DEBT OBLIGATIONS - Schedule of Debt Obligations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Outstanding Face Amount	$ 21,460,632,000
Carrying Value	$ 21,356,679,000	$ 29,237,694,000	$ 25,191,875,000
Weighted Average Funding Cost	5.10%
Weighted Average Life (Years)	1 year 2 months 12 days
Outstanding Face	$ 631,214,506,000
Amortized Cost Basis	25,561,811,000
Carrying Value	27,612,511,000
MSR purchase price holdback	87,700,000	30,931,000
Secured Financing Agreements
Debt Instrument [Line Items]
Outstanding Face Amount	11,260,242,000
Carrying Value	$ 11,257,736,000	20,592,884,000
Weighted Average Funding Cost	5.00%
Weighted Average Life (Years)	4 months 24 days
MSR purchase price holdback	$ 80,500,000
Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	10,200,390,000
Carrying Value	$ 10,098,943,000	8,644,810,000
Weighted Average Funding Cost	5.20%
Weighted Average Life (Years)	2 years 2 months 12 days
Warehouse Credit Facilities-Residential Mortgage Loans | Warehouse Credit Facilities
Debt Instrument [Line Items]
Outstanding Face Amount	$ 2,603,833,000
Carrying Value	$ 2,601,327,000	10,138,297,000
Weighted Average Funding Cost	5.90%
Weighted Average Life (Years)	9 months 18 days
Repurchase agreements	$ 278,600,000
Interest rate, stated percentage	5.10%
Warehouse Credit Facilities-Residential Mortgage Loans | Warehouse Credit Facilities | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	21 years 3 months 18 days
Outstanding Face	$ 3,187,716,000
Amortized Cost Basis	3,114,791,000
Carrying Value	3,020,575,000
Warehouse Credit Facility- Mortgage Loans Receivable | Warehouse Credit Facilities
Debt Instrument [Line Items]
Outstanding Face Amount	1,220,662,000
Carrying Value	$ 1,220,662,000	1,252,660,000
Weighted Average Funding Cost	6.90%
Weighted Average Life (Years)	7 months 6 days
Warehouse Credit Facility- Mortgage Loans Receivable | Warehouse Credit Facilities | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	9 months 18 days
Outstanding Face	$ 1,451,279,000
Amortized Cost Basis	1,451,279,000
Carrying Value	1,451,279,000
Agency RMBS | Secured Financing Agreements
Debt Instrument [Line Items]
Outstanding Face Amount	6,821,788,000
Carrying Value	$ 6,821,788,000	8,386,538,000
Weighted Average Funding Cost	4.10%
Weighted Average Life (Years)	1 month 6 days
Agency RMBS | Secured Financing Agreements | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	8 years 6 months
Outstanding Face	$ 7,213,920,000
Amortized Cost Basis	7,082,133,000
Carrying Value	7,123,127,000
Non-Agency RMBS | Secured Financing Agreements
Debt Instrument [Line Items]
Outstanding Face Amount	609,282,000
Carrying Value	$ 609,282,000	656,874,000
Weighted Average Funding Cost	6.50%
Weighted Average Life (Years)	1 year 1 month 6 days
Non-Agency RMBS | Secured Financing Agreements | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	7 years 1 month 6 days
Outstanding Face	$ 14,824,678,000
Amortized Cost Basis	946,631,000
Carrying Value	946,197,000
SFR properties
Debt Instrument [Line Items]
Carrying Value	822,372,000	357,922,000	5,586,000
SFR properties | Secured Financing Agreements
Debt Instrument [Line Items]
Outstanding Face Amount	4,677,000
Carrying Value	$ 4,677,000	158,515,000
Weighted Average Funding Cost	7.10%
Weighted Average Life (Years)	2 years
SFR properties | Secured Financing Agreements | Collateral
Debt Instrument [Line Items]
Amortized Cost Basis	$ 7,765,000
Carrying Value	7,765,000
SFR properties | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	863,029,000
Carrying Value	$ 817,695,000	199,407,000
Weighted Average Funding Cost	3.60%
Weighted Average Life (Years)	3 years 9 months 18 days
SFR properties | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Amortized Cost Basis	$ 963,547,000
Carrying Value	963,547,000
Excess MSRs
Debt Instrument [Line Items]
Carrying Value	227,596,000	237,835,000	275,088,000
Excess MSRs | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	227,596,000
Carrying Value	$ 227,596,000	237,835,000
Weighted Average Funding Cost	3.70%
Weighted Average Life (Years)	2 years 7 months 6 days
Excess MSRs | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	6 years 1 month 6 days
Outstanding Face	$ 67,454,370,000
Amortized Cost Basis	260,828,000
Carrying Value	317,146,000
MSRs | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	4,800,001,000
Carrying Value	$ 4,791,543,000	4,234,771,000
Weighted Average Funding Cost	6.10%
Weighted Average Life (Years)	2 years 4 months 24 days
MSRs | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	6 years 10 months 24 days
Outstanding Face	$ 532,218,484,000
Amortized Cost Basis	6,811,636,000
Carrying Value	8,833,825,000
Servicer Advance Investments | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	319,276,000
Carrying Value	$ 318,445,000	355,722,000
Weighted Average Funding Cost	6.50%
Weighted Average Life (Years)	1 year 2 months 12 days
Servicer Advance Investments | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	8 years 4 months 24 days
Outstanding Face	$ 341,628,000
Amortized Cost Basis	392,749,000
Carrying Value	$ 398,820,000
Servicer Advances | LIBOR | Secured Notes And Bonds Payable | Minimum
Debt Instrument [Line Items]
Variable interest rate spread	1.20%
Servicer Advances | LIBOR | Secured Notes And Bonds Payable | Maximum
Debt Instrument [Line Items]
Variable interest rate spread	3.30%
Servicer Advances | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	$ 2,364,757,000
Carrying Value	$ 2,361,259,000	2,355,969,000
Weighted Average Funding Cost	4.10%
Weighted Average Life (Years)	1 year 1 month 6 days
Face amount of fixed rate debt	$ 1,200,000,000
Servicer Advances | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	8 months 12 days
Outstanding Face	$ 2,847,234,000
Amortized Cost Basis	2,825,485,000
Carrying Value	2,825,485,000
Residential Mortgage Loans | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	770,897,000
Carrying Value	$ 769,988,000	802,526,000
Weighted Average Funding Cost	5.40%
Weighted Average Life (Years)	1 year 10 months 24 days
Residential Mortgage Loans | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	28 years 6 months
Outstanding Face	$ 775,314,000
Amortized Cost Basis	791,534,000
Carrying Value	791,534,000
Consumer Loans
Debt Instrument [Line Items]
Carrying Value	299,498,000	458,580,000	628,759,000
Consumer Loans | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	330,772,000
Carrying Value	$ 299,498,000	458,580,000
Weighted Average Funding Cost	2.10%
Weighted Average Life (Years)	3 years 3 months 18 days
Consumer Loans | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	3 years 6 months
Outstanding Face	$ 330,397,000
Amortized Cost Basis	343,947,000
Carrying Value	363,725,000
Mortgage Loans Receivable
Debt Instrument [Line Items]
Carrying Value	1,733,581,000	1,252,660,000	$ 0
Mortgage Loans Receivable | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	524,062,000
Carrying Value	$ 512,919,000	$ 0
Weighted Average Funding Cost	5.40%
Weighted Average Life (Years)	3 years 9 months 18 days
Mortgage Loans Receivable | Secured Notes And Bonds Payable | Collateral
Debt Instrument [Line Items]
Weighted Average Life (Years)	7 months 6 days
Outstanding Face	$ 569,486,000
Amortized Cost Basis	569,486,000
Carrying Value	569,486,000
3.7% Secured Corporate Note | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	$ 227,600,000
3.7% Secured Corporate Note | Secured Notes And Bonds Payable | LIBOR
Debt Instrument [Line Items]
Variable interest rate spread	3.70%
2.5% - 3.3% Agency MSR Secured Note And Bond Payable | LIBOR | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	$ 3,000,000,000
2.5% - 3.3% Agency MSR Secured Note And Bond Payable | LIBOR | Secured Notes And Bonds Payable | Minimum
Debt Instrument [Line Items]
Variable interest rate spread	2.50%
2.5% - 3.3% Agency MSR Secured Note And Bond Payable | LIBOR | Secured Notes And Bonds Payable | Maximum
Debt Instrument [Line Items]
Variable interest rate spread	3.30%
3.0% To 5.4% Public Notes | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	$ 1,800,000,000
3.0% To 5.4% Public Notes | Secured Notes And Bonds Payable | Minimum
Debt Instrument [Line Items]
Variable interest rate spread	3.00%
3.0% To 5.4% Public Notes | Secured Notes And Bonds Payable | Maximum
Debt Instrument [Line Items]
Variable interest rate spread	5.40%
3.7% Asset-Backed Notes | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	$ 20,900,000
3.7% Asset-Backed Notes | Secured Notes And Bonds Payable | Maximum
Debt Instrument [Line Items]
Weighted Average Funding Cost	3.70%
Revolving Warehouse Facility Backed Securitization | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Outstanding Face Amount	$ 750,000,000
Revolving Warehouse Facility Backed Securitization | Secured Notes And Bonds Payable | LIBOR
Debt Instrument [Line Items]
Variable interest rate spread	1.10%
Consumer Loan, UPB Class A | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Interest rate, stated percentage	2.00%
Unpaid Principal Balance	$ 277,700,000
Consumer Loan, UPB Class B | Secured Notes And Bonds Payable
Debt Instrument [Line Items]
Interest rate, stated percentage	2.70%
Unpaid Principal Balance	$ 53,000,000