Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jul. 05, 2015	Jul. 03, 2016	Jul. 05, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 42,759	$ 43,714	$ 57,644	$ 64,216
Cash flow hedges:
Net unrealized gain (loss), net of tax of ($15) and $48 in the three-month periods and net of tax of ($97) and ($25) in the six-month periods, respectively	(302)	237	(879)	(283)
Reclassification of net realized (gain) loss into current operations	190	69	186	179
Net change related to cash flow hedges	(112)	306	(693)	(104)
Available-for-sale investments:
Net unrealized gain (loss), net of tax of $243 and ($128) in the three-month periods and net of tax of $510 and $6 in the six-month periods, respectively	1,351	(333)	2,632	566
Reclassification of net realized (gain) loss into current operations	(141)	(192)	(128)	(221)
Net change related to available-for-sale investments	1,210	(525)	2,504	345
Foreign currency translation adjustments:
Foreign currency translation adjustments, net of tax of ($155) and $107 in the three-month periods and net of tax of $174 and ($529) in the six-month periods, respectively	(2,546)	2,450	2,614	(8,240)
Other comprehensive income (loss), net of tax	(1,448)	2,231	4,425	(7,999)
Total comprehensive income	$ 41,311	$ 45,945	$ 62,069	$ 56,217