Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 25,948	$ 16,820	$ 44,454	$ 32,403
Cash flows hedges [Abstract]
Change in net unrealized gain (loss), net of tax of $10 and $0 in the three-month periods and net of tax of ($6) and $0 in the six-month periods, respectively	(36)	0	(235)	0
Reclassification adjustments for loss (gain) included in net income	24	0	57	0
Net change related to cash flow hedges	(12)	0	(178)	0
Available-for-sale investments
Change in net unrealized gain (loss), net of tax of $69 and ($318) in the three-month periods and net of tax of $182 and ($276) in the six-month periods, respectively	542	(1,279)	1,561	(1,106)
Reclassification adjustments for loss (gain) included in net income	(105)	(52)	(606)	(83)
Net change related to available-for-sale investments	437	(1,331)	955	(1,189)
Currency translation adjustments [Abstract]
Change in currency translation adjustments, net of tax of $53 and $46 in the three-month periods and net of tax of $60 and ($181) in the six-month periods, respectively	(544)	687	(99)	(1,807)
Other comprehensive income (loss), net of tax	(119)	(644)	678	(2,996)
Total comprehensive income	$ 25,829	$ 16,176	$ 45,132	$ 29,407