Summarized Quarterly Financial Data (Unaudited) (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	Dec. 31, 2013
Summarized Quarterly Financial Data (Unaudited) [Abstract]
Revenues	$ 35,108,810	$ 32,406,877	$ 41,283,142	$ 26,504,344	$ 32,697,113	$ 40,754,205	$ 37,836,265	$ 25,753,864	$ 135,303,173	$ 137,041,447	$ 125,717,630
Gross Profit	5,973,797	6,416,561	10,483,514	4,986,733	5,575,457	6,410,848	6,121,007	4,670,836	27,860,605	22,778,148	23,325,599
Income from Operations	3,665,106	2,601,779	8,649,545	3,280,340	3,589,978	4,929,301	5,131,707	3,761,920	18,196,770	17,412,906	18,843,492
Net income	$ 2,160,289	$ 1,685,897	$ 5,590,530	$ 2,105,489	$ 2,228,015	$ 3,372,944	$ 3,572,107	$ 2,533,294	$ 11,542,205	$ 11,706,360	$ 13,014,648
Net income per share:
Basic	$ 0.11	$ 0.08	$ 0.28	$ 0.10	$ 0.11	$ 0.18	$ 0.19	$ 0.13	$ 0.57	$ 0.61	$ 0.71
Diluted	$ 0.11	$ 0.08	$ 0.28	$ 0.10	$ 0.11	$ 0.18	$ 0.19	$ 0.13	$ 0.57	$ 0.61	$ 0.71

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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