Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidated Statements Of Comprehensive Income [Abstract]
Net sales	$ 427,690,000	$ 412,363,000	$ 420,188,000
Cost of sales	338,113,000	335,162,000	340,836,000
Gross profit	89,577,000	77,201,000	79,352,000
Selling and general expenses	24,010,000	23,216,000	21,231,000
Intangibles amortization	5,173,000	11,991,000	667,000
Impairment of finite lived intangible assets		2,063,000
Goodwill impairment	0	0	2,840,000
Change in contingent consideration liability			(3,000,000)
Operating profit	60,394,000	39,931,000	57,614,000
Other income, principally interest	396,000	366,000	731,000
Earnings before provision for income taxes	60,790,000	40,297,000	58,345,000
Provision for income taxes	20,294,000	13,820,000	17,093,000
Net earnings	$ 40,496,000	$ 26,477,000	$ 41,252,000
Weighted average common shares outstanding:
Basic and diluted	6,951	6,930	6,907
Net earnings per share:
Basic and diluted	$ 5.83	$ 3.82	$ 5.97
Other comprehensive loss, net of tax:
Unrealized loss on available-for-sale securities	$ 6,000	$ 11,000	$ 45,000
Comprehensive income	$ 40,490,000	$ 26,466,000	$ 41,207,000