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
Provision for stock-based compensation	1,998		1,998
Purchase and cancellation of common stock	(28,066)	$ (4)	(738)	(27,324)
Purchase and cancellation of common stock, Shares		(409,888)
Issuance of non-vested stock, net of cancellations	1,022		1,022
Issuance of non-vested stock, net of cancellations, Shares		73,823
Other stock related activity, net of tax	(730)		(729)	(1)
Other stock related activity, net of tax, Shares		(9,688)
Net income	64,985			64,985
Ending Balance at Jun. 30, 2018	674,016	$ 332	46,365	627,319
Ending Balance, Shares at Jun. 30, 2018		33,225,771
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 Mar. 31, 2018	$ 657,138	$ 335	45,466	611,337
Beginning Balance, Shares at Mar. 31, 2018		33,503,499
Provision for stock-based compensation	1,100		1,100
Purchase and cancellation of common stock	(18,858)	$ (2)	(501)	(18,355)
Purchase and cancellation of common stock, Shares		(278,138)
Issuance of non-vested stock, net of cancellations	414	$ (1)	415
Issuance of non-vested stock, net of cancellations, Shares		7,382
Other stock related activity, net of tax	(117)		(115)	(2)
Other stock related activity, net of tax, Shares		(6,972)
Net income	34,339			34,339
Ending Balance at Jun. 30, 2018	674,016	$ 332	46,365	627,319
Ending Balance, Shares at Jun. 30, 2018		33,225,771
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		11,910
Provision for stock-based compensation	2,047		2,047
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		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	32,781,331
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
Provision for stock-based compensation	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	32,781,331