SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($)		Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Cash and cash equivalents	[1]	$ 41,424,138	$ 27,534,374
Restricted cash	[1]	15,816,577	10,355,222
Total cash, cash equivalents and restricted cash		$ 57,240,715	$ 37,889,596	$ 39,990,866	$ 34,315,356

[1] Our consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs") as the Company is the primary beneficiary of these VIEs. As of June 30, 2017 and December 31, 2016, assets of consolidated VIEs totaled $1,308,989,628 and $1,369,120,941 respectively, and the liabilities of consolidated VIEs totaled $1,282,788,661 and $1,344,404,080 respectively