EXCESS MORTGAGE SERVICING RIGHTS - Summary of Direct Investments in Excess MSRs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Weighted Average Life (Years)	1 year 3 months 18 days
Servicer Advance Investments | Servicer Advances
Schedule of Equity Method Investments [Line Items]
Residential mortgage loan UPB and other collateral	$ 19,171,537		$ 20,314,977
Original and Recaptured Pools
Schedule of Equity Method Investments [Line Items]
Original and Recaptured Pools	(2,630)	$ (4,618)
Excess MSRs
Schedule of Equity Method Investments [Line Items]
Residential mortgage loan UPB and other collateral	$ 54,617,600
Weighted Average Life (Years)	6 years 8 months 12 days
Amortized Cost Basis	$ 215,058
Carrying Value	257,388		259,198
Excess MSRs | Agency | Original and Recaptured Pools
Schedule of Equity Method Investments [Line Items]
Residential mortgage loan UPB and other collateral	$ 25,430,543
Weighted Average Life (Years)	6 years 3 months 18 days
Amortized Cost Basis	$ 119,311
Carrying Value	$ 129,667		131,997
Excess MSRs | Agency | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	32.50%
Excess MSRs | Agency | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	66.70%
Excess MSRs | Agency | Original and Recaptured Pools | Weighted Average
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	53.30%
Excess MSRs | Agency | Fortress-managed funds | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	0.00%
Excess MSRs | Agency | Fortress-managed funds | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	40.00%
Excess MSRs | Agency | Mr. Cooper | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	20.00%
Excess MSRs | Agency | Mr. Cooper | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	35.00%
Excess MSRs | Non-Agency | Original and Recaptured Pools
Schedule of Equity Method Investments [Line Items]
Residential mortgage loan UPB and other collateral	$ 29,187,057
Weighted Average Life (Years)	7 years 1 month 6 days
Amortized Cost Basis	$ 95,747
Carrying Value	$ 127,721		$ 127,201
Excess MSRs | Non-Agency | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	33.30%
Excess MSRs | Non-Agency | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	100.00%
Excess MSRs | Non-Agency | Original and Recaptured Pools | Weighted Average
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	59.40%
Excess MSRs | Non-Agency | Fortress-managed funds | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	0.00%
Excess MSRs | Non-Agency | Fortress-managed funds | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	50.00%
Excess MSRs | Non-Agency | Mr. Cooper | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	0.00%
Excess MSRs | Non-Agency | Mr. Cooper | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	33.30%