Interim Financial Information (Schedule Of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2015	Oct. 04, 2015	Jul. 05, 2015	Apr. 05, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interim Financial Information [Abstract]
Net Sales	$ 131,914	$ 74,533	$ 69,516	$ 65,942	$ 115,744	$ 72,325	$ 84,609	$ 82,971	$ 341,905	$ 355,649	$ 347,198
Gross Profit	35,353	17,094	17,167	16,048	29,659	18,605	20,560	20,609	85,662	89,433	81,306
Earnings from continuing operations	19,702	7,767	7,936	6,510	16,070	8,157	9,636	8,299	41,915	42,162	30,752
Earnings (loss) from discontinued operations, net of tax	1,073	537	338	701	(914)	(46)	(516)	(190)	2,649	(1,666)	(4,275)
Net earnings	$ 20,775	$ 8,304	$ 8,274	$ 7,211	$ 15,156	$ 8,111	$ 9,120	$ 8,109	$ 44,564	$ 40,496	$ 26,477
Earnings from continuing operations per share, basic and diluted	$ 2.82	$ 1.11	$ 1.14	$ 0.94	$ 2.31	$ 1.18	$ 1.38	$ 1.20	$ 6.01	$ 6.07	$ 4.44
Earnings (loss) from discontinued operations per share, net of tax, basic and diluted	0.15	0.08	0.05	0.10	(0.13)	(0.01)	(0.07)	(0.03)	0.38	(0.24)	(0.62)
Net earnings per share	$ 2.97	$ 1.19	$ 1.19	$ 1.04	$ 2.18	$ 1.17	$ 1.31	$ 1.17	$ 6.39	$ 5.83	$ 3.82