Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Balance, at Dec. 30, 2017	$ 9,949	$ 5,481	$ 1,127,872	$ (5,481)	$ 5,880	$ (150,857)	$ 992,844
Balance, shares at Dec. 30, 2017	33,047,807					6,149,364
Net income			62,738				62,738
Other comprehensive income, net of reclassification adjustments and tax					(137)		(137)
Dividends paid			(32,546)				(32,546)
Balance, at Dec. 29, 2018	$ 9,949		1,163,545		262	$ (150,857)	1,022,899
Balance, shares at Dec. 29, 2018	33,047,807					6,149,364
Net income			67,983				67,983
Other comprehensive income, net of reclassification adjustments and tax					1,218		1,218
Dividends paid			(33,354)				(33,354)
Balance, at Dec. 28, 2019	$ 9,949		1,198,173		1,480	$ (150,857)	1,058,745
Balance, shares at Dec. 28, 2019	33,047,807					6,149,364
Net income			118,917				118,917
Other comprehensive income, net of reclassification adjustments and tax					1,806		1,806
Dividends paid			(33,354)				(33,354)
Balance, at Dec. 26, 2020	$ 9,949		$ 1,283,737		$ 3,286	$ (150,857)	$ 1,146,115
Balance, shares at Dec. 26, 2020	33,047,807					6,149,364