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, shares		3,717
Provision for stock-based compensation	3,129		3,129
Purchase and cancellation of common stock	(35,224)	$ (6)	(912)	(34,306)
Purchase and cancellation of common stock, Shares		(506,648)
Issuance of non-vested stock, net of cancellations	1,023	$ 1	1,022
Issuance of non-vested stock, net of cancellations, Shares		82,018
Other stock related activity, net of tax	(785)		(737)	(48)
Other stock related activity, net of tax, Shares		(10,614)
Net income	99,003			99,003
Ending Balance at Sep. 29, 2018	701,953	$ 331	47,314	654,308
Ending Balance, Shares at Sep. 29, 2018		33,139,997
Beginning Balance at Dec. 30, 2017	$ 634,807	$ 336	44,812	589,659
Beginning Balance, Shares at Dec. 30, 2017		33,571,524
Purchase and cancellation of common stock, Shares	(26,280)
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
Beginning Balance at Jun. 30, 2018	$ 674,016	$ 332	46,365	627,319
Beginning Balance, Shares at Jun. 30, 2018		33,225,771
Exercise of stock options, shares		3,717
Provision for stock-based compensation	1,131		1,131
Purchase and cancellation of common stock	(7,158)	$ (2)	(174)	(6,982)
Purchase and cancellation of common stock, Shares		(96,760)
Issuance of non-vested stock, net of cancellations	1	$ 1
Issuance of non-vested stock, net of cancellations, Shares		8,195
Other stock related activity, net of tax	(54)		(8)	(46)
Other stock related activity, net of tax, Shares		(926)
Net income	34,017			34,017
Ending Balance at Sep. 29, 2018	701,953	$ 331	47,314	654,308
Ending Balance, Shares at Sep. 29, 2018		33,139,997
Beginning Balance at Dec. 29, 2018	$ 727,623	$ 330	47,861	679,432
Beginning Balance, Shares at Dec. 29, 2018	33,004,861	33,004,861
Exercise of stock options	$ 31		31
Exercise of stock options, shares		11,995
Provision for stock-based compensation	3,033		3,033
Purchase and cancellation of common stock	$ (24,339)	$ (3)	(522)	(23,814)
Purchase and cancellation of common stock, Shares	(17,710)	(290,274)
Issuance of non-vested stock, net of cancellations	$ 868	$ 1	867
Issuance of non-vested stock, net of cancellations, Shares		70,885
Other stock related activity, net of tax	(837)		1,281	(2,118)
Other stock related activity, net of tax, Shares		(9,914)
Net income	66,213			66,213
Ending Balance at Sep. 28, 2019	$ 772,592	$ 328	52,551	719,713
Ending Balance, Shares at Sep. 28, 2019	32,787,553	32,787,553
Beginning Balance at Jun. 29, 2019	$ 750,332	$ 328	51,514	698,490
Beginning Balance, Shares at Jun. 29, 2019		32,781,331
Exercise of stock options, shares		85
Provision for stock-based compensation	986		986
Issuance of non-vested stock, net of cancellations, Shares		6,593
Other stock related activity, net of tax	(34)		51	(85)
Other stock related activity, net of tax, Shares		(456)
Net income	21,308			21,308
Ending Balance at Sep. 28, 2019	$ 772,592	$ 328	$ 52,551	$ 719,713
Ending Balance, Shares at Sep. 28, 2019	32,787,553	32,787,553