Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 41,685	$ 80,436	$ 123,538	$ 173,849
Available-for-sale investments:
Net unrealized gain (loss), net of tax of ($5) and $24 in the three-month periods and net of tax of $502 and ($82) in the nine-month periods, respectively	265	522	4,827	(180)
Reclassification of net realized (gain) loss into current operations	(294)	(266)	(716)	(535)
Net change related to available-for-sale investments	(29)	256	4,111	(715)
Foreign currency translation adjustments:
Foreign currency translation adjustments	(1,099)	(1,881)	(1,544)	(5,078)
Other comprehensive income (loss), net of tax	(1,128)	(1,625)	2,567	(5,793)
Total comprehensive income	$ 40,557	$ 78,811	$ 126,105	$ 168,056