EXCESS MORTGAGE SERVICING RIGHTS - Summary of Direct Investments in Excess MSRs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Weighted Average Life (Years)			1 year
Agency
Schedule of Equity Method Investments [Line Items]
Original and Recaptured Pools	$ (3,498)	$ (3,857)	$ (13,915)	$ (5,421)
Servicer advance investments | Servicer Advances
Schedule of Equity Method Investments [Line Items]
Unpaid Principal Balance	15,654,419		15,654,419		$ 17,033,753
Excess MSRs
Schedule of Equity Method Investments [Line Items]
Unpaid Principal Balance	44,294,807		$ 44,294,807
Weighted Average Life (Years)			6 years 6 months
Amortized Cost Basis	189,814		$ 189,814
Carrying Value	$ 217,764		$ 217,764		$ 249,366
Excess MSRs | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	32500.00%		32500.00%
Excess MSRs | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	100.00%		100.00%
Excess MSRs | Weighted Average
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	56400.00%		56400.00%
Excess MSRs | Former Manager-managed funds | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Former Manager-managed funds | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	50.00%		50.00%
Excess MSRs | Mr. Cooper | Minimum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	0.00%		0.00%
Excess MSRs | Mr. Cooper | Maximum
Schedule of Equity Method Investments [Line Items]
Interest in Excess MSR	35.00%		35.00%