CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Revenue	$ 22,280,964	$ 21,944,320	$ 34,950,997	$ 41,820,886
Cost of sales	17,246,963	18,095,951	41,556,100	34,370,446
Gross profit (loss)	5,034,001	3,848,369	(6,605,103)	7,450,440
Selling, general and administrative expenses	1,868,787	2,049,793	4,589,170	4,069,159
Income (loss) from operations	3,165,214	1,798,576	(11,194,273)	3,381,281
Interest expense	323,634	270,468	599,367	485,053
Income (loss) before provision for (benefit from) income taxes	2,841,580	1,528,108	(11,793,640)	2,896,228
Provision for (benefit from) income taxes	1,051,000	538,000	(4,364,000)	978,000
Net income (loss)	1,790,580	990,108	(7,429,640)	1,918,228
Other comprehensive income (loss) net of tax
Change in unrealized loss - interest rate swap	(73,936)	1,637	(70,483)	2,644
Comprehensive income (loss)	$ 1,716,644	$ 991,745	$ (7,500,123)	$ 1,920,872
Income (loss) per common share - basic (in dollars per share)	$ 0.21	$ 0.12	$ (0.86)	$ 0.22
Income (loss) per common share - diluted (in dollars per share)	$ 0.21	$ 0.12	$ (0.86)	$ 0.22
Shares used in computing income (loss) per common share:
Basic (shares)	8,610,453	8,551,578	8,603,495	8,534,395
Diluted (shares)	8,637,393	8,609,693	8,603,495	8,595,848