Discontinued Operations (Summary Of Results) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales	$ 79,227,000	$ 74,561,000	$ 156,053,000	$ 147,415,000
Cost of sales	(59,782,000)	(57,001,000)	(116,331,000)	(109,729,000)
Selling and general expenses	(5,631,000)	(5,418,000)	(11,782,000)	(11,178,000)
Gain on divestiture of business, net	0			11,413,000
Other income	997,000	980,000	1,892,000	1,930,000
Earnings (loss) from discontinued operations, net of tax	(1,000)	771,000	(9,000)	8,953,000
Discontinued Operations Held-for-sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales				421,000
Cost of sales		(17,000)	(11,000)	(485,000)
Selling and general expenses		2,000		(24,000)
Gain on divestiture of business, net	0	709,000		11,413,000
Other income		430,000		2,078,000
Earnings (loss) from discontinued operations before provision for income taxes		1,124,000	(11,000)	13,403,000
Provision for (benefit from) income taxes from discontinued operations	1,000	353,000	(2,000)	4,450,000
Earnings (loss) from discontinued operations, net of tax	$ (1,000)	$ 771,000	$ (9,000)	$ 8,953,000