Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Cumulative effect of accounting principle adoption of ASU 2016-01		$ 5,482	$ (5,482)
Balance, at Dec. 30, 2017	$ 9,949	1,127,872	5,880	$ (150,857)	$ 992,844
Balance, shares at Dec. 30, 2017	33,047,807			6,149,364
Net income		49,492			49,492
Other comprehensive income (loss), net of reclassification adjustments and tax			(581)		(581)
Dividends paid		(24,209)			(24,209)
Balance, at Sep. 29, 2018	$ 9,949	1,158,636	(184)	$ (150,857)	1,017,545
Balance, shares at Sep. 29, 2018	33,047,807			6,149,364
Balance, at Jun. 30, 2018	$ 9,949	1,152,499	(8)	$ (150,857)	1,011,583
Balance, shares at Jun. 30, 2018	33,047,807			6,149,364
Net income		14,207			14,207
Other comprehensive income (loss), net of reclassification adjustments and tax			(175)		(175)
Dividends paid		(8,069)			(8,069)
Balance, at Sep. 29, 2018	$ 9,949	1,158,636	(184)	$ (150,857)	1,017,545
Balance, shares at Sep. 29, 2018	33,047,807			6,149,364
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		49,098			49,098
Other comprehensive income (loss), net of reclassification adjustments and tax			1,203		1,203
Dividends paid		(25,016)			(25,016)
Balance, at Sep. 28, 2019	$ 9,949	1,187,627	1,465	$ (150,857)	1,048,184
Balance, shares at Sep. 28, 2019	33,047,807			6,149,364
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
Net income		14,319			14,319
Other comprehensive income (loss), net of reclassification adjustments and tax			127		127
Dividends paid		(8,339)			(8,339)
Balance, at Sep. 28, 2019	$ 9,949	$ 1,187,627	$ 1,465	$ (150,857)	$ 1,048,184
Balance, shares at Sep. 28, 2019	33,047,807			6,149,364