Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Consolidated Statements Of Comprehensive Income [Abstract]
Net sales	$ 70,614	$ 74,533	$ 218,029	$ 209,991
Cost of sales	51,722	57,439	161,451	159,682
Gross profit	18,892	17,094	56,578	50,309
Selling and general expenses	5,729	5,666	16,907	17,107
Intangibles amortization	1,479		1,851	568
Operating profit	11,684	11,428	37,820	32,634
Other income	792	225	2,722	596
Earnings from continuing operations before provision for income taxes	12,476	11,653	40,542	33,230
Provision for income taxes from continuing operations	4,138	3,886	13,290	11,017
Earnings from continuing operations	8,338	7,767	27,252	22,213
Earnings (loss) from discontinued operations, net of tax	(6)	537	8,947	1,576
Net earnings	$ 8,332	$ 8,304	$ 36,199	$ 23,789
Weighted average shares outstanding:
Basic and diluted	6,991	6,972	6,987	6,969
Earnings per share, basic and diluted:
From continuing operations	$ 1.19	$ 1.11	$ 3.90	$ 3.18
From discontinued operations	0.00	0.08	1.28	0.23
Net earnings per share	$ 1.19	$ 1.19	$ 5.18	$ 3.41
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities	$ 12	$ (29)	$ 35	$ (11)
Comprehensive income	$ 8,344	$ 8,275	$ 36,234	$ 23,778
Cash dividends declared and paid per common share	$ 0.00	$ 0.00	$ 5.50	$ 5.05