CONDENSED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 20,261,239	$ 16,731,951	$ 38,452,862	$ 36,764,652
Cost of revenue	15,676,421	13,048,203	29,818,176	28,543,390
Gross profit	4,584,818	3,683,748	8,634,686	8,221,262
Selling, general and administrative expenses	2,557,759	2,002,198	4,607,599	4,166,076
Income from operations	2,027,059	1,681,550	4,027,087	4,055,186
Interest expense	416,834	465,903	864,097	856,238
Income before provision for income taxes	1,610,225	1,215,647	3,162,990	3,198,948
Provision for income taxes	353,000	450,000	649,000	1,184,000
Net income	1,257,225	765,647	2,513,990	2,014,948
Other comprehensive income (loss), net of tax - change in unrealized (gain) loss on interest rate swap	20,600	(1,000)	14,800	4,200
Comprehensive income	$ 1,277,825	$ 764,647	$ 2,528,790	$ 2,019,148
Income per common share - basic (in dollars per share)	$ 0.14	$ 0.09	$ 0.28	$ 0.23
Income per common share - diluted (in dollars per share)	$ 0.14	$ 0.09	$ 0.28	$ 0.23
Shares used in computing income per common share:
Basic (in shares)	8,938,331	8,832,478	8,913,394	8,806,942
Diluted (in shares)	8,980,155	8,865,055	8,953,321	8,840,309