Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 18,506	$ 15,583
Cash flows hedges [Abstract]
Change in net unrealized gain (loss), net of tax of ($16) and $0 in 2014 and 2013, respectively	(166)	0
Reclassification adjustments for loss (gain) included in net income	33	0
Net change related to cash flow hedges	(199)	0
Available-for-sale investments
Change in net unrealized gain (loss), net of tax of $113 and $42 in 2014 and 2013, respectively	518	142
Reclassification of net realized gain on the sale of available-for-sale investments	(501)	(31)
Net change related to available-for-sale investments	1,019	173
Currency translation adjustments [Abstract]
Change in currency translation adjustments, net of tax of $7 and ($227) in 2014 and 2013, respectively	445	(2,494)
Other comprehensive income (loss), net of tax	1,265	(2,321)
Total comprehensive income	$ 19,771	$ 13,262