Industry Segments - Financial Information Related to Geographic Area (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
Net sales
Consolidated 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
Long-lived assets
Consolidated long-lived assets	18,166,000				8,070,000				18,166,000	8,070,000
United States [Member]
Net sales
Consolidated net sales									141,357,000	143,784,000	144,739,000
Long-lived assets
Consolidated long-lived assets	6,604,000				4,214,000				6,604,000	4,214,000
Foreign [Member]
Net sales
Consolidated net sales									58,505,000	60,633,000	$ 39,919,000
Long-lived assets
Consolidated long-lived assets	$ 11,562,000				$ 3,856,000				$ 11,562,000	$ 3,856,000