Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 29, 2018	$ 727,623	$ 330	$ 47,861	$ 679,432
Beginning Balance, Shares at Dec. 29, 2018		33,004,861
Exercise of stock options	31		31
Exercise of stock options, shares		11,910
Compensation expense under Incentive Stock Plan	2,047		2,047
Purchase and cancellation of common stock	(24,339)	$ (3)	(522)	(23,814)
Purchase and cancellation of common stock, Shares		(290,274)
Issuance of non-vested stock, net of cancellations	868	$ 1	867
Issuance of non-vested stock, net of cancellations, Shares		64,292
Other stock related activity, net of tax	(803)		1,230	(2,033)
Other stock related activity, net of tax, Shares		(9,458)
Net income	44,905			44,905
Ending Balance at Jun. 29, 2019	750,332	$ 328	51,514	698,490
Ending Balance, Shares at Jun. 29, 2019		32,781,331
Beginning Balance at Dec. 29, 2018	$ 727,623	$ 330	47,861	679,432
Beginning Balance, Shares at Dec. 29, 2018		33,004,861
Purchase and cancellation of common stock, Shares	(22,380)
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
Beginning Balance at Mar. 30, 2019	$ 741,707	$ 329	49,890	691,488
Beginning Balance, Shares at Mar. 30, 2019		32,942,013
Exercise of stock options, shares		196
Compensation expense under Incentive Stock Plan	1,132		1,132
Purchase and cancellation of common stock	(14,704)	$ (2)	(315)	(14,387)
Purchase and cancellation of common stock, Shares		(175,184)
Issuance of non-vested stock, net of cancellations	868	$ 1	867
Issuance of non-vested stock, net of cancellations, Shares		16,099
Other stock related activity, net of tax	(170)		(60)	(110)
Other stock related activity, net of tax, Shares		(1,793)
Net income	21,499			21,499
Ending Balance at Jun. 29, 2019	750,332	$ 328	51,514	698,490
Ending Balance, Shares at Jun. 29, 2019		32,781,331
Beginning Balance at Dec. 28, 2019	$ 773,584	$ 326	52,605	720,653
Beginning Balance, Shares at Dec. 28, 2019	32,558,168	32,556,263
Exercise of stock options, shares		10
Compensation expense under Incentive Stock Plan	$ 2,718		2,718
Purchase and cancellation of common stock	$ (5,865)	$ (1)	(177)	(5,687)
Purchase and cancellation of common stock, Shares	(6,350)	(98,329)
Issuance of non-vested stock, net of cancellations	$ 505	$ 1	504
Issuance of non-vested stock, net of cancellations, Shares		(11,845)
Other stock related activity, net of tax	(470)		(244)	(226)
Other stock related activity, net of tax, Shares		(5,686)
Net income	36,660			36,660
Ending Balance at Jun. 27, 2020	807,132	$ 326	55,406	751,400
Ending Balance, Shares at Jun. 27, 2020		32,440,413
Beginning Balance at Mar. 28, 2020	$ 791,375	$ 325	53,454	737,596
Beginning Balance, Shares at Mar. 28, 2020	32,440,413	32,434,665
Compensation expense under Incentive Stock Plan	$ 1,504		1,504
Purchase and cancellation of common stock	(86)	$ (1)	(2)	(83)
Purchase and cancellation of common stock, Shares		(1,620)
Issuance of non-vested stock, net of cancellations	506	$ 2	504
Issuance of non-vested stock, net of cancellations, Shares		10,129
Other stock related activity, net of tax	(52)		(54)	2
Other stock related activity, net of tax, Shares		(2,761)
Net income	13,885			13,885
Ending Balance at Jun. 27, 2020	$ 807,132	$ 326	$ 55,406	$ 751,400
Ending Balance, Shares at Jun. 27, 2020		32,440,413