Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 31,336	$ 14,319	$ 99,497	$ 49,098
Available-for-sale marketable securities
Unrealized holding gains (losses) arising during period (Net of deferred taxes of $143 and $67, respectively for the thirteen weeks ended and $575 and $490, respectively for the thirty-nine weeks ended)	362	166	1,479	1,242
Reclassification adjustment for gains included in net income (Net of deferred taxes of $0 and $16, respectively for the thirteen weeks ended and $0 and $16, respectively for the thirty-nine weeks ended)		(39)		(39)
Other comprehensive income gain, net of tax	362	127	1,479	1,203
Comprehensive income, net of tax	$ 31,698	$ 14,446	$ 100,976	$ 50,301