Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 81,157	$ 64,712	$ 218,543	$ 164,609
Other comprehensive income, net of tax effects:
Foreign currency translation adjustments	3,549	951	13,803	2,858
Changes in unrealized holding gains or losses on available-for-sale securities, net of reclassification adjustment for realized gains and losses	1,000	122	1,248	682
Changes in defined benefit plan liabilities	19	(238)	89	(265)
Total other comprehensive income, net of tax effects	4,568	835	15,140	3,275
Comprehensive income	$ 85,725	$ 65,547	$ 233,683	$ 167,884