Accumulated Other Comprehensive Income - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment income (loss) and interest expense	$ 2,140	$ 3,066	$ 3,752	$ (953)
Provision for income taxes	(12,396)	(14,978)	(20,811)	(24,374)
Net income	$ 33,472	41,472	$ 57,727	$ 68,161
Unrealized Gains (Losses) On Available-For-Sale Marketable Securities [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment income (loss) and interest expense		8
Provision for income taxes		(2)
Net income		$ 6