Segment Information - Financial Data by Segment (Details) - 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
Net sales	$ 23,118,000	$ 29,903,000	$ 33,954,000	$ 22,837,000	$ 24,666,000	$ 30,008,000	$ 33,396,000	$ 19,152,000	$ 109,811,768	$ 107,222,306
Operating income									7,347,006	7,394,461
Assets	81,421,366				79,308,086				81,421,366	79,308,086
Additions to property, plant and equipment									1,757,000	2,042,000
Depreciation and amortization									2,053,000	1,700,000
United States
Net sales									96,622,000	91,298,000
Operating income									7,147,000	6,760,000
Assets	73,688,000				70,525,000				73,688,000	70,525,000
Additions to property, plant and equipment									1,720,000	2,011,000
Depreciation and amortization									2,017,000	1,618,000
Canada
Net sales									6,804,000	8,841,000
Operating income									56,000	625,000
Assets	3,709,000				4,363,000				3,709,000	4,363,000
Additions to property, plant and equipment									19,000	12,000
Depreciation and amortization									8,000	7,000
Europe
Net sales									6,385,000	7,083,000
Operating income									144,000	9,000
Assets	$ 4,024,000				$ 4,419,000				4,024,000	4,419,000
Additions to property, plant and equipment									17,000	19,000
Depreciation and amortization									$ 28,000	$ 75,000