AVAILABLE-FOR-SALE SECURITIES - AFS Securities by Collateral Type (Details) - USD ($)		Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	[1]	$ 1,290,825,648	$ 870,929,601
Agency
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		1,285,083,648	790,190,233
Agency | Federal Home Loan Mortgage Corporation
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		530,640,091	326,958,046
Agency | Federal National Mortgage Association
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		754,443,557	463,232,187
Non-Agency
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		0	7,592,802
Multi-Family
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		$ 5,742,000	$ 73,146,566

[1] Our consolidated balance sheets include assets and liabilities of consolidated variable interest entities (“VIE's) as the Company is the primary beneficiary of these VIEs. As of December 31, 2017 and December 31, 2016, assets of consolidated VIEs totaled $1,255,404,335 and $1,369,120,941, respectively, and the liabilities of consolidated VIEs totaled $1,228,295,517 and $1,344,404,080, respectively