MORTGAGE SERVICING RIGHTS AND MSR FINANCING RECEIVABLES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021		Mar. 31, 2020	Dec. 31, 2020		Jan. 31, 2018	Jul. 31, 2017
Schedule of MSRs [Line Items]
Residential mortgage loans subject to repurchase	$ 1,493,449	[1]	$ 1,452,005	$ 1,452,005	[1]
Residential mortgage loans, held-for-sale	5,923,555			5,215,703
Reserve for non-recovery advances	27,500			$ 22,900
Ginnie Mae Loans
Schedule of MSRs [Line Items]
Residential mortgage loans subject to repurchase	1,500,000
Residential mortgage loans, held-for-sale	843,800
Ocwen
Schedule of MSRs [Line Items]
UPB of Underlying Mortgages						$ 86,800,000	$ 110,000,000
Mortgage Loans Subserviced
Schedule of MSRs [Line Items]
UPB of Underlying Mortgages	74,600,000		74,000,000
Subservicing revenue	$ 43,500		$ 41,200
LoanCare
Schedule of MSRs [Line Items]
Subservicer percent of UPB	15.70%
PHH Mortgage Corporation
Schedule of MSRs [Line Items]
Subservicer percent of UPB	15.40%
Mr. Cooper
Schedule of MSRs [Line Items]
Subservicer percent of UPB	15.30%
Flagstar Bank
Schedule of MSRs [Line Items]
Subservicer percent of UPB	0.60%
NewRez
Schedule of MSRs [Line Items]
Subservicer percent of UPB	53.00%
Ocwen | New Residential Mortgage LLC
Schedule of MSRs [Line Items]
Unpaid principal balance of underlying loans, transferred	$ 66,700,000

[1] See Note 5 for details.