Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 29, 2014 Segment	Mar. 30, 2013
Segment Reporting Information [Line Items]
Number of reportable segments	5
Product Sales	$ 601,040	$ 552,274
Royalty Revenues	1,338	1,980
Total Revenue	602,378	554,254
Gross Margin	145,283	136,734
Segment Operating Income	42,572	45,605
Operating Income (Loss)	42,572	45,605
Restructuring and severance Costs	(6,404)	0
MOSFETS Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	113,113	100,846
Royalty Revenues	28	42
Total Revenue	113,141	100,888
Gross Margin	12,617	12,900
Operating Income (Loss)	2,487	2,833
Diodes Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	136,929	125,112
Royalty Revenues	0	0
Total Revenue	136,929	125,112
Gross Margin	29,765	27,261
Operating Income (Loss)	23,058	21,389
Optoelectronic Components Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	57,498	56,226
Royalty Revenues	0	0
Total Revenue	57,498	56,226
Gross Margin	21,237	19,774
Operating Income (Loss)	17,404	16,209
Resistors And Inductors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	187,989	163,928
Royalty Revenues	1,310	1,938
Total Revenue	189,299	165,866
Gross Margin	60,120	52,601
Operating Income (Loss)	50,336	44,200
Capacitors Segment [Member]
Segment Reporting Information [Line Items]
Product Sales	105,511	106,162
Royalty Revenues	0	0
Total Revenue	105,511	106,162
Gross Margin	21,544	24,198
Operating Income (Loss)	15,341	18,456
Unallocated Amount to Segment [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (59,650)	$ (57,482)