CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 29, 2013	Mar. 30, 2012
Statement Of Partners Capital [Abstract]
Net income (loss)	$ 6,421	$ (7,528)
Other comprehensive income (loss), net of tax:
Changes in cumulative translation adjustments	(624)	314
Foreign currency translation adjustments	(624)	314
Changes in unrealized gain (loss) on investment arising during the period	5	39
Gain on investments	5	39
Other comprehensive (loss) income before tax	(619)	353
Income tax (benefit) provision related to items of other comprehensive income (loss)	(3)	15
Other comprehensive income (loss), net of tax	(616)	338
Comprehensive income (loss)	$ 5,805	$ (7,190)