Consolidated Statements Of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance (in shares) at Dec. 31, 2019	7,006
Balance at Dec. 31, 2019	$ 7,441	$ 11,447	$ 362,842	$ 136	$ (13,909)	$ 367,957
Net earnings			8,222			8,222
Unrealized gain on available-for-sale securities, net of tax				93		93
Dividends paid			(42,172)			(42,172)
Other (in shares)	10
Other		281			309	590
Balance (in shares) at Mar. 29, 2020	7,016
Balance at Mar. 29, 2020	$ 7,441	11,728	328,892	229	(13,600)	334,690
Balance (in shares) at Dec. 31, 2020	7,025
Balance at Dec. 31, 2020	$ 7,441	12,438	367,627	154	(13,312)	374,348
Net earnings			8,993			8,993
Unrealized gain on available-for-sale securities, net of tax				(49)		(49)
Dividends paid			(44,083)			(44,083)
Other (in shares)	11
Other		568			341	910
Balance (in shares) at Apr. 04, 2021	7,036
Balance at Apr. 04, 2021	$ 7,441	$ 13,006	$ 332,538	$ 105	$ (12,971)	$ 340,119