Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011
Segment Reporting Information [Line Items]
Number of reportable segments			5
Product Sales	$ 571,012	$ 635,821	$ 1,694,306	$ 2,037,895
Royalty Revenues	1,769	1,828	5,221	4,743
Total Revenue	572,781	637,649	1,699,527	2,042,638
Gross Margin	133,554	167,477	417,882	594,330
Gain on Sale of Property	0	0	12,153	0
Operating Income (Loss)	44,459	75,333	167,687	313,036
MOSFETS Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	123,289	131,832	329,316	427,913
Royalty Revenues	36	34	210	196
Total Revenue	123,325	131,866	329,526	428,109
Gross Margin	17,402	27,260	46,728	109,510
Operating Income	7,127	17,314	17,126	79,246
Diodes Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	124,108	150,993	380,250	480,023
Royalty Revenues	0	0	0	0
Total Revenue	124,108	150,993	380,250	480,023
Gross Margin	25,209	35,783	78,939	118,622
Operating Income	19,432	29,220	61,473	99,228
Optoelectronic Components Segments [Member]
Segment Reporting Information [Line Items]
Product Sales	50,205	56,089	158,900	177,556
Royalty Revenues	0	30	27	72
Total Revenue	50,205	56,119	158,927	177,628
Gross Margin	15,563	17,350	51,462	59,259
Operating Income	12,420	13,869	41,657	48,556
Resistors And Inductors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	161,979	155,273	484,136	494,622
Royalty Revenues	1,733	1,764	4,984	4,475
Total Revenue	163,712	157,037	489,120	499,097
Gross Margin	51,254	51,650	160,586	171,764
Operating Income	43,617	44,917	136,817	150,778
Capacitors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	111,431	141,634	341,704	457,781
Royalty Revenues	0	0	0	0
Total Revenue	111,431	141,634	341,704	457,781
Gross Margin	24,126	35,434	80,167	135,175
Operating Income	19,033	29,415	63,901	116,332
Unallocated Amount to Segment [Member]
Segment Reporting Information [Line Items]
Operating Income	(57,170)	(57,529)	(165,440)	(175,342)
Executive Compensation Charge [Member]
Segment Reporting Information [Line Items]
Operating Income	$ 0	$ (1,873)	$ 0	$ (5,762)