Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		68,161			68,161
Other comprehensive income, net of reclassification adjustments and tax			1,118		1,118
Dividends paid		(16,677)			(16,677)
Balance, at Jun. 27, 2020	$ 9,949	1,249,657	2,598	$ (150,857)	1,111,347
Balance, shares at Jun. 27, 2020	33,047,807			6,149,364
Balance, at Mar. 28, 2020	$ 9,949	1,216,524	1,569	$ (150,857)	1,077,185
Balance, shares at Mar. 28, 2020	33,047,807			6,149,364
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		41,472			41,472
Other comprehensive income, net of reclassification adjustments and tax			1,029		1,029
Dividends paid		(8,339)			(8,339)
Balance, at Jun. 27, 2020	$ 9,949	1,249,657	2,598	$ (150,857)	1,111,347
Balance, shares at Jun. 27, 2020	33,047,807			6,149,364
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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		57,727			57,727
Other comprehensive income, net of reclassification adjustments and tax			(580)		(580)
Dividends paid		(16,677)			(16,677)
Balance, at Jun. 26, 2021	$ 9,949	1,324,787	2,706	$ (150,857)	1,186,585
Balance, shares at Jun. 26, 2021	33,047,807			6,149,364
Balance, at Mar. 27, 2021	$ 9,949	1,299,653	2,512	$ (150,857)	1,161,257
Balance, shares at Mar. 27, 2021	33,047,807			6,149,364
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		33,472			33,472
Other comprehensive income, net of reclassification adjustments and tax			195		195
Dividends paid		(8,339)			(8,339)
Balance, at Jun. 26, 2021	$ 9,949	$ 1,324,787	$ 2,706	$ (150,857)	$ 1,186,585
Balance, shares at Jun. 26, 2021	33,047,807			6,149,364