Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2016	$ 601,642	$ 345	$ 44,187	$ 557,110
Beginning Balance, Shares at Dec. 31, 2016		34,517,633
Exercise of stock options	31		31
Exercise of stock options, shares		29,750
Compensation expense under Incentive Stock Plan	3,162		3,162
Purchase and cancellation of common stock	$ (76,129)	$ (10)	(1,848)	(74,271)
Purchase and cancellation of common stock, Shares	(19,110)	(1,025,475)
Issuance of non-vested stock, net of cancellations	$ 675	$ 1	674
Issuance of non-vested stock, net of cancellations, Shares		65,317
Other stock related activity, net of tax	(1,173)		(1,394)	221
Other stock related activity, net of tax, Shares		(15,701)
Net income	106,599			106,599
Ending Balance at Dec. 30, 2017	634,807	$ 336	44,812	589,659
Ending 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	(26,280)	(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	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	(22,380)	(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