Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Consolidated Statements Of Comprehensive Income [Abstract]
Net sales	$ 63,850,000	$ 76,826,000
Cost of sales	51,358,000	56,549,000
Gross profit	12,492,000	20,277,000
Selling and general expenses	6,444,000	6,151,000
Intangibles amortization		745,000
Operating profit	6,048,000	13,381,000
Other income	1,632,000	895,000
Earnings from continuing operations before provision for income taxes	7,680,000	14,276,000
Provision for income taxes from continuing operations	1,729,000	3,282,000
Earnings from continuing operations	5,951,000	10,994,000
Loss from discontinued operations, net of tax		8,000
Net earnings	$ 5,951,000	$ 10,986,000
Weighted average common shares outstanding:
Basic and diluted	7,014	6,999
Earnings per share, basic and diluted:
From continuing operations	$ 0.85	$ 1.57
From discontinued operations	0.00	0.00
Net earnings per share	$ 0.85	$ 1.57
Other comprehensive income, net of tax:
Unrealized gain on available-for-sale securities	$ 69,000	$ 44,000
Comprehensive income	$ 6,020,000	$ 11,030,000
Cash dividends declared and paid per common share	$ 6.00	$ 6.00