Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Segment Reporting Information [Line Items]
Number of reportable segments	5
Product Sales	$ 601,524	$ 571,012	$ 1,749,868	$ 1,694,306
Royalty Revenues	1,366	1,769	4,941	5,221
Total Revenue	602,890	572,781	1,754,809	1,699,527
Gross Margin	143,220	133,554	422,811	417,882
Gain on Sale of Property	0	0	0	12,153
Executive compensation credit (charge)	0	0	1,778	0
Operating Income (Loss)	53,153	44,459	150,648	167,687
MOSFETS Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	115,143	123,289	331,473	329,316
Royalty Revenues	25	36	146	210
Total Revenue	115,168	123,325	331,619	329,526
Gross Margin	15,735	17,402	45,101	46,728
Segment Operating Income	5,313	7,127	13,828	17,126
Diodes Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	140,790	124,108	406,525	380,250
Royalty Revenues	0	0	0	0
Total Revenue	140,790	124,108	406,525	380,250
Gross Margin	32,405	25,209	91,093	78,939
Segment Operating Income	26,240	19,432	72,968	61,473
Optoelectronic Components Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	56,796	50,205	171,419	158,900
Royalty Revenues	51	0	51	27
Total Revenue	56,847	50,205	171,470	158,927
Gross Margin	20,163	15,563	59,088	51,462
Segment Operating Income	16,492	12,420	48,259	41,657
Resistors And Inductors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	176,885	161,979	510,630	484,136
Royalty Revenues	1,290	1,733	4,744	4,984
Total Revenue	178,175	163,712	515,374	489,120
Gross Margin	54,093	51,254	161,039	160,586
Segment Operating Income	45,096	43,617	134,836	136,817
Capacitors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	111,910	111,431	329,821	341,704
Royalty Revenues	0	0	0	0
Total Revenue	111,910	111,431	329,821	341,704
Gross Margin	20,824	24,126	66,490	80,167
Segment Operating Income	14,879	19,033	48,920	63,901
Unallocated Amount to Segment [Member]
Segment Reporting Information [Line Items]
Segment Operating Income	$ (54,867)	$ (57,170)	$ (169,941)	$ (165,440)