CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012
Statement of Partners' Capital [Abstract]
Net income (loss)	$ 36,766	$ (8,230)	$ 39,387	$ (15,741)
Other comprehensive income (loss), net of tax:
Changes in cumulative translation adjustments	462	403	(8)	317
Foreign currency translation adjustments	462	403	(8)	317
Changes in unrealized gain (loss) on investment arising during the period	52	5	11	30
Gain on investments	52	5	11	30
Other comprehensive income before tax	514	408	3	347
Income tax expense (benefit) related to items of other comprehensive income (loss)	17	3	5	(11)
Other comprehensive income (loss), net of tax	497	405	(2)	358
Comprehensive income (loss)	$ 37,263	$ (7,825)	$ 39,385	$ (15,383)