CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (Unaudited)) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenue	$ 20,706,460	$ 22,110,829	$ 57,471,112	$ 57,061,826
Cost of sales	15,794,024	17,086,461	44,337,414	58,642,561
Gross profit (loss)	4,912,436	5,024,368	13,133,698	(1,580,735)
Selling, general and administrative expenses	2,044,304	2,014,147	6,210,380	6,603,321
Income (loss) from operations	2,868,132	3,010,221	6,923,318	(8,184,056)
Interest expense	402,619	338,156	1,258,857	937,523
Income (loss) before provision for (benefit from) income taxes	2,465,513	2,672,065	5,664,461	(9,121,579)
Provision for (benefit from) income taxes	770,000	986,000	1,954,000	(3,378,000)
Net income (loss)	1,695,513	1,686,065	3,710,461	(5,743,579)
Other comprehensive income (loss) net of tax - Change in unrealized gain (loss) interest rate swap	(2,300)	25,936	1,900	(44,547)
Comprehensive income (loss)	$ 1,693,213	$ 1,712,001	$ 3,712,361	$ (5,788,126)
Income (loss) per common share - basic (in dollars per share)	$ 0.19	$ 0.19	$ 0.42	$ (0.67)
Income (loss) per common share - diluted (in dollars per share)	$ 0.19	$ 0.19	$ 0.42	$ (0.67)
Shares used in computing income (loss) per common share:
Basic (shares)	8,846,507	8,678,608	8,820,379	8,628,716
Diluted (shares)	8,872,810	8,692,420	8,841,397	8,628,716