THE FREMF TRUSTS - Condensed Consolidated Statements of Operations (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statements of Operations
Interest expense	$ 17,938,000	$ 17,881,000	$ 16,767,000	$ 16,408,000	$ 16,259,000	$ 16,580,000	$ 17,837,000	$ 18,857,000
Net interest income	4,782,000	4,746,000	4,828,000	5,784,000	5,903,000	6,153,000	5,772,000	5,760,000	$ 20,139,551	$ 23,588,344	$ 31,309,716
General and administrative fees									(5,454,786)	(5,867,851)	(6,660,934)
Unrealized gain (loss) on multi-family loans held in securitization trusts									3,353,365	(5,219,530)	6,097,000
Net income (loss)	$ 8,891,000	$ (4,256,000)	$ (2,297,000)	$ 2,369,000	$ 11,538,000	$ 1,496,000	$ (4,076,000)	$ (16,948,000)	4,706,961	(7,989,955)	450,479
FREMF Trusts
Statements of Operations
Interest income									54,271,017	58,587,780	68,016,595
Interest expense									51,440,694	54,940,386	62,157,176
Net interest income									2,830,323	3,647,394	5,859,419
General and administrative fees									(2,551,296)	(2,711,189)	(3,249,208)
Unrealized gain (loss) on multi-family loans held in securitization trusts									3,353,365	(5,219,530)	6,097,000
Net income (loss)									$ 3,632,392	$ (4,283,325)	$ 8,707,211