Segment Information - Financial Data by Segment (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Net sales	$ 24,666,000	$ 30,008,000	$ 33,396,000	$ 19,152,000	$ 21,379,000	$ 22,135,000	$ 28,412,000	$ 17,651,000	$ 107,222,306	$ 89,576,777
Operating income									7,394,461	5,879,096
Assets	79,308,086				68,078,979				79,308,086	68,078,979
Additions to property, plant and equipment									2,042,000	4,592,000
Depreciation and amortization									1,700,000	1,205,000
United States
Net sales									91,298,000	73,608,000
Operating income									6,760,000	5,082,000
Assets	70,525,000				57,068,000				70,525,000	57,068,000
Additions to property, plant and equipment									2,011,000	4,500,000
Depreciation and amortization									1,618,000	1,116,000
Canada
Net sales									8,841,000	8,092,000
Operating income									625,000	557,000
Assets	4,363,000				5,329,000				4,363,000	5,329,000
Additions to property, plant and equipment									12,000	47,000
Depreciation and amortization									7,000	9,000
Europe
Net sales									7,083,000	7,877,000
Operating income									9,000	240,000
Assets	4,419,000				5,682,000				4,419,000	5,682,000
Additions to property, plant and equipment									19,000	45,000
Depreciation and amortization									$ 75,000	$ 80,000