Segment Information - Financial Data by Segment (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Net sales	$ 21,379,000	$ 22,135,000	$ 28,412,000	$ 17,651,000	$ 19,535,000	$ 20,363,000	$ 27,594,000	$ 16,878,000	$ 89,576,777	$ 84,369,770
Operating income									5,879,096	5,360,520
Assets	68,078,979				67,827,816				68,078,979	67,827,816
Additions to property, plant and equipment									4,592,000	681,000
Depreciation and amortization									934,000	1,089,000
United States
Net sales									73,608,000	67,510,000
Operating income									5,082,000	4,394,000
Assets	57,068,000				56,115,000				57,068,000	56,115,000
Additions to property, plant and equipment									4,500,000	656,000
Depreciation and amortization									845,000	980,000
Canada
Net sales									8,092,000	8,808,000
Operating income									557,000	775,000
Assets	5,329,000				6,107,000				5,329,000	6,107,000
Additions to property, plant and equipment									47,000	14,000
Depreciation and amortization									9,000	36,000
Europe
Net sales									7,877,000	8,052,000
Operating income									240,000	192,000
Assets	5,682,000				5,606,000				5,682,000	5,606,000
Additions to property, plant and equipment									45,000	11,000
Depreciation and amortization									$ 80,000	$ 73,000