SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)
Net revenues	$ 44,504,140	$ 48,989,479	$ 49,651,094	$ 45,604,637	$ 41,903,782	$ 46,028,226	$ 42,471,150	$ 32,899,260	$ 188,749,350	$ 163,302,418	$ 134,529,379
Operating expenses	40,341,353	40,050,409	39,482,625	38,419,729	39,035,094	39,150,464	39,086,717	30,046,985	158,294,116	147,319,260	124,759,144
Income from operations	4,162,787	8,939,070	10,168,469	7,184,908	2,868,688	6,877,762	3,384,433	2,852,275	30,455,234	15,983,158	9,770,235
Net income	$ 2,059,073	$ 5,519,509	$ 6,120,244	$ 4,261,996	$ 1,339,643	$ 4,137,081	$ 1,792,758	$ 1,641,366	$ 17,960,822	$ 8,910,848	$ 5,675,854
Income per share of common stock
Basic (in dollars per share)	$ 0.12	$ 0.34	$ 0.38	$ 0.26	$ 0.08	$ 0.26	$ 0.11	$ 0.10	$ 1.10	$ 0.55	$ 0.35
Diluted (in dollars per share)	$ 0.12	$ 0.32	$ 0.37	$ 0.26	$ 0.08	$ 0.26	$ 0.11	$ 0.10	$ 1.06	$ 0.55	$ 0.35