Segment Information (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2011	Jul. 03, 2010	Jul. 02, 2011	Jul. 03, 2010
Segment Reporting Information [Line Items]
Product Sales	$ 708,279	$ 700,091	$ 1,402,074	$ 1,339,320
Royalty Revenues	1,559	1,564	2,915	2,795
Total Revenue	709,838	701,655	1,404,989	1,342,115
Gross Margin	212,190	210,593	426,853	377,606
MOSFETS Segment
Segment Reporting Information [Line Items]
Product Sales	153,180	153,207	296,081	280,831
Royalty Revenues	65	48	162	48
Total Revenue	153,245	153,255	296,243	280,879
Gross Margin	42,811	46,887	82,250	73,905
Diodes Segment
Segment Reporting Information [Line Items]
Product Sales	169,613	151,026	329,030	291,272
Royalty Revenues	0	0	0	0
Total Revenue	169,613	151,026	329,030	291,272
Gross Margin	43,699	35,865	82,839	63,511
Optoelectronic Components Segments
Segment Reporting Information [Line Items]
Product Sales	63,761	57,657	121,467	116,053
Royalty Revenues	0	27	42	60
Total Revenue	63,761	57,684	121,509	116,113
Gross Margin	21,961	20,288	41,909	39,944
Resistors And Inductors Segment
Segment Reporting Information [Line Items]
Product Sales	167,430	151,941	339,349	299,398
Royalty Revenues	1,494	1,489	2,711	2,687
Total Revenue	168,924	153,430	342,060	302,085
Gross Margin	58,956	54,886	120,114	106,806
Capacitors Segment
Segment Reporting Information [Line Items]
Product Sales	154,295	133,346	316,147	250,677
Royalty Revenues	0	0	0	0
Total Revenue	154,295	133,346	316,147	250,677
Gross Margin	44,763	32,685	99,741	56,410
Vishay Precision Group Segment
Segment Reporting Information [Line Items]
Product Sales	0	52,914	0	101,089
Royalty Revenues	0	0	0	0
Total Revenue	0	52,914	0	101,089
Gross Margin	$ 0	$ 19,982	$ 0	$ 37,030