Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 28, 2013	$ 413,641	$ 365	$ 43,119	$ 370,157
Beginning Balance, Shares at Dec. 28, 2013		36,464,958
Exercise of stock options	463	$ 1	462
Exercise of stock options, shares		66,500
Compensation expense under Incentive Stock Plan	1,146		1,146
Purchase and cancellation of common stock	$ (43,519)	$ (9)	(1,651)	(41,859)
Purchase and cancellation of common stock, Shares	(61,830)	(917,430)
Issuance of non-vested stock, net of cancellations, Shares		5,060
Other stock related activity, net of tax	$ 343	$ (1)	337	7
Other stock related activity, net of tax, Shares		(7,850)
Net income	89,987			89,987
Ending Balance at Dec. 27, 2014	462,061	$ 356	43,413	418,292
Ending Balance, Shares at Dec. 27, 2014		35,611,238
Exercise of stock options	93		93
Exercise of stock options, shares		31,305
Compensation expense under Incentive Stock Plan	882		882
Purchase and cancellation of common stock	$ (37,324)	$ (7)	(1,406)	(35,911)
Purchase and cancellation of common stock, Shares	(33,430)	(781,130)
Issuance of non-vested stock, net of cancellations, Shares		8,922
Other stock related activity, net of tax	$ (5)		(183)	178
Other stock related activity, net of tax, Shares		(6,939)
Net income	92,329			92,329
Ending Balance at Dec. 26, 2015	$ 518,036	$ 349	42,799	474,888
Ending Balance, Shares at Dec. 26, 2015	34,863,396	34,863,396
Compensation expense under Incentive Stock Plan	$ 2,380		2,380
Purchase and cancellation of common stock	$ (24,678)	$ (5)	(846)	(23,827)
Purchase and cancellation of common stock, Shares	(38,970)	(469,836)
Issuance of non-vested stock, net of cancellations		$ 1	(1)
Issuance of non-vested stock, net of cancellations, Shares		131,123
Other stock related activity, net of tax	$ (145)		(145)
Other stock related activity, net of tax, Shares		(7,050)
Net income	106,049			106,049
Ending Balance at Dec. 31, 2016	$ 601,642	$ 345	$ 44,187	$ 557,110
Ending Balance, Shares at Dec. 31, 2016	34,517,633	34,517,633