Selected Quarterly Financial Data (Unaudited) - Selected Quarterly Financial Data (Unaudited) (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 52,784,000	$ 49,675,000	$ 50,719,000	$ 46,684,000	$ 53,277,000	$ 50,725,000	$ 51,669,000	$ 48,746,000	$ 199,862,000	$ 204,417,000	$ 184,658,000
Cost of products sold	34,606,000	33,340,000	33,926,000	31,260,000	37,098,000	34,326,000	34,156,000	33,214,000	133,132,000	138,794,000	126,432,000
Income from continuing operations before income taxes	5,361,000	2,904,000	5,624,000	4,148,000	4,843,000	4,211,000	7,998,000	4,171,000	18,037,000	21,223,000	10,025,000
(Loss) income from discontinued operations, net of tax	(695,000)	(700,000)	(143,000)	(162,000)	4,313,000	400,000	183,000	(181,000)	(1,700,000)	4,715,000	762,000
Net income	$ 3,448,000	$ 1,137,000	$ 3,567,000	$ 2,546,000	$ 7,945,000	$ 2,895,000	$ 5,528,000	$ 2,527,000	$ 10,698,000	$ 18,895,000	$ 8,240,000
Basic net income per common share	$ 0.87	$ 0.29	$ 0.89	$ 0.62	$ 1.92	$ 0.70	$ 1.34	$ 0.61	$ 2.67	$ 4.57	$ 1.99
Diluted net income per common share	$ 0.87	$ 0.29	$ 0.88	$ 0.61	$ 1.89	$ 0.69	$ 1.33	$ 0.61	$ 2.65	$ 4.51	$ 1.97