodes route, regulate, and block radio frequency, analog, and power signals; protect systems from surges or electrostatic discharge damage; or provide electromagnetic interference filtering.
●		Optoelectronic components emit light, detect light, or do both.
●		Resistors and inductors both impede electric current. Resistors are basic components used in all forms of electronic circuitry to adjust and regulate levels of voltage and current. Inductors use an internal magnetic field to change alternating current phase and resist alternating current.
●		Capacitors store energy and discharge it when needed.

Earnings Per Share (Policies)	9 Months Ended
Earnings Per Share (Policies)	Sep. 29, 2018
Earnings Per Share [Abstract]
Discussion on convertible debt included in computation of earnings per share diluted	The Company's convertible debt instruments are only convertible for specified periods upon the occurrence of certain events. The convertible debentures due 2042 became convertible subsequent to the December 31, 2016 evaluation of the conversion criteria, and have remained convertible for each subsequent quarterly evaluation through the September 29, 2018 evaluation. The convertible debentures due 2040 became convertible subsequent to the September 30, 2017 evaluation of the conversion criteria, and have remained convertible for each subsequent quarterly evaluation through the September 29, 2018 evaluation. In periods that the debentures are not convertible, the certain conditions which could trigger conversion of the remaining debentures have been deemed to be non-substantive, and accordingly, the Company assumes the conversion of these instruments in its diluted earnings per share computation during periods in which they are dilutive. At the direction of its Board of Directors, the Company intends, upon conversion, to repay the principal amounts of the convertible senior debentures, due 2040, due 2041, and due 2042, and the convertible senior notes, due 2025, in cash and settle any additional amounts in shares of Vishay common stock. Accordingly, the convertible instruments are included in the diluted earnings per share computation using the "treasury stock method" (similar to options and warrants) rather than the "if converted method" otherwise required for convertible debt. Under the "treasury stock method," Vishay calculates the number of shares issuable under the terms of the debentures based on the average market price of Vishay common stock during the period, and that number is included in the total diluted shares figure for the period. If the average market price is less than $12.81, no shares are included in the diluted earnings per share computation for the convertible senior debentures due 2040, if the average market price is less than $17.56, no shares are included in the diluted earnings per share computation for the convertible senior debentures due 2041, if the average market price is less than $10.90, no shares are included in the diluted earnings per share computation for the convertible senior debentures due 2042, and if the average market price is less than $31.49, no shares are included in the diluted earnings per share computation for the convertible senior notes due 2025.

Fair Value Measurements (Policies)	9 Months Ended
Fair Value Measurements (Policies)	Sep. 29, 2018
Fair Value Measurements [Abstract]
Fair Value of Financial Instruments, Policy	The fair value measurement accounting guidance establishes a valuation hierarchy of the inputs used to measure fair value. This hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The following is a brief description of those three levels: Level 1: Observable inputs such as quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2: Inputs other than quoted prices that are observable for the asset or liability, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active. Level 3: Unobservable inputs that reflect the Company's own assumptions. An asset or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. There have been no changes in the classification of any financial instruments within the fair value hierarchy in the periods presented.

Basis of Presentation (Tables)

9 Months Ended

Sep. 29, 2018

New Accounting Pronouncements [Abstract]

Schedule of Retrospective Adoption of New Accounting Pronouncements [Table Text Block]

The retrospective adoption of ASUs 2014-09 and 2017-07 did not impact net earnings (loss) attributed to Vishay stockholders. See the combined impact of the retrospective adoption in the tables below:

Fiscal quarters ended
	April 1, 2017									July 1, 2017									September 30, 2017									December 31, 2017
	As Reported			Adjustments			Recast			As Reported			Adjustments			Recast			As Reported			Adjustments			Recast			As Reported			Adjustments			Recast

Net revenues	$	606,258		$	(1,457	)	$	604,801		$	644,892		$	(1,728	)	$	643,164		$	677,883		$	58		$	677,941		$	674,489		$	(1,027	)	$	673,462
Costs of products sold		445,383			(2,331	)		443,052			471,929			(2,602	)		469,327			488,610			(816	)		487,794			497,988			(1,902	)		496,086
Gross profit		160,875			874			161,749			172,963			874			173,837			189,273			874			190,147			176,501			875			177,376
Operating income		64,688			2,890			67,578			82,036			2,969			85,005			92,328			3,088			95,416			72,536			3,470			76,006
Total other income (expense)		(14,246	)		(2,890	)		(17,136	)		(6,327	)		(2,969	)		(9,296	)		(6,140	)		(3,088	)		(9,228	)		(5,511	)		(3,470	)		(8,981	)
Income before taxes		50,442			-			50,442			75,709			-			75,709			86,188			-			86,188			67,025			-			67,025
Income tax expense		13,493			-			13,493			19,300			-			19,300			21,605			-			21,605			244,526			-			244,526
Net earnings (loss)		36,949			-			36,949			56,409			-			56,409			64,583			-			64,583			(177,501	)		-			(177,501	)
Less: net earnings attributable to noncontrolling interests		230			-			230			219			-			219			179			-			179			156			-			156
Net earnings (loss) attributable to Vishay stockholders	$	36,719		$	-		$	36,719		$	56,190		$	-		$	56,190		$	64,404		$	-		$	64,404		$	(177,657	)	$	-		$	(177,657	)

	Years ended
	December 31, 2016									December 31, 2017
	As Reported			Adjustments			Recast			As Reported			Adjustments			Recast

Net revenues	$	2,323,431		$	(6,103	)	$	2,317,328		$	2,603,522		$	(4,154	)	$	2,599,368
Costs of products sold		1,753,648			(10,142	)		1,743,506			1,903,910			(7,651	)		1,896,259
Gross profit		569,783			4,039			573,822			699,612			3,497			703,109
Operating income		101,717			95,341			197,058			311,588			12,417			324,005
Total other income (expense)		(7,501	)		(95,341	)		(102,842	)		(32,224	)		(12,417	)		(44,641	)
Income before taxes		94,216			-			94,216			279,364			-			279,364
Income tax expense		44,843			-			44,843			298,924			-			298,924
Net earnings (loss)		49,373			-			49,373			(19,560	)		-			(19,560	)
Less: net earnings attributable to noncontrolling interests		581			-			581			784			-			784
Net earnings (loss) attributable to Vishay stockholders	$	48,792		$	-		$	48,792		$	(20,344	)	$	-		$	(20,344	)

Revenue Recognition Policies (Tables)

9 Months Ended

Sep. 29, 2018

Revenue Recognition Policies

Schedule of Loss Contingencies by Contingency [Table Text Block]

Distributor sales accrual activity is shown below:

	Fiscal quarters ended						Nine fiscal months ended						Years Ended December 31,
	September 29, 2018			September 30, 2017			September 29, 2018			September 30, 2017			2017			2016
Beginning balance	$	38,032		$	35,733		$	36,680		$	34,479		$	34,479		$	32,487
Sales allowances		27,986			22,421			77,539			67,191			89,009			86,896
Credits issued		(29,293	)		(28,116	)		(77,091	)		(71,638	)		(87,403	)		(85,341	)
Foreign currency		103			384			(300	)		390			595			437
Ending balance	$	36,828		$	30,422		$	36,828		$	30,422		$	36,680		$	34,479

- Definition

Tabular disclosure of the loss contingencies that were reported in the period or disclosed as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14472-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12021-110248

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14453-108349

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82913245&loc=d3e12053-110248

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14394-108349

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14557-108349

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14615-108349

+ Details

Restructuring and Related Activities (Tables)

9 Months Ended

Sep. 29, 2018

Restructuring and Related Activities [Abstract]

Restructuring and Related Expenses

The following table summarizes restructuring and related expenses which were recognized and reported on a separate line in the accompanying consolidated condensed statements of operations:

	Fiscal quarter ended		Nine fiscal months ended
	September 30, 2017		September 30, 2017
MOSFETs Enhanced Competitiveness Program	$	2,463	$	2,911
Global Cost Reduction Programs		781		2,283
Total	$	3,244	$	5,194

MOSFETs Enhanced Competitiveness Program [Member]

Restructuring Cost and Reserve [Line Items]

Schedule of Restructuring Reserve by Type of Cost [Table Text Block]

The following table summarizes the activity to date related to this program:

Expense recorded in 2013	$	2,328
Cash paid		(267	)
Balance at December 31, 2013	$	2,061
Expense recorded in 2014		6,025
Cash paid		(856	)
Balance at December 31, 2014	$	7,230
Expense recorded in 2015		5,367
Cash paid		(426	)
Foreign currency translation		1
Balance at December 31, 2015	$	12,172
Expense recorded in 2016		9,744
Cash paid		(15,686	)
Foreign currency translation		2
Balance at December 31, 2016	$	6,232
Expense recorded in 2017		3,204
Cash paid		(7,173	)
Balance at December 31, 2017	$	2,263
Cash paid		(1,051	)
Balance at September 29, 2018	$	1,212

Global Cost Reduction Program [Member]

Restructuring Cost and Reserve [Line Items]

Schedule of Restructuring Reserve by Type of Cost [Table Text Block]

The following table summarizes the activity to date related to this program:

Expense recorded in 2015	$	13,753
Cash paid		(986	)
Foreign currency translation		(150	)
Balance at December 31, 2015	$	12,617
Expense recorded in 2016		9,918
Cash paid		(16,237	)
Foreign currency translation		(34	)
Balance at December 31, 2016	$	6,264
Expense recorded in 2017		8,069
Cash paid		(7,168	)
Foreign currency translation		500
Balance at December 31, 2017	$	7,665
Cash paid		(2,881	)
Foreign currency translation		(87	)
Balance at September 29, 2018	$	4,697

Restructuring expenses by segment [Table Text Block]

The following table summarizes the expense recognized by segment related to this program:

	Fiscal quarter ended			Nine fiscal months ended
	September 30, 2017			September 30, 2017
Diodes	$	(13	)	$	-
Optoelectronic Components		-			242
Resistors & Inductors		468			1,403
Capacitors		88			334
Unallocated Selling, General, and Administrative Expenses		238			304
Total	$	781		$	2,283

Long-Term Debt (Tables)

9 Months Ended

Sep. 29, 2018

Debt Instrument [Line Items]

Schedule of long-term debt instruments

Long-term debt consists of the following:

	September 29, 2018			December 31, 2017

Credit facility	$	-		$	150,000
Convertible senior debentures, due 2040		22,486			110,412
Convertible senior debentures, due 2041		57,695			56,641
Convertible senior debentures, due 2042		34,268			62,518
Convertible notes, due 2025		491,853			-
Deferred financing costs		(17,716	)		(9,101	)
		588,586			370,470
Less current portion		-			-
	$	588,586		$	370,470

Convertible Senior Notes, Due 2025 [Member]

Debt Instrument [Line Items]

Convertible debentures, interest expense

	Contractual coupon interest		Non-cash amortization of debt discount		Non-cash amortization of deferred financing costs		Total interest expense related to the debentures
Fiscal quarter ended September 29, 2018	$	3,375		3,334		454	$	7,163

Nine fiscal months ended September 29, 2018	$	4,088		3,890		605	$	8,583

Liability and equity of component of convertible senior debentures

The carrying values of the liability and equity components of the convertible notes are reflected in the Company's consolidated balance sheets as follows:

	Principal amount of the notes		Unamortized discount			Carrying value of liability component		Equity component - net carrying value
September 29, 2018
Due 2025	$	600,000		(108,147	)	$	491,853	$	85,262

Convertible senior debentures [Member]

Debt Instrument [Line Items]

Convertible debentures, interest expense

Interest expense related to the debentures is reflected on the consolidated condensed statements of operations for the fiscal quarters ended:

	Contractual coupon interest		Non-cash amortization of debt discount		Non-cash amortization of deferred financing costs		Non-cash change in value of derivative liability			Total interest expense related to the debentures
September 29, 2018
Due 2040	$	310		135		4		20		$	469
Due 2041	$	844		349		12		71		$	1,276
Due 2042	$	455		184		7		19		$	665
Total	$	1,609	$	668	$	23	$	110		$	2,410

September 30, 2017
Due 2040	$	1,547		626		22		(53	)	$	2,142
Due 2041	$	844		321		11		(21	)	$	1,155
Due 2042	$	844		312		13		(21	)	$	1,148
Total	$	3,235	$	1,259	$	46	$	(95	)	$	4,445

Interest expense related to the debentures is reflected on the consolidated condensed statements of operations for the nine fiscal months ended:

	Contractual coupon interest		Non-cash amortization of debt discount		Non-cash amortization of deferred financing costs		Non-cash change in value of derivative liability			Total interest expense related to the debentures
September 29, 2018
Due 2040	$	2,991		1,269		42		81		$	4,383
Due 2041	$	2,532		1,024		36		30		$	3,622
Due 2042	$	2,013		783		31		4		$	2,831
Total	$	7,536	$	3,076	$	109	$	115		$	10,836

September 30, 2017
Due 2040	$	4,641		1,841		66		(97	)	$	6,451
Due 2041	$	2,532		943		35		(13	)	$	3,497
Due 2042	$	2,532		919		40		(13	)	$	3,478
Total	$	9,705	$	3,703	$	141	$	(123	)	$	13,426

Liability and equity of component of convertible senior debentures

The carrying values of the liability and equity components of the convertible debentures are reflected in the Company's consolidated condensed balance sheets as follows:

	Principal amount of the debentures		Unamortized discount			Embedded derivative		Carrying value of liability component		Equity component (including temporary equity) - net carrying value
September 29, 2018
Due 2040	$	55,000		(32,561	)		47	$	22,486	$	22,019
Due 2041	$	150,000		(92,549	)		244	$	57,695	$	62,246
Due 2042	$	80,940		(46,735	)		63	$	34,268	$	31,229
Total	$	285,940	$	(171,845	)	$	354	$	114,449	$	115,494

December 31, 2017
Due 2040	$	275,000		(164,794	)		206	$	110,412	$	110,094
Due 2041	$	150,000		(93,573	)		214	$	56,641	$	62,246
Due 2042	$	150,000		(87,600	)		118	$	62,518	$	57,874
Total	$	575,000	$	(345,967	)	$	538	$	229,571	$	230,214

Key terms of the convertible debentures

	Due 2040			Due 2041			Due 2042
Issuance date	November 9, 2010			May 13, 2011			May 31, 2012
Maturity date	November 15, 2040			May 15, 2041			June 1, 2042
Principal amount as of September 29, 2018	$	55,000		$	150,000		$	80,940
Cash coupon rate (per annum)		2.25	%		2.25	%		2.25	%
Nonconvertible debt borrowing rate at issuance (per annum)		8.00	%		8.375	%		7.50	%
Conversion rate effective September 13, 2018 (per $1 principal amount)		78.0506			56.9573			91.7689
Effective conversion price effective September 13, 2018 (per share)	$	12.81		$	17.56		$	10.90
130% of the conversion price (per share)	$	16.65		$	22.83		$	14.17
Call date	November 20, 2020			May 20, 2021			June 7, 2022

Accumulated Other Comprehensive Income (Loss) (Tables)

9 Months Ended

Sep. 29, 2018

Accumulated Other Comprehensive Income (Loss) [Abstract]

Summary of components of other comprehensive income

The cumulative balance of each component of other comprehensive income (loss) and the income tax effects allocated to each component are as follows:

	Pension and other post-retirement actuarial items			Currency translation adjustment			Unrealized gain (loss) on available-for-sale securities			Total
Balance at January 1, 2018	$	(69,041	)	$	92,954		$	1,801		$	25,714
Cumulative effect of accounting for adoption of ASU 2016-01		-			-			(1,801	)	$	(1,801	)
Other comprehensive income before reclassifications		-			(30,236	)		-		$	(30,236	)
Tax effect		-			-			-		$	-
Other comprehensive income before reclassifications, net of tax		-			(30,236	)		-		$	(30,236	)
Amounts reclassified out of AOCI		6,734			-			-		$	6,734
Tax effect		(1,882	)		-			-		$	(1,882	)
Amounts reclassified out of AOCI, net of tax		4,852			-			-		$	4,852
Net other comprehensive income	$	4,852		$	(30,236	)	$	-		$	(25,384	)
Balance at September 29, 2018	$	(64,189	)	$	62,718		$	-		$	(1,471	)

Pensions and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 29, 2018

Defined Benefit Pension Plan [Member]

Defined Benefit Plan Disclosure [Line Items]

Net periodic benefit cost for pension and other postretirement benefit plans

The following table shows the components of the net periodic pension cost for the third fiscal quarters of 2018 and 2017 for the Company's defined benefit pension plans:

	Fiscal quarter ended September 29, 2018					Fiscal quarter ended September 30, 2017
	U.S. Plans		Non-U.S. Plans			U.S. Plans		Non-U.S. Plans

Net service cost	$	-	$	900		$	-	$	948
Interest cost		371		1,175			411		1,247
Expected return on plan assets		-		(463	)		-		(519	)
Amortization of prior service cost		36		52			36		19
Amortization of losses		159		1,520			82		1,595
Curtailment and settlement losses		-		441			-		331
Net periodic benefit cost	$	566	$	3,625		$	529	$	3,621

The following table shows the components of the net periodic pension cost for the nine fiscal months ended September 29, 2018 and September 30, 2017 for the Company's defined benefit pension plans:

	Nine fiscal months ended September 29, 2018					Nine fiscal months ended September 30, 2017
	U.S. Plans		Non-U.S. Plans			U.S. Plans		Non-U.S. Plans

Net service cost	$	-	$	2,775		$	-	$	2,776
Interest cost		1,113		3,628			1,232		3,613
Expected return on plan assets		-		(1,430	)		-		(1,543	)
Amortization of prior service cost		108		161			108		55
Amortization of losses		477		4,690			247		4,596
Curtailment and settlement losses		-		1,358			-		983
Net periodic benefit cost	$	1,698	$	11,182		$	1,587	$	10,480

Other Postretirement Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Net periodic benefit cost for pension and other postretirement benefit plans

The following table shows the components of the net periodic benefit cost for the third fiscal quarters of 2018 and 2017 for the Company's other postretirement benefit plans:

	Fiscal quarter ended September 29, 2018					Fiscal quarter ended September 30, 2017
	U.S. Plans			Non-U.S. Plans		U.S. Plans			Non-U.S. Plans

Service cost	$	35		$	71	$	33		$	71
Interest cost		69			28		77			26
Amortization of prior service (credit)		(37	)		-		(209	)		-
Amortization of losses (gains)		(10	)		26		(24	)		16
Net periodic benefit cost	$	57		$	125	$	(123	)	$	113

	Nine fiscal months ended September 29, 2018					Nine fiscal months ended September 30, 2017
	U.S. Plans			Non-U.S. Plans		U.S. Plans			Non-U.S. Plans

Service cost	$	103		$	219	$	99		$	202
Interest cost		205			86		232			76
Amortization of prior service (credit)		(111	)		-		(627	)		-
Amortization of losses (gains)		(29	)		80		(70	)		45
Net periodic benefit cost	$	168		$	385	$	(366	)	$	323

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 29, 2018

Stock-Based Compensation [Abstract]

Summary of recognized stock-based compensation expense

The following table summarizes stock-based compensation expense recognized:

	Fiscal quarters ended				Nine fiscal months ended
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017

Restricted stock units	$	778	$	676	$	3,825		3,556
Phantom stock units		-		-		214		163
Total	$	778	$	676	$	4,039		3,719

Schedule of unrecognized compensation cost, nonvested awards

The following table summarizes unrecognized compensation cost and the weighted average remaining amortization periods at September 29, 2018 (amortization periods in years):

	Unrecognized Compensation Cost		Weighted Average Remaining Amortization Periods

Restricted stock units	$	3,838		1.2
Phantom stock units		-		0.0
Total	$	3,838

Schedule of share-based compensation, restricted stock units award activity

RSU activity under the 2007 Program as of September 29, 2018 and changes during the nine fiscal months then ended are presented below (number of RSUs in thousands):

	Number of RSUs			Weighted Average Grant-date Fair Value per Unit
Outstanding:
January 1, 2018		986		$	13.34
Granted		252			18.90
Vested*		(334	)		13.67
Cancelled or forfeited		-			-
Outstanding at September 29, 2018		904		$	14.77

Expected to vest at September 29, 2018		904

* The number of RSUs vested includes shares that the Company withheld on behalf of employees to satisfy the statutory tax withholding requirements.

Schedule of share-based compensation arrangement by share-based units, vested and expected to vest

Vesting Date	Expected to Vest		Not Expected to Vest		Total
January 1, 2019		213		-		213
January 1, 2020		167		-		167
January 1, 2021		141		-		141

Schedule of share-based compensation, phantom stock units, Activity

	Number of units		Grant-date Fair Value per Unit
Outstanding:
January 1, 2018		157
Granted		10	$	21.35
Dividend equivalents issued		2
Outstanding at September 29, 2018		169

Segment Information (Tables)

9 Months Ended

Sep. 29, 2018

Segment Information [Abstract]

Schedule of Segment Reporting Information, by Segment

The following tables set forth business segment information:

	MOSFETs		Diodes		Optoelectronic Components		Resistors & Inductors		Capacitors		Total
Fiscal quarter ended September 29, 2018:
Product Sales	$	144,227	$	186,492	$	76,443	$	257,330	$	116,447	$	780,939
Royalty Revenues		33		-		-		-		-	$	33
Total Revenue	$	144,260	$	186,492	$	76,443	$	257,330	$	116,447	$	780,972

Gross Profit	$	38,991	$	54,690	$	27,653	$	88,213	$	26,749	$	236,296

Segment Operating Income	$	29,502	$	49,561	$	23,144	$	80,042	$	21,655	$	203,904

Fiscal quarter ended September 30, 2017:*
Product Sales	$	126,522	$	160,562	$	77,145	$	217,489	$	96,215	$	677,933
Royalty Revenues		-		-		-		8		-	$	8
Total Revenue	$	126,522	$	160,562	$	77,145	$	217,497	$	96,215	$	677,941

Gross Profit	$	32,349	$	43,575	$	29,042	$	65,586	$	19,595	$	190,147

Segment Operating Income	$	23,434	$	38,694	$	25,214	$	58,328	$	14,705	$	160,375

Nine fiscal months ended September 29, 2018:
Product Sales	$	408,280	$	535,975	$	224,110	$	755,262	$	335,064	$	2,258,691
Royalty Revenues		45		-		-		61		-	$	106
Total Revenue	$	408,325	$	535,975	$	224,110	$	755,323	$	335,064	$	2,258,797

Gross Profit	$	109,440	$	150,298	$	81,290	$	251,712	$	76,094	$	668,834

Segment Operating Income	$	80,577	$	134,592	$	68,103	$	226,292	$	60,258	$	569,822

Nine fiscal months ended September 30, 2017:*
Product Sales	$	345,399	$	460,492	$	215,040	$	626,684	$	278,241	$	1,925,856
Royalty Revenues		-		-		-		50		-	$	50
Total Revenue	$	345,399	$	460,492	$	215,040	$	626,734	$	278,241	$	1,925,906

Gross Profit	$	78,423	$	123,499	$	77,091	$	188,936	$	57,784	$	525,733

Segment Operating Income	$	51,917	$	109,014	$	64,007	$	167,035	$	43,041	$	435,014

*Recast for the retrospective adoption of ASUs 2014-09 and 2017-07. See Note 1.

Reconciliation of Operating Profit (Loss) from Segments to Consolidated

	Fiscal quarters ended						Nine fiscal months ended
	September 29, 2018			September 30, 2017***			September 29, 2018			September 30, 2017***
Reconciliation:
Segment Operating Income	$	203,904		$	160,375		$	569,822		$	435,014
Restructuring and Severance Costs		-			(3,244	)		-			(5,194	)
Unallocated Selling, General, and Administrative Expenses		(65,806	)		(61,715	)		(204,369	)		(181,821	)
Consolidated Operating Income	$	138,098		$	95,416		$	365,453		$	247,999
Unallocated Other Income (Expense)		(11,290	)		(9,228	)		(49,067	)		(35,660	)
Consolidated Income Before Taxes	$	126,808		$	86,188		$	316,386		$	212,339

***Recast for the adoption of ASU 2017-07. See Note 1.

Disaggregation of Revenue [Table Text Block]

The Company has a broad line of products that it sells to OEMs, EMS companies, and independent distributors. The distribution of sales by customer type is shown below:

	Fiscal quarters ended				Nine fiscal months ended				Years Ended December 31,
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017		2017		2016
Distributors	$	452,051	$	383,727	$	1,302,127	$	1,102,232	$	1,484,276	$	1,280,060
OEMs		276,299		247,551		803,128		685,565		931,291		861,322
EMS companies		52,622		46,663		153,542		138,109		183,801		175,946
Total Revenue	$	780,972	$	677,941	$	2,258,797	$	1,925,906	$	2,599,368	$	2,317,328

Net revenues were attributable to customers in the following regions:

	Fiscal quarters ended				Nine fiscal months ended				Years Ended December 31,
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017		2017		2016
Asia	$	315,701	$	282,416	$	904,047	$	811,987	$	1,091,107	$	948,195
Europe		269,518		237,874		809,501		665,049		902,357		810,543
Americas		195,753		157,651		545,249		448,870		605,904		558,590
Total Revenue	$	780,972	$	677,941	$	2,258,797	$	1,925,906	$	2,599,368	$	2,317,328

	Fiscal quarters ended				Nine fiscal months ended				Years Ended December 31,
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017		2017		2016
Industrial	$	283,134	$	242,038	$	858,963	$	691,678	$	934,631	$	796,031
Automotive		224,041		185,781		642,293		537,008		727,220		640,767
Telecommunications		51,935		50,710		144,326		143,828		190,682		193,456
Computing		62,774		55,380		163,862		143,948		198,850		172,481
Consumer Products		48,583		40,155		126,781		108,711		145,243		150,741
Power Supplies		34,899		44,327		110,468		120,223		160,038		132,555
Military and Aerospace		41,881		33,029		117,355		98,753		132,898		128,523
Medical		33,725		26,521		94,749		81,757		109,806		102,774
Total revenue	$	780,972	$	677,941		2,258,797		1,925,906	$	2,599,368	$	2,317,328

Earnings Per Share (Tables)

9 Months Ended

Sep. 29, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table sets forth the computation of basic and diluted earnings (loss) per share attributable to Vishay stockholders (shares in thousands):

	Fiscal quarters ended				Nine fiscal months ended
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017

Numerator:
Net earnings attributable to Vishay stockholders	$	77,876	$	64,404	$	243,339	$	157,313

Denominator:
Denominator for basic earnings per share:
Weighted average shares		144,215		145,572		144,197		145,973
Outstanding phantom stock units		168		156		167		155
Adjusted weighted average shares		144,383		145,728		144,364		146,128

Effect of dilutive securities:
Convertible and exchangeable debt instruments		8,062		10,480		11,827		9,160
Restricted stock units		501		493		511		338
Dilutive potential common shares		8,563		10,973		12,338		9,498

Denominator for diluted earnings per share:
Adjusted weighted average shares - diluted		152,946		156,701		156,702		155,626

Basic earnings per share attributable to Vishay stockholders	$	0.54	$	0.44	$	1.69	$	1.08

Diluted earnings per share attributable to Vishay stockholders	$	0.51	$	0.41	$	1.55	$	1.01

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

	Fiscal quarters ended				Nine fiscal months ended
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017
Convertible debt:
Convertible Senior Debentures, due 2041		-		8,401		-		8,371
Convertible Senior Notes, due 2025		19,052		-		7,607		-
Weighted average other		307		379		307		514

Fair Value Measurements (Tables)

9 Months Ended

Sep. 29, 2018

Fair Value Measurements [Abstract]

Schedule of fair Value, Assets and Liabilities Measured on Recurring basis

The following table provides the financial assets and liabilities carried at fair value measured on a recurring basis:

	Total Fair Value			Level 1		Level 2		Level 3
September 29, 2018
Assets:
Assets held in rabbi trusts	$	43,701		$	26,363	$	17,338	$	-
Available for sale securities	$	4,429			4,429		-		-
	$	48,130		$	30,792	$	17,338	$	-
Liabilities:
Embedded derivative - convertible debentures due 2040	$	(47	)	$	-	$	-	$	(47	)
Embedded derivative - convertible debentures due 2041	$	(244	)		-		-		(244	)
Embedded derivative - convertible debentures due 2042	$	(63	)		-		-		(63	)
	$	(354	)	$	-	$	-	$	(354	)
December 31, 2017
Assets:
Assets held in rabbi trusts	$	45,252		$	28,589		16,663	$	-
Available for sale securities	$	4,621			4,621		-		-
	$	49,873		$	33,210	$	16,663	$	-
Liabilities:
Embedded derivative - convertible debentures due 2040	$	(206	)	$	-	$	-	$	(206	)
Embedded derivative - convertible debentures due 2041	$	(214	)		-		-		(214	)
Embedded derivative - convertible debentures due 2042	$	(118	)		-		-		(118	)
	$	(538	)	$	-	$	-	$	(538	)

Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
Basis of Presentation (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues	$ 780,972	$ 673,462	$ 677,941	$ 643,164	$ 604,801	$ 2,258,797	$ 1,925,906	$ 2,599,368	$ 2,317,328
Costs of products sold	544,676	496,086	487,794	469,327	443,052	1,589,963	1,400,173	1,896,259	1,743,506
Gross profit	236,296	177,376	190,147	173,837	161,749	668,834	525,733	703,109	573,822
Operating Income	138,098	76,006	95,416	85,005	67,578	365,453	247,999	324,005	197,058
Total other income (expense)	(11,290)	(8,981)	(9,228)	(9,296)	(17,136)	(49,067)	(35,660)	(44,641)	(102,842)
Income before taxes	126,808	67,025	86,188	75,709	50,442	316,386	212,339	279,364	94,216
Income tax expense	48,737	244,526	21,605	19,300	13,493	72,508	54,398	298,924	44,843
Net earnings (loss)	78,071	(177,501)	64,583	56,409	36,949	243,878	157,941	(19,560)	49,373
Less: net earnings attributable to noncontrolling interests	195	156	179	219	230	539	628	784	581
Net earnings (loss) attributable to Vishay stockholders	$ 77,876	(177,657)	64,404	56,190	36,719	$ 243,339	$ 157,313	(20,344)	48,792
Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues		674,489	677,883	644,892	606,258			2,603,522	2,323,431
Costs of products sold		497,988	488,610	471,929	445,383			1,903,910	1,753,648
Gross profit		176,501	189,273	172,963	160,875			699,612	569,783
Operating Income		72,536	92,328	82,036	64,688			311,588	101,717
Total other income (expense)		(5,511)	(6,140)	(6,327)	(14,246)			(32,224)	(7,501)
Income before taxes		67,025	86,188	75,709	50,442			279,364	94,216
Income tax expense		244,526	21,605	19,300	13,493			298,924	44,843
Net earnings (loss)		(177,501)	64,583	56,409	36,949			(19,560)	49,373
Less: net earnings attributable to noncontrolling interests		156	179	219	230			784	581
Net earnings (loss) attributable to Vishay stockholders		(177,657)	64,404	56,190	36,719			(20,344)	48,792
Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net revenues		(1,027)	58	(1,728)	(1,457)			(4,154)	(6,103)
Costs of products sold		(1,902)	(816)	(2,602)	(2,331)			(7,651)	(10,142)
Gross profit		875	874	874	874			3,497	4,039
Operating Income		3,470	3,088	2,969	2,890			12,417	95,341
Total other income (expense)		(3,470)	(3,088)	(2,969)	(2,890)			(12,417)	(95,341)
Income before taxes		0	0	0	0			0	0
Income tax expense		0	0	0	0			0	0
Net earnings (loss)		0	0	0	0			0	0
Less: net earnings attributable to noncontrolling interests		0	0	0	0			0	0
Net earnings (loss) attributable to Vishay stockholders		$ 0	$ 0	$ 0	$ 0			$ 0	0
U.S. pension settlement charges									$ (79,321)

Revenue Recognition Policies (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Distributor sales accruals [Line Items]
Beginning Balance	$ 38,032	$ 35,733	$ 36,680	$ 34,479	$ 34,479	$ 32,487
Sales allowances	27,986	22,421	77,539	67,191	89,009	86,896
Credits issued	(29,293)	(28,116)	(77,091)	(71,638)	(87,403)	(85,341)
Foreign currency	103	384	(300)	390	595	437
Ending Balance	$ 36,828	$ 30,422	$ 36,828	$ 30,422	$ 36,680	$ 34,479

Acquisition Activities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Acquisition Activities (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Mar. 31, 2018	Sep. 29, 2018	Sep. 30, 2017
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Acquisition of business, net of cash acquired			$ 14,880	$ 0
UltraSource [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Purchase price of businesses		$ 13,596
Finite-lived Intangible Assets Acquired		6,500
Goodwill related to acquisitions		$ 4,227
Business Acquisition, Name of Acquired Entity		UltraSource, Inc.
Business Acquisition, Effective Date of Acquisition		Feb. 08, 2018
EuroPower [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Purchase price of businesses	$ 2,939
Goodwill related to acquisitions	$ 1,068
Business Acquisition, Name of Acquired Entity	EuroPower Holdings Ltd.
Business Acquisition, Effective Date of Acquisition	Jun. 11, 2018

Restructuring and Related Activities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Reserve [Roll Forward]
Restructuring and severance costs	$ 0	$ 3,244	$ 0	$ 5,194
MOSFETs Enhanced Competitiveness Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Current	1,212		1,212
Restructuring Reserve [Roll Forward]
Restructuring and severance costs		2,463		2,911	$ 3,204	$ 9,744	$ 5,367	$ 6,025	$ 2,328
Cash paid			(1,051)		(7,173)	(15,686)	(426)	(856)	(267)
Foreign currency translation						2	1
Balance at end of period	$ 1,212		1,212		2,263	6,232	12,172	7,230	$ 2,061
Balance at beginning of period			2,263	6,232	6,232	12,172	7,230	$ 2,061
Term of restructuring program	2 years
Global Cost Reduction Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Current	$ 2,772		2,772
Restructuring Reserve [Roll Forward]
Restructuring and severance costs		781		2,283	8,069	9,918	13,753
Cash paid			(2,881)		(7,168)	(16,237)	(986)
Foreign currency translation			(87)		500	(34)	(150)
Balance at end of period	$ 4,697		4,697		7,665	6,264	$ 12,617
Balance at beginning of period			$ 7,665	6,264	$ 6,264	$ 12,617
Global Cost Reduction Program [Member] \| Diodes Segment [Member]
Restructuring Reserve [Roll Forward]
Restructuring and severance costs		(13)		0
Global Cost Reduction Program [Member] \| Optoelectronic Components Segment [Member]
Restructuring Reserve [Roll Forward]
Restructuring and severance costs		0		242
Global Cost Reduction Program [Member] \| Resistors And Inductors Segment [Member]
Restructuring Reserve [Roll Forward]
Restructuring and severance costs		468		1,403
Global Cost Reduction Program [Member] \| Capacitors Segment [Member]
Restructuring Reserve [Roll Forward]
Restructuring and severance costs		88		334
Global Cost Reduction Program [Member] \| Unallocated Amount to Segment [Member]
Restructuring Reserve [Roll Forward]
Restructuring and severance costs		$ 238		$ 304

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Taxes [Abstract]
Increase in liabilities for unrecognized tax benefits				$ 3,486
TCJA income tax expense Abstract [Abstract]
TCJA tax on unremitted foreign earnings	$ 6,214					$ 215,558
TCJA foreign taxes on assumed repatriation				19,282		213,000
Expected TCJA tax payment, net	184,468			184,468
Additional expected repatriation	1,200,000					$ 1,100,000
Cash repatriated during the current period	450,000	$ 274,000
Repatriation taxes paid	64,674	92,093
TCJA transition taxes paid		14,400
Future cash repatriation [Abstract]
Future cash repatriation following next fiscal quarter	300,000			300,000
Remeasurement of repatriation deferred tax liability [Member]
Effect on Income Tax Expense (Benefit) [Line Items]
Deferred Other Tax Expense (Benefit)	$ 680		$ 892	$ (7,010)	$ 3,100
Remeasurement of deferred tax liability debt extinguishment [Member]
Effect on Income Tax Expense (Benefit) [Line Items]
Deferred Other Tax Expense (Benefit)		$ (33,963)

Long-Term Debt (Details) $ / shares in Units, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 29, 2018 USD ($) $ / shares	Jun. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 29, 2018 USD ($) $ / shares	Sep. 30, 2017 USD ($)	Jun. 08, 2018 $ / shares	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Credit facility	$ 0			$ 0			$ 150,000
Deferred Financing Costs	(17,716)			(17,716)			(9,101)
Long-term debt	588,586			588,586			370,470
Less current portion	0			0			0
Long-term debt, less current portion	$ 588,586			$ 588,586			370,470
Debt Instruments [Abstract]
Debt instrument percentage of conversion price (in hundredths)				130.00%
Debt instrument, Percentage of sale price of common stock (in hundredths)	98.00%			98.00%
Purchase price of extinguished debt		$ 584,991
Liability and equity components of convertible debentures [Abstract]
Principal amount of the debentures	$ 285,940			$ 285,940			575,000
Unamortized discount	(171,845)			(171,845)			(345,967)
Embedded derivative	354			354			538
Carrying value of liability component	114,449			114,449			229,571
Equity component - net carrying value	115,494			115,494			230,214
Interest expense related to debentures [Abstract]
Non-cash amortization of debt discount				6,966	$ 3,703
Stock price per share (in dollars per share) \| $ / shares						$ 24.70
Allocated liability component of repurchased debt		133,647
Allocated equity component of repurchased debt		451,344
Convertible Senior Debentures, Due 2040 [Member]
Debt Instrument [Line Items]
Convertible Debt, Noncurrent	$ 22,486			$ 22,486			110,412
Debt Instruments [Abstract]
Issuance date				Nov. 09, 2010
Debt maturity date				Nov. 15, 2040
Stated rate of interest on debt (in hundredths)	2.25%			2.25%
Effective rate of interest on convertible senior debentures (in hundredths)	8.00%			8.00%
Debt conversion rate	78.0506
Debt effective conversion price \| $ / shares	$ 12.81			$ 12.81
Debt Instrument, Convertible, Stock Price Trigger \| $ / shares				$ 16.65
Convertible senior debentures call date	Nov. 20, 2020
Principal amount of repurchased debt		220,000
Liability and equity components of convertible debentures [Abstract]
Principal amount of the debentures	$ 55,000			$ 55,000			275,000
Unamortized discount	(32,561)			(32,561)			(164,794)
Embedded derivative	47			47			206
Carrying value of liability component	22,486			22,486			110,412
Equity component - net carrying value	22,019			22,019			110,094
Interest expense related to debentures [Abstract]
Contractual coupon interest	310		$ 1,547	2,991	4,641
Non-cash amortization of debt discount	135		626	1,269	1,841
Non-cash amortization of deferred financing costs	4		22	42	66
Non-cash change in value of derivative liability	20		(53)	81	(97)
Total interest expense related to the debentures	469		2,142	4,383	6,451
Net carrying value of repurchased debt		89,276
Convertible Senior Debentures, Due 2041 [Member]
Debt Instrument [Line Items]
Convertible Debt, Noncurrent	$ 57,695			$ 57,695			56,641
Debt Instruments [Abstract]
Issuance date				May 13, 2011
Debt maturity date				May 15, 2041
Stated rate of interest on debt (in hundredths)	2.25%			2.25%
Effective rate of interest on convertible senior debentures (in hundredths)	8.375%			8.375%
Debt conversion rate	56.9573
Debt effective conversion price \| $ / shares	$ 17.56			$ 17.56
Debt Instrument, Convertible, Stock Price Trigger \| $ / shares				$ 22.83
Convertible senior debentures call date	May 20, 2021
Liability and equity components of convertible debentures [Abstract]
Principal amount of the debentures	$ 150,000			$ 150,000			150,000
Unamortized discount	(92,549)			(92,549)			(93,573)
Embedded derivative	244			244			214
Carrying value of liability component	57,695			57,695			56,641
Equity component - net carrying value	62,246			62,246			62,246
Interest expense related to debentures [Abstract]
Contractual coupon interest	844		844	2,532	2,532
Non-cash amortization of debt discount	349		321	1,024	943
Non-cash amortization of deferred financing costs	12		11	36	35
Non-cash change in value of derivative liability	71		(21)	30	(13)
Total interest expense related to the debentures	1,276		1,155	3,622	3,497
Convertible Senior Debentures, Due 2042 [Member]
Debt Instrument [Line Items]
Convertible Debt, Noncurrent	$ 34,268			$ 34,268			62,518
Debt Instruments [Abstract]
Issuance date				May 31, 2012
Debt maturity date				Jun. 01, 2042
Stated rate of interest on debt (in hundredths)	2.25%			2.25%
Effective rate of interest on convertible senior debentures (in hundredths)	7.50%			7.50%
Debt conversion rate	91.7689
Debt effective conversion price \| $ / shares	$ 10.90			$ 10.90
Debt Instrument, Convertible, Stock Price Trigger \| $ / shares				$ 14.17
Convertible senior debentures call date	Jun. 07, 2022
Principal amount of repurchased debt		69,060
Liability and equity components of convertible debentures [Abstract]
Principal amount of the debentures	$ 80,940			$ 80,940			150,000
Unamortized discount	(46,735)			(46,735)			(87,600)
Embedded derivative	63			63			118
Carrying value of liability component	34,268			34,268			62,518
Equity component - net carrying value	31,229			31,229			57,874
Interest expense related to debentures [Abstract]
Contractual coupon interest	455		844	2,013	2,532
Non-cash amortization of debt discount	184		312	783	919
Non-cash amortization of deferred financing costs	7		13	31	40
Non-cash change in value of derivative liability	19		(21)	4	(13)
Total interest expense related to the debentures	665		1,148	2,831	3,478
Net carrying value of repurchased debt		$ 29,037
Convertible Senior Notes, Due 2025 [Member]
Debt Instrument [Line Items]
Convertible Debt, Noncurrent	$ 491,853			$ 491,853			$ 0
Debt Instruments [Abstract]
Debt maturity date		Jun. 15, 2025
Stated rate of interest on debt (in hundredths)	2.25%			2.25%
Effective rate of interest on convertible senior debentures (in hundredths)	5.50%			5.50%
Debt conversion rate	31.7536
Debt effective conversion price \| $ / shares	$ 31.49			$ 31.49
Debt Instrument, Convertible, Stock Price Trigger \| $ / shares	$ 40.94
Liability and equity components of convertible debentures [Abstract]
Principal amount of the debentures	$ 600,000			$ 600,000
Unamortized discount	(108,147)			(108,147)
Carrying value of liability component	491,853			491,853
Equity component - net carrying value	85,262			85,262
Interest expense related to debentures [Abstract]
Contractual coupon interest	3,375			4,088
Non-cash amortization of debt discount	3,334			3,890
Non-cash amortization of deferred financing costs	454			605
Total interest expense related to the debentures	7,163			8,583
Convertible senior debentures [Member]
Interest expense related to debentures [Abstract]
Contractual coupon interest	1,609		3,235	7,536	9,705
Non-cash amortization of debt discount	668		1,259	3,076	3,703
Non-cash amortization of deferred financing costs	23		46	109	141
Non-cash change in value of derivative liability	110		(95)	115	(123)
Total interest expense related to the debentures	$ 2,410		$ 4,445	$ 10,836	$ 13,426

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance			$ 25,714
Cumulative effect of accounting change for adoption of ASU					$ 0	$ 386	$ 2,210
Other comprehensive income (loss)	$ 5,947	$ 29,661	(25,384)	$ 104,810	120,366	36,675
Ending Balance	(1,471)		(1,471)		25,714
Unrealized Gain (Loss) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance			1,801
Cumulative effect of accounting change for adoption of ASU					(1,801)
Other comprehensive income before reclassifications			0
Tax effect			0
Other comprehensive income before reclassifications, net of tax			0
Amounts reclassified out of AOCI			0
Tax effect of reclassification			0
Amounts reclassified out of AOCI, net of tax			0
Other comprehensive income (loss)			0
Ending Balance	0		0		1,801
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance			92,954
Cumulative effect of accounting change for adoption of ASU					0
Other comprehensive income before reclassifications			(30,236)
Tax effect			0
Other comprehensive income before reclassifications, net of tax			(30,236)
Amounts reclassified out of AOCI			0
Tax effect of reclassification			0
Amounts reclassified out of AOCI, net of tax			0
Other comprehensive income (loss)			(30,236)
Ending Balance	62,718		62,718		92,954
Pension and Other Post-Retirement Actuarial Items [Member]
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance			(69,041)
Cumulative effect of accounting change for adoption of ASU					0
Other comprehensive income before reclassifications			0
Tax effect			0
Other comprehensive income before reclassifications, net of tax			0
Amounts reclassified out of AOCI			6,734
Tax effect of reclassification			(1,882)
Amounts reclassified out of AOCI, net of tax			4,852
Other comprehensive income (loss)			4,852
Ending Balance	(64,189)		(64,189)		(69,041)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income [Line Items]
Beginning Balance			25,714
Cumulative effect of accounting change for adoption of ASU					(1,801)	0	$ 0
Other comprehensive income before reclassifications			(30,236)
Tax effect			0
Other comprehensive income before reclassifications, net of tax			(30,236)
Amounts reclassified out of AOCI			6,734
Tax effect of reclassification			(1,882)
Amounts reclassified out of AOCI, net of tax			4,852
Other comprehensive income (loss)			(25,384)		120,366	$ 36,675
Ending Balance	$ (1,471)		$ (1,471)		$ 25,714

Pensions and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Defined Benefit Pension Plan [Member] \| Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	371	411	1,113	1,232
Expected return on plan assets	0	0	0	0
Amortization of prior service cost (credit)	36	36	108	108
Amortization of losses (gains)	159	82	477	247
Curtailments and settlements	0	0	0	0
Net periodic benefit cost	566	529	1,698	1,587
Defined Benefit Pension Plan [Member] \| Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost	900	948	2,775	2,776
Interest cost	1,175	1,247	3,628	3,613
Expected return on plan assets	(463)	(519)	(1,430)	(1,543)
Amortization of prior service cost (credit)	52	19	161	55
Amortization of losses (gains)	1,520	1,595	4,690	4,596
Curtailments and settlements	441	331	1,358	983
Net periodic benefit cost	3,625	3,621	11,182	10,480
Other Postretirement Benefits [Member] \| Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost	35	33	103	99
Interest cost	69	77	205	232
Amortization of prior service cost (credit)	(37)	(209)	(111)	(627)
Amortization of losses (gains)	(10)	(24)	(29)	(70)
Net periodic benefit cost	57	(123)	168	(366)
Other Postretirement Benefits [Member] \| Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost	71	71	219	202
Interest cost	28	26	86	76
Amortization of prior service cost (credit)	0	0	0	0
Amortization of losses (gains)	26	16	80	45
Net periodic benefit cost	$ 125	$ 113	$ 385	$ 323

Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

9 Months Ended

Sep. 29, 2018

Sep. 30, 2017

Sep. 29, 2018

Sep. 30, 2017

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-based compensation expense recognized

$ 778

$ 676

$ 4,039

$ 3,719

Unrecognized Compensation Cost

$ 3,838

Expiration date of the 2007 stock incentive plan

May 20, 2024

Maximum number of shares granted under restricted stock, unrestricted stock, RSU's and stock options to officers, employees and employee directors (in shares)

6,500,000

Restricted Stock Units (RSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-based compensation expense recognized

$ 778

676

$ 3,825

3,556

Unrecognized Compensation Cost

$ 3,838

Weighted Average Remaining Amortization Periods

1 year 2 months 12 days

Equity Awards Other Than Options Outstanding:

Balance (in shares)

986,000

Balance (in dollars per share)

$ 13.34

Granted (in shares)

252,000

Granted (in dollars per share)

$ 18.90

Vested (in shares)

^[1]

(334,000)

Vested (in dollars per share)

^[1]

$ 13.67

Cancelled or forfeited (in shares)

Cancelled or forfeited (in dollars per share)

$ 0

Balance (in shares)

904,000

Balance (in dollars per share)

$ 14.77

Expected to vest (in shares)

904,000

Phantom Share Units (PSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-based compensation expense recognized

$ 0

$ 214

$ 163

Unrecognized Compensation Cost

$ 0

Weighted Average Remaining Amortization Periods

0 years

Equity Awards Other Than Options Outstanding:

Balance (in shares)

157,000

Granted (in shares)

10,000

Granted (in dollars per share)

$ 21.35

Dividend equivalents issued

2,000

Balance (in shares)

169,000

Scheduled to Vest January 1, 2019 [Member] | Performance Vested Restricted Stock Units [Member]

Equity Awards Other Than Options Outstanding:

Balance (in shares)

213,000

Expected to vest (in shares)

213,000

Not expected to vest (in shares)

Scheduled to Vest January 1, 2020 [Member] | Performance Vested Restricted Stock Units [Member]

Equity Awards Other Than Options Outstanding:

Balance (in shares)

167,000

Expected to vest (in shares)

167,000

Not expected to vest (in shares)

Scheduled to Vest January 1, 2021 [Member] | Performance Vested Restricted Stock Units [Member]

Equity Awards Other Than Options Outstanding:

Balance (in shares)

141,000

Expected to vest (in shares)

141,000

Not expected to vest (in shares)

[1]	The number of RSUs vested includes shares that the Company withheld on behalf of employees to satisfy the statutory tax withholding requirements.

Segment Information (Details) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
Segment Information (Details) $ in Thousands	Sep. 29, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jul. 01, 2017 USD ($)	Apr. 01, 2017 USD ($)	Sep. 29, 2018 USD ($) Segment	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment						5
Product Sales	$ 780,939		$ 677,933			$ 2,258,691	$ 1,925,856
Royalty Revenues	33		8			106	50
Total Revenue	780,972	$ 673,462	677,941	$ 643,164	$ 604,801	2,258,797	1,925,906	$ 2,599,368	$ 2,317,328
Gross Margin	236,296	177,376	190,147	173,837	161,749	668,834	525,733	703,109	573,822
Segment Operating Income	203,904		160,375			569,822	435,014
Restructuring and severance Costs	0		(3,244)			0	(5,194)
Operating income	138,098	76,006	95,416	85,005	67,578	365,453	247,999	324,005	197,058
Unallocated Other Income (Expense)	(11,290)	(8,981)	(9,228)	(9,296)	(17,136)	(49,067)	(35,660)	(44,641)	(102,842)
Income before taxes	126,808	$ 67,025	86,188	$ 75,709	$ 50,442	316,386	212,339	279,364	94,216
Distributors [Member]
Segment Reporting Information [Line Items]
Total Revenue	452,051		383,727			1,302,127	1,102,232	1,484,276	1,280,060
OEMs [Member]
Segment Reporting Information [Line Items]
Total Revenue	276,299		247,551			803,128	685,565	931,291	861,322
EMS companies [Member]
Segment Reporting Information [Line Items]
Total Revenue	52,622		46,663			153,542	138,109	183,801	175,946
Industrial [Member]
Segment Reporting Information [Line Items]
Total Revenue	283,134		242,038			858,963	691,678	934,631	796,031
Automotive [Member]
Segment Reporting Information [Line Items]
Total Revenue	224,041		185,781			642,293	537,008	727,220	640,767
Telecommunications [Member]
Segment Reporting Information [Line Items]
Total Revenue	51,935		50,710			144,326	143,828	190,682	193,456
Computing [Member]
Segment Reporting Information [Line Items]
Total Revenue	62,774		55,380			163,862	143,948	198,850	172,481
Consumer Products [Member]
Segment Reporting Information [Line Items]
Total Revenue	48,583		40,155			126,781	108,711	145,243	150,741
Power Supplies [Member]
Segment Reporting Information [Line Items]
Total Revenue	34,899		44,327			110,468	120,223	160,038	132,555
Military and Aerospace [Member]
Segment Reporting Information [Line Items]
Total Revenue	41,881		33,029			117,355	98,753	132,898	128,523
Medical [Member]
Segment Reporting Information [Line Items]
Total Revenue	33,725		26,521			94,749	81,757	109,806	102,774
Asia [Member]
Segment Reporting Information [Line Items]
Total Revenue	315,701		282,416			904,047	811,987	1,091,107	948,195
Americas [Member]
Segment Reporting Information [Line Items]
Total Revenue	195,753		157,651			545,249	448,870	605,904	558,590
Europe [Member]
Segment Reporting Information [Line Items]
Total Revenue	269,518		237,874			809,501	665,049	$ 902,357	$ 810,543
MOSFETS Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	144,227		126,522			408,280	345,399
Royalty Revenues	33		0			45	0
Total Revenue	144,260		126,522			408,325	345,399
Gross Margin	38,991		32,349			109,440	78,423
Segment Operating Income	29,502		23,434			80,577	51,917
Diodes Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	186,492		160,562			535,975	460,492
Royalty Revenues	0		0			0	0
Total Revenue	186,492		160,562			535,975	460,492
Gross Margin	54,690		43,575			150,298	123,499
Segment Operating Income	49,561		38,694			134,592	109,014
Optoelectronic Components Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	76,443		77,145			224,110	215,040
Royalty Revenues	0		0			0	0
Total Revenue	76,443		77,145			224,110	215,040
Gross Margin	27,653		29,042			81,290	77,091
Segment Operating Income	23,144		25,214			68,103	64,007
Resistors And Inductors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	257,330		217,489			755,262	626,684
Royalty Revenues	0		8			61	50
Total Revenue	257,330		217,497			755,323	626,734
Gross Margin	88,213		65,586			251,712	188,936
Segment Operating Income	80,042		58,328			226,292	167,035
Capacitors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	116,447		96,215			335,064	278,241
Royalty Revenues	0		0			0	0
Total Revenue	116,447		96,215			335,064	278,241
Gross Margin	26,749		19,595			76,094	57,784
Segment Operating Income	21,655		14,705			60,258	43,041
Unallocated Amount to Segment [Member]
Segment Reporting Information [Line Items]
Segment Operating Income	(65,806)		(61,715)			(204,369)	(181,821)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment Operating Income	203,904		160,375			569,822	435,014
Unallocated Amount to Segment [Member]
Segment Reporting Information [Line Items]
Restructuring and severance Costs	0		(3,244)			0	(5,194)
Unallocated Other Income (Expense)	$ (11,290)		$ (9,228)			$ (49,067)	$ (35,660)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 29, 2018	Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Numerator for basic earnings per share:
Net earnings attributable to Vishay stockholders	$ 77,876	$ (177,657)	$ 64,404	$ 56,190	$ 36,719	$ 243,339	$ 157,313	$ (20,344)	$ 48,792
Denominator for basic earnings per share:
Weighted average shares	144,215		145,572			144,197	145,973
Outstanding phantom stock units	168		156			167	155
Adjusted weighted average shares (basic)	144,383		145,728			144,364	146,128
Effect of dilutive securities:
Convertible and exchangeable debt instruments	8,062		10,480			11,827	9,160
Restricted stock units	501		493			511	338
Dilutive potential common shares	8,563		10,973			12,338	9,498
Denominator for diluted earnings per share:
Adjusted weighted average shares (diluted)	152,946		156,701			156,702	155,626
Basic earnings per share attributable to Vishay stockholders (in dollars per share)	$ 0.54		$ 0.44			$ 1.69	$ 1.08
Diluted earnings per share attributable to Vishay stockholders (in dollars per share)	0.51		$ 0.41			1.55	$ 1.01
Convertible Senior Debentures, Due 2040 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Minimum market price of common stock for inclusion of shares issuable upon conversion of senior debentures for calculation of diluted earnings per share (in dollars per share)	$ 12.81					$ 12.81
Convertible Senior Debentures, Due 2041 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount (in shares)	0		8,401			0	8,371
Minimum market price of common stock for inclusion of shares issuable upon conversion of senior debentures for calculation of diluted earnings per share (in dollars per share)	$ 17.56					$ 17.56
Convertible Senior Debentures, Due 2042 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Minimum market price of common stock for inclusion of shares issuable upon conversion of senior debentures for calculation of diluted earnings per share (in dollars per share)	$ 10.90					$ 10.90
Weighted average other [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount (in shares)	307		379			307	514
Convertible Senior Notes, Due 2025 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount (in shares)	19,052		0			7,607	0
Minimum market price of common stock for inclusion of shares issuable upon conversion of senior debentures for calculation of diluted earnings per share (in dollars per share)	$ 31.49					$ 31.49

Fair Value Measurements (Details) - USD ($) $ in Thousands	9 Months Ended
Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 31, 2017
Assets:
Held-to-maturity Securities, Transferred Security, at Carrying Value	$ 0
Held-to-maturity Securities, Unrecognized Holding Gain	0
Other than Temporary Impairment Losses, Investments, Held-to-maturity Securities	0
Liabilities:
Embedded derivative	(354)	$ (538)
Long-term Debt, Fair Value	989,400	1,071,200
Carrying value of long-term debt, excluding derivative liabilities	605,948	379,033
Derivative, Notional Amount	0	100,000
Fair Value, Measurements, Recurring [Member]
Assets:
Assets held in rabbi trusts	43,701	45,252
Available for sale securities	4,429	4,621
Fair Value Assets	48,130	49,873
Liabilities:
Fair Value Liabilities	(354)	(538)
Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets:
Assets held in rabbi trusts	26,363	28,589
Available for sale securities	4,429	4,621
Fair Value Assets	30,792	33,210
Liabilities:
Fair Value Liabilities	0	0
Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets:
Assets held in rabbi trusts	17,338	16,663
Available for sale securities	0	0
Fair Value Assets	17,338	16,663
Liabilities:
Fair Value Liabilities	0	0
Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets:
Assets held in rabbi trusts	0	0
Available for sale securities	0	0
Fair Value Assets	0	0
Liabilities:
Fair Value Liabilities	(354)	(538)
Convertible Senior Debentures, Due 2040 [Member]
Liabilities:
Embedded derivative	(47)	(206)
Convertible Senior Debentures, Due 2040 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	(47)	(206)
Convertible Senior Debentures, Due 2040 [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	0	0
Convertible Senior Debentures, Due 2040 [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	0	0
Convertible Senior Debentures, Due 2040 [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	(47)	(206)
Convertible Senior Debentures, Due 2041 [Member]
Liabilities:
Embedded derivative	(244)	(214)
Convertible Senior Debentures, Due 2041 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	(244)	(214)
Convertible Senior Debentures, Due 2041 [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	0	0
Convertible Senior Debentures, Due 2041 [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	0	0
Convertible Senior Debentures, Due 2041 [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	(244)	(214)
Convertible Senior Debentures, Due 2042 [Member]
Liabilities:
Embedded derivative	(63)	(118)
Convertible Senior Debentures, Due 2042 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	(63)	(118)
Convertible Senior Debentures, Due 2042 [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	0	0
Convertible Senior Debentures, Due 2042 [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	0	0
Convertible Senior Debentures, Due 2042 [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities:
Embedded derivative	$ (63)	$ (118)