THE FREMF TRUSTS - Narrative (Details) - FREMF Trusts - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Balance Sheet
Investment in Multi-Family MBS, carrying value	$ 21,139,299	$ 18,342,040
Multi-family mortgage loans held in securitization trusts, unpaid principal balance	1,083,704,636	1,147,753,367
Multi-family securitized debt obligations, unpaid principal balance	$ 1,083,704,636	$ 1,147,753,367