Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 30, 2017	$ 634,807	$ 336	$ 44,812	$ 589,659
Beginning Balance, Shares at Dec. 30, 2017		33,571,524
Exercise of stock options	200		200
Exercise of stock options, shares		10,572
Compensation expense under Incentive Stock Plan	3,460		3,460
Purchase and cancellation of common stock	(45,351)	$ (7)	(1,167)	(44,177)
Purchase and cancellation of common stock, Shares		(648,503)
Issuance of non-vested stock, net of cancellations	1,799	$ 1	1,798
Issuance of non-vested stock, net of cancellations, Shares		83,891
Other stock related activity, net of tax	(894)		(1,242)	348
Other stock related activity, net of tax, Shares		(12,623)
Net income	133,602			133,602
Ending Balance at Dec. 29, 2018	727,623	$ 330	47,861	679,432
Ending Balance, Shares at Dec. 29, 2018		33,004,861
Exercise of stock options	123		123
Exercise of stock options, shares		14,227
Compensation expense under Incentive Stock Plan	3,077		3,077
Purchase and cancellation of common stock	(41,339)	$ (5)	(939)	(40,395)
Purchase and cancellation of common stock, Shares		(521,944)
Issuance of non-vested stock, net of cancellations	1,377	$ 1	1,376
Issuance of non-vested stock, net of cancellations, Shares		69,826
Other stock related activity, net of tax	(1,039)		1,107	(2,146)
Other stock related activity, net of tax, Shares		(10,707)
Net income	83,762			83,762
Ending Balance at Dec. 28, 2019	$ 773,584	$ 326	52,605	720,653
Ending Balance, Shares at Dec. 28, 2019	32,558,168	32,556,263
Exercise of stock options	$ 1,184		1,184
Exercise of stock options, shares		27,787
Compensation expense under Incentive Stock Plan	7,586		7,586
Purchase and cancellation of common stock	(38,676)	$ (5)	(833)	(37,838)
Purchase and cancellation of common stock, Shares		(462,635)
Issuance of non-vested stock, net of cancellations	3,463	$ 1	3,462
Issuance of non-vested stock, net of cancellations, Shares		53,572
Other stock related activity, net of tax	(452)		81	(533)
Other stock related activity, net of tax, Shares		(6,247)
Net income	106,870			106,870
Ending Balance at Dec. 26, 2020	$ 853,559	$ 322	$ 64,085	$ 789,152
Ending Balance, Shares at Dec. 26, 2020	32,168,740	32,168,740