FAIR VALUE MEASUREMENTS - Information Regarding Inputs used in Valuing Excess MSRs Owned Directly and through Equity Method Investees (Details)	12 Months Ended
	Dec. 31, 2023 $ / Loan	Dec. 31, 2022 $ / Loan
Prepayment Rate | MSRs And MSR Financing Receivables | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.003	0.013
Prepayment Rate | MSRs And MSR Financing Receivables | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.837	0.978
Prepayment Rate | MSRs And MSR Financing Receivables | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.086	0.092
Prepayment Rate | MSRs And MSR Financing Receivables | Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.006	0.026
Prepayment Rate | MSRs And MSR Financing Receivables | Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.837	0.978
Prepayment Rate | MSRs And MSR Financing Receivables | Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.073	0.080
Prepayment Rate | MSRs And MSR Financing Receivables | Non-Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.003	0.013
Prepayment Rate | MSRs And MSR Financing Receivables | Non-Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.834	0.932
Prepayment Rate | MSRs And MSR Financing Receivables | Non-Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.122	0.150
Prepayment Rate | MSRs And MSR Financing Receivables | Ginnie Mae | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.050	0.028
Prepayment Rate | MSRs And MSR Financing Receivables | Ginnie Mae | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.819	0.812
Prepayment Rate | MSRs And MSR Financing Receivables | Ginnie Mae | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.105	0.103
Prepayment Rate | Directly Held | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.024	0.028
Prepayment Rate | Directly Held | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.122	0.135
Prepayment Rate | Directly Held | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.065	0.073
Prepayment Rate | Held through Equity Method Investees | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.063	0.084
Prepayment Rate | Held through Equity Method Investees | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.090	0.11
Prepayment Rate | Held through Equity Method Investees | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.078	0.094
Delinquency | MSRs And MSR Financing Receivables | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.000	0.001
Delinquency | MSRs And MSR Financing Receivables | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	1.000	0.800
Delinquency | MSRs And MSR Financing Receivables | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.061	0.053
Delinquency | MSRs And MSR Financing Receivables | Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.000	0.001
Delinquency | MSRs And MSR Financing Receivables | Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	1.000	0.667
Delinquency | MSRs And MSR Financing Receivables | Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.023	0.020
Delinquency | MSRs And MSR Financing Receivables | Non-Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.009	0.010
Delinquency | MSRs And MSR Financing Receivables | Non-Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.833	0.750
Delinquency | MSRs And MSR Financing Receivables | Non-Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.232	0.211
Delinquency | MSRs And MSR Financing Receivables | Ginnie Mae | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.003	0.002
Delinquency | MSRs And MSR Financing Receivables | Ginnie Mae | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.800	0.800
Delinquency | MSRs And MSR Financing Receivables | Ginnie Mae | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.097	0.089
Delinquency | Directly Held | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.002	0.002
Delinquency | Directly Held | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.088	0.101
Delinquency | Directly Held | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.043	0.036
Delinquency | Held through Equity Method Investees | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.022	0.029
Delinquency | Held through Equity Method Investees | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.056	0.054
Delinquency | Held through Equity Method Investees | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.035	0.039
Recapture Rate | Directly Held | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0	0
Recapture Rate | Directly Held | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.911	0.914
Recapture Rate | Directly Held | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.552	0.554
Recapture Rate | Held through Equity Method Investees | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.451	0.454
Recapture Rate | Held through Equity Method Investees | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.643	0.64
Recapture Rate | Held through Equity Method Investees | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.590	0.587
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0003	0.0002
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0242	0.0216
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0033	0.0034
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0006	0.0007
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0104	0.0104
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0027	0.0030
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Non-Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0003	0.0002
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Non-Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0242	0.0216
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Non-Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0046	0.0046
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Ginnie Mae | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0019	0.0011
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Ginnie Mae | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0082	0.0086
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | MSRs And MSR Financing Receivables | Ginnie Mae | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0043	0.0041
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | Directly Held | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0001	0.0006
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | Directly Held | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0055	0.0031
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | Directly Held | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0020	0.0019
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | Held through Equity Method Investees | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0016	0.0015
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | Held through Equity Method Investees | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0025	0.0026
Mortgage Servicing Amount or Excess Mortgage Servicing Amount (bps) | Held through Equity Method Investees | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	0.0021	0.0021
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	0 years	0 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	40 years	39 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	24 years	24 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	0 years	0 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	40 years	39 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	23 years	23 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Non-Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	0 years	0 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Non-Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	40 years	36 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Non-Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	21 years	24 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Ginnie Mae | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	1 year	0 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Ginnie Mae | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	39 years	39 years
Collateral Weighted Average Maturity (Years) | MSRs And MSR Financing Receivables | Ginnie Mae | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	27 years	27 years
Collateral Weighted Average Maturity (Years) | Directly Held | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	11 years	11 years
Collateral Weighted Average Maturity (Years) | Directly Held | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	27 years	29 years
Collateral Weighted Average Maturity (Years) | Directly Held | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	20 years	21 years
Collateral Weighted Average Maturity (Years) | Held through Equity Method Investees | Excess MSRs | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	14 years	15 years
Collateral Weighted Average Maturity (Years) | Held through Equity Method Investees | Excess MSRs | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	21 years	22 years
Collateral Weighted Average Maturity (Years) | Held through Equity Method Investees | Excess MSRs | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Collateral Weighted Average Maturity (Years)	18 years	19 years
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	6.38	6.80
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	7.08	7.00
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	6.99	6.90
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Non-Agency | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	7.50	7.30
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Non-Agency | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	9.57	17.20
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Non-Agency | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	9.16	8.70
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Ginnie Mae | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input	8.37	8.30
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Ginnie Mae | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input		8.40
Measurement Input, Servicing Cost | MSRs And MSR Financing Receivables | Ginnie Mae | Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Servicing asset, measurement input		8.30