Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 72,885	$ 68,259
Other comprehensive income, net of tax effects:
Foreign currency translation adjustments	12,058	2,389
Changes in unrealized holding gains or losses on available-for-sale securities, net of reclassification adjustment for realized gains and losses	0	465
Changes in defined benefit plan liabilities	150	30
Total other comprehensive income, net of tax effects	12,208	2,884
Comprehensive income	$ 85,093	$ 71,143