Quarterly Results of Operations (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Summary of the Company's unaudited quarterly results of operations
Revenues	$ 11,041,382	$ 13,649,692	$ 10,436,910	$ 13,404,333	$ 12,409,227	$ 11,688,417	$ 10,977,459	$ 9,901,548	$ 48,532,317	$ 44,976,651	$ 51,938,416
Income (loss) before provision for income taxes	496,621	4,681,299	1,205,966	4,261,110	3,720,381	3,691,429	2,271,253	2,002,849	10,644,996	11,685,912	16,320,690
Net income (loss)	$ 182,621	$ 3,100,299	$ 675,966	$ 3,412,110	$ 2,644,381	$ 2,650,429	$ 1,772,253	$ 1,426,849	$ 7,370,996	$ 8,493,912	$ 11,419,690
Earnings (loss) per share	$ 0.02	$ 0.37	$ 0.08	$ 0.41	$ 0.31	$ 0.32	$ 0.21	$ 0.17	$ 0.88	$ 1.01	$ 1.36