EXCESS MORTGAGE SERVICING RIGHTS - Summary of Direct Investments in Excess MSRs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 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	$ 18,224,076		$ 18,224,076		$ 20,314,977
Original and Recaptured Pools
Schedule of Equity Method Investments [Line Items]
Original and Recaptured Pools	1,066	$ (4,211)	(1,564)	$ (8,829)
Excess MSRs
Schedule of Equity Method Investments [Line Items]
Residential mortgage loan UPB and other collateral	52,183,103		$ 52,183,103
Weighted Average Life (Years)			6 years 9 months 18 days
Amortized Cost Basis	212,819		$ 212,819
Carrying Value	256,216		256,216		259,198
Excess MSRs | Agency | Original and Recaptured Pools
Schedule of Equity Method Investments [Line Items]
Residential mortgage loan UPB and other collateral	24,304,488		$ 24,304,488
Weighted Average Life (Years)			6 years 4 months 24 days
Amortized Cost Basis	117,834		$ 117,834
Carrying Value	$ 128,793		$ 128,793		131,997
Excess MSRs | Agency | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	32.50%		32.50%
Excess MSRs | Agency | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	66.70%		66.70%
Excess MSRs | Agency | Original and Recaptured Pools | Weighted Average
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	53.30%		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%		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%		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%		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%		35.00%
Excess MSRs | Non-Agency | Original and Recaptured Pools
Schedule of Equity Method Investments [Line Items]
Residential mortgage loan UPB and other collateral	$ 27,878,615		$ 27,878,615
Weighted Average Life (Years)			7 years 3 months 18 days
Amortized Cost Basis	94,985		$ 94,985
Carrying Value	$ 127,423		$ 127,423		$ 127,201
Excess MSRs | Non-Agency | Original and Recaptured Pools | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	33.30%		33.30%
Excess MSRs | Non-Agency | Original and Recaptured Pools | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	100.00%		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%		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%		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%		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%		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%		33.30%