Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 87,506	$ 41,685	$ 106,841	$ 123,538
Available-for-sale investments:
Net unrealized gain (loss), net of tax of $2,855 and ($5) in the three-month periods and net of tax of $1,067 and $502 in the nine-month periods, respectively	(2,308)	265	6,282	4,827
Reclassification of credit (recovery) loss on investments into current operations	0	0	75	0
Reclassification of net realized (gain) loss into current operations	(786)	(294)	(3,591)	(716)
Net change related to available-for-sale investments	(3,094)	(29)	2,766	4,111
Foreign currency translation adjustments:
Foreign currency translation adjustments	2,098	(1,099)	(3,364)	(1,544)
Other comprehensive income (loss), net of tax	(996)	(1,128)	(598)	2,567
Total comprehensive income	$ 86,510	$ 40,557	$ 106,243	$ 126,105