INVESTMENTS IN EXCESS MORTGAGE SERVICING RIGHTS - Summary of Direct Investments in Excess MSRs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Investment [Line Items]
Weighted Average Life (Years)			1 year 3 months 1 day
Carrying Value	$ 1,702,749		$ 1,702,749		$ 659,483
Principal investment gain (loss)	(14,291)	$ (17,060)	(32,650)	$ (24,397)
Servicer Advance Joint Venture | Servicer Advances
Investment [Line Items]
UPB of Underlying Mortgages	145,763,758		145,763,758		186,362,657
Original and Recaptured Pools
Investment [Line Items]
Principal investment gain (loss)	(12,047)	(15,395)	(41,032)	(28,392)
Recapture Agreements
Investment [Line Items]
Principal investment gain (loss)	(2,244)	$ (1,665)	8,382	$ 3,995
Excess MSRs
Investment [Line Items]
UPB of Underlying Mortgages	228,173,728		$ 228,173,728
Weighted Average Life (Years)			6 years
Amortized Cost Basis	1,070,091		$ 1,070,091
Carrying Value	1,178,308		1,178,308		1,399,455
Excess MSRs | Nationstar
Investment [Line Items]
Carrying Value	541,834		541,834		611,293
Excess MSRs | Agency
Investment [Line Items]
UPB of Underlying Mortgages	68,449,802		$ 68,449,802
Weighted Average Life (Years)			6 years 3 months 18 days
Amortized Cost Basis	283,673		$ 283,673
Carrying Value	333,849		333,849		381,757
Excess MSRs | Agency | Original and Recaptured Pools
Investment [Line Items]
UPB of Underlying Mortgages	68,449,802		$ 68,449,802
Weighted Average Life (Years)			5 years 9 months 18 days
Amortized Cost Basis	263,374		$ 263,374
Carrying Value	$ 288,345		$ 288,345		330,323
Excess MSRs | Agency | Original and Recaptured Pools | Minimum
Investment [Line Items]
Interest in Excess MSR	32.50%		32.50%
Excess MSRs | Agency | Original and Recaptured Pools | Maximum
Investment [Line Items]
Interest in Excess MSR	66.70%		66.70%
Excess MSRs | Agency | Original and Recaptured Pools | Weighted Average
Investment [Line Items]
Interest in Excess MSR	53.30%		53.30%
Excess MSRs | Agency | Recapture Agreements
Investment [Line Items]
UPB of Underlying Mortgages	$ 0		$ 0
Weighted Average Life (Years)			12 years 7 months 6 days
Amortized Cost Basis	20,299		$ 20,299
Carrying Value	$ 45,504		$ 45,504		51,434
Excess MSRs | Agency | Recapture Agreements | Minimum
Investment [Line Items]
Interest in Excess MSR	32.50%		32.50%
Excess MSRs | Agency | Recapture Agreements | Maximum
Investment [Line Items]
Interest in Excess MSR	66.70%		66.70%
Excess MSRs | Agency | Recapture Agreements | Weighted Average
Investment [Line Items]
Interest in Excess MSR	53.30%		53.30%
Excess MSRs | Agency | Fortress-managed funds | Original and Recaptured Pools | Minimum
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Agency | Fortress-managed funds | Original and Recaptured Pools | Maximum
Investment [Line Items]
Interest in Excess MSR	40.00%		40.00%
Excess MSRs | Agency | Fortress-managed funds | Recapture Agreements | Minimum
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Agency | Fortress-managed funds | Recapture Agreements | Maximum
Investment [Line Items]
Interest in Excess MSR	40.00%		40.00%
Excess MSRs | Agency | Nationstar | Original and Recaptured Pools | Minimum
Investment [Line Items]
Interest in Excess MSR	20.00%		20.00%
Excess MSRs | Agency | Nationstar | Original and Recaptured Pools | Maximum
Investment [Line Items]
Interest in Excess MSR	35.00%		35.00%
Excess MSRs | Agency | Nationstar | Recapture Agreements | Minimum
Investment [Line Items]
Interest in Excess MSR	20.00%		20.00%
Excess MSRs | Agency | Nationstar | Recapture Agreements | Maximum
Investment [Line Items]
Interest in Excess MSR	35.00%		35.00%
Excess MSRs | Non-Agency
Investment [Line Items]
UPB of Underlying Mortgages	$ 159,723,926		$ 159,723,926
Weighted Average Life (Years)			5 years 10 months 24 days
Amortized Cost Basis	786,418		$ 786,418
Carrying Value	844,459		844,459		1,017,698
Excess MSRs | Non-Agency | Original and Recaptured Pools
Investment [Line Items]
UPB of Underlying Mortgages	67,453,347		$ 67,453,347
Weighted Average Life (Years)			5 years 3 months 18 days
Amortized Cost Basis	160,665		$ 160,665
Carrying Value	$ 191,270		$ 191,270		219,980
Excess MSRs | Non-Agency | Original and Recaptured Pools | Minimum
Investment [Line Items]
Interest in Excess MSR	33.30%		33.30%
Excess MSRs | Non-Agency | Original and Recaptured Pools | Maximum
Investment [Line Items]
Interest in Excess MSR	100.00%		100.00%
Excess MSRs | Non-Agency | Original and Recaptured Pools | Weighted Average
Investment [Line Items]
Interest in Excess MSR	59.40%		59.40%
Excess MSRs | Non-Agency | Recapture Agreements
Investment [Line Items]
UPB of Underlying Mortgages	$ 0		$ 0
Weighted Average Life (Years)			12 years 6 months
Amortized Cost Basis	8,352		$ 8,352
Carrying Value	$ 19,561		$ 19,561		13,491
Excess MSRs | Non-Agency | Recapture Agreements | Minimum
Investment [Line Items]
Interest in Excess MSR	33.30%		33.30%
Excess MSRs | Non-Agency | Recapture Agreements | Maximum
Investment [Line Items]
Interest in Excess MSR	100.00%		100.00%
Excess MSRs | Non-Agency | Recapture Agreements | Weighted Average
Investment [Line Items]
Interest in Excess MSR	59.40%		59.40%
Excess MSRs | Non-Agency | Ocwen Serviced Pools
Investment [Line Items]
UPB of Underlying Mortgages	$ 92,270,579		$ 92,270,579
Interest in Excess MSR	100.00%		100.00%
Weighted Average Life (Years)			6 years
Amortized Cost Basis	$ 617,401		$ 617,401
Carrying Value	$ 633,628		$ 633,628		$ 784,227
Excess MSRs | Non-Agency | Fortress-managed funds | Original and Recaptured Pools | Minimum
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Non-Agency | Fortress-managed funds | Original and Recaptured Pools | Maximum
Investment [Line Items]
Interest in Excess MSR	50.00%		50.00%
Excess MSRs | Non-Agency | Fortress-managed funds | Recapture Agreements | Minimum
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Non-Agency | Fortress-managed funds | Recapture Agreements | Maximum
Investment [Line Items]
Interest in Excess MSR	50.00%		50.00%
Excess MSRs | Non-Agency | Fortress-managed funds | Ocwen Serviced Pools
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Non-Agency | Nationstar | Original and Recaptured Pools | Minimum
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Non-Agency | Nationstar | Original and Recaptured Pools | Maximum
Investment [Line Items]
Interest in Excess MSR	33.30%		33.30%
Excess MSRs | Non-Agency | Nationstar | Recapture Agreements | Minimum
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Non-Agency | Nationstar | Recapture Agreements | Maximum
Investment [Line Items]
Interest in Excess MSR	33.30%		33.30%
Excess MSRs | Non-Agency | Nationstar | Ocwen Serviced Pools
Investment [Line Items]
Interest in Excess MSR	0.00%		0.00%