Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 164,565	$ 119,519	$ 104,488
Other comprehensive income (loss):
Pension and postemployment adjustments, net of tax	877	1,147	(3,261)
Unrealized loss on investments	0	(974)	(815)
Foreign currency translation adjustments	(25,338)	10,738	(24,832)
Comprehensive income	$ 140,104	$ 130,430	$ 75,580