Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 28, 2019	$ 773,584	$ 326	$ 52,605	$ 720,653
Beginning Balance, Shares at Dec. 28, 2019		32,556,263
Exercise of stock options, shares		2,896
Compensation expense under Incentive Stock Plan	3,966		3,966
Purchase and cancellation of common stock	(17,313)	$ (2)	(421)	(16,890)
Purchase and cancellation of common stock, Shares		(234,116)
Cancellation of non-vested stock, net of issuances	504		504
Cancellation of non-vested stock, net of issuances, shares		(14,782)
Other stock-related activity, net of tax	(295)		239	(534)
Other stock related activity, net of tax, Shares		(5,575)
Net income	70,919			70,919
Ending Balance at Sep. 26, 2020	831,365	$ 324	56,893	774,148
Ending Balance, Shares at Sep. 26, 2020		32,304,686
Beginning Balance at Jun. 27, 2020	807,132	$ 326	55,406	751,400
Beginning Balance, Shares at Jun. 27, 2020		32,440,413
Exercise of stock options, shares		2,886
Compensation expense under Incentive Stock Plan	1,248		1,248
Purchase and cancellation of common stock	(11,448)	$ (1)	(244)	(11,203)
Purchase and cancellation of common stock, Shares		(135,787)
Cancellation of non-vested stock, net of issuances	(1)	$ (1)
Cancellation of non-vested stock, net of issuances, shares		(2,937)
Other stock-related activity, net of tax	175		483	(308)
Other stock related activity, net of tax, Shares		111
Net income	34,259			34,259
Ending Balance at Sep. 26, 2020	831,365	$ 324	56,893	774,148
Ending Balance, Shares at Sep. 26, 2020		32,304,686
Beginning Balance at Dec. 26, 2020	$ 853,559	$ 322	64,085	789,152
Beginning Balance, Shares at Dec. 26, 2020	32,168,740	32,168,740
Exercise of stock options	$ 909		909
Exercise of stock options, shares		19,606
Compensation expense under Incentive Stock Plan	6,212		6,212
Purchase and cancellation of common stock	(54,613)	$ (5)	(970)	(53,638)
Purchase and cancellation of common stock, Shares		(539,075)
Issuance of non-vested stock, net of cancellations	2,493		2,493
Issuance of non-vested stock, net of cancellations, Shares		19,984
Other stock-related activity, net of tax	(1,488)		596	(2,084)
Other stock related activity, net of tax, Shares		(10,552)
Net income	97,452			97,452
Ending Balance at Sep. 25, 2021	$ 904,524	$ 317	73,325	830,882
Ending Balance, Shares at Sep. 25, 2021	31,658,703	31,658,703
Beginning Balance at Jun. 26, 2021	$ 892,985	$ 319	71,947	820,719
Beginning Balance, Shares at Jun. 26, 2021		31,891,890
Exercise of stock options	173		173
Exercise of stock options, shares		2,260
Compensation expense under Incentive Stock Plan	1,721		1,721
Purchase and cancellation of common stock	(23,364)	$ (2)	(421)	(22,941)
Purchase and cancellation of common stock, Shares		(234,044)
Cancellation of non-vested stock, net of issuances, shares		(537)
Other stock-related activity, net of tax	(95)		(95)
Other stock related activity, net of tax, Shares		(866)
Net income	33,104			33,104
Ending Balance at Sep. 25, 2021	$ 904,524	$ 317	$ 73,325	$ 830,882
Ending Balance, Shares at Sep. 25, 2021	31,658,703	31,658,703