AVAILABLE-FOR-SALE SECURITIES - Fair Value of AFS Investment Securities by Rate Type (Details) - USD ($)		Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	[1]	$ 1,095,189,264	$ 1,290,825,648
Adjustable rate
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		1,094,378,500	1,284,237,670
Fixed rate
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		810,764	6,587,978
Agency
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		1,095,189,264	1,285,083,648
Agency | Adjustable rate
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		1,094,378,500	1,284,237,670
Agency | Fixed rate
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		810,764	845,978
Multi-Family
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		0	5,742,000
Multi-Family | Adjustable rate
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		0	0
Multi-Family | Fixed rate
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		$ 0	$ 5,742,000

[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 March 31, 2018 and December 31, 2017, assets of consolidated VIEs totaled $1,223,232,702 and $1,255,404,335 respectively, and the liabilities of consolidated VIEs totaled $1,197,735,060 and $1,228,295,517 respectively