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. 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		34,780			34,780
Other comprehensive income (loss), net of reclassification adjustments and tax			1,075		1,075
Dividends paid		(16,677)			(16,677)
Balance, at Jun. 29, 2019	$ 9,949	1,181,647	1,337	$ (150,857)	1,042,076
Balance, shares at Jun. 29, 2019	33,047,807			6,149,364
Balance, at Mar. 30, 2019	$ 9,949	1,169,510	883	$ (150,857)	1,029,485
Balance, shares at Mar. 30, 2019	33,047,807			6,149,364
Net income		20,475			20,475
Other comprehensive income (loss), net of reclassification adjustments and tax			454		454
Dividends paid		(8,339)			(8,339)
Balance, at Jun. 29, 2019	$ 9,949	1,181,647	1,337	$ (150,857)	1,042,076
Balance, shares at Jun. 29, 2019	33,047,807			6,149,364
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		68,161			68,161
Other comprehensive income (loss), 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
Net income		41,472			41,472
Other comprehensive income (loss), 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