FAIR VALUE MEASUREMENTS - Schedule of Inputs Used In Valuing Residential Mortgage Loans, Consumer Loans, Mortgage Loans Receivable, Derivatives, and Mortgage Backed Securities (Details) $ in Thousands	Mar. 31, 2022 USD ($) security	Dec. 31, 2021 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage loans receivable, at fair value	$ 1,670,415	$ 1,515,762
Residential Mortgage Loans Held-for-Sale, At Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, fair value	1,387,969
Residential Mortgage Loans, Held-for-Investment, at Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans, held-for-investment, fair value	$ 547,404
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Minimum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.033
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Minimum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.021
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Minimum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.003
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Minimum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.200
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Maximum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.075
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Maximum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.200
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Maximum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.182
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Maximum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.950
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Weighted Average | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.072
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Weighted Average | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.083
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Weighted Average | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.051
Residential Mortgage Loans, Held-for-Investment, at Fair Value | Weighted Average | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for investment, measurement input	0.719
Consumer Loans Held-for-Investment, At Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans	$ 462,055
Consumer Loans Held-for-Investment, At Fair Value | Minimum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.000
Consumer Loans Held-for-Investment, At Fair Value | Minimum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.000
Consumer Loans Held-for-Investment, At Fair Value | Minimum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.000
Consumer Loans Held-for-Investment, At Fair Value | Minimum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.000
Consumer Loans Held-for-Investment, At Fair Value | Maximum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.075
Consumer Loans Held-for-Investment, At Fair Value | Maximum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.233
Consumer Loans Held-for-Investment, At Fair Value | Maximum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.043
Consumer Loans Held-for-Investment, At Fair Value | Maximum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.645
Consumer Loans Held-for-Investment, At Fair Value | Weighted Average | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.075
Consumer Loans Held-for-Investment, At Fair Value | Weighted Average | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.233
Consumer Loans Held-for-Investment, At Fair Value | Weighted Average | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.043
Consumer Loans Held-for-Investment, At Fair Value | Weighted Average | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Consumer loans, held-for-investment, measurement input	0.645
Mortgage Loans Receivable
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage loans receivable, at fair value	$ 1,375,273
Mortgage Loans Receivable | Minimum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage loans receivable, at fair value, measurement input | security	0.055
Mortgage Loans Receivable | Maximum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage loans receivable, at fair value, measurement input | security	0.075
Mortgage Loans Receivable | Weighted Average | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage loans receivable, at fair value, measurement input | security	0.065
IRLCs
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, fair value	$ (15,908)
IRLCs | Minimum | Loan Funding Probability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, measurement input	0.000
IRLCs | Minimum | Fair Value of Initial Servicing Rights (Bps)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, measurement input	0.00000
IRLCs | Maximum | Loan Funding Probability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, measurement input	1.000
IRLCs | Maximum | Fair Value of Initial Servicing Rights (Bps)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, measurement input	0.07353
IRLCs | Weighted Average | Loan Funding Probability
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, measurement input	0.855
IRLCs | Weighted Average | Fair Value of Initial Servicing Rights (Bps)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Derivative, measurement input	0.01687
Mortgage-Backed Securities Issued
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, fair value	$ 762,421
Mortgage-Backed Securities Issued | Minimum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.027
Mortgage-Backed Securities Issued | Minimum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0
Mortgage-Backed Securities Issued | Minimum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0
Mortgage-Backed Securities Issued | Minimum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0
Mortgage-Backed Securities Issued | Maximum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.065
Mortgage-Backed Securities Issued | Maximum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.400
Mortgage-Backed Securities Issued | Maximum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.043
Mortgage-Backed Securities Issued | Maximum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.937
Mortgage-Backed Securities Issued | Weighted Average | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.043
Mortgage-Backed Securities Issued | Weighted Average | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.242
Mortgage-Backed Securities Issued | Weighted Average | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.041
Mortgage-Backed Securities Issued | Weighted Average | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.896
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, fair value	$ 1,333,811
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Minimum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.037
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Minimum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.021
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Minimum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.001
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Minimum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.031
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Maximum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.074
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Maximum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.143
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Maximum | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.182
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Maximum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.680
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Weighted Average | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.045
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Weighted Average | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.093
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Weighted Average | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.014
Non-Purchased Credit Deteriorated | Residential Mortgage Loans Held-for-Sale, At Fair Value | Weighted Average | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held for sale, measurement input	0.344
Originated | Residential Mortgage Loans Held-for-Sale, At Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, fair value	$ 54,158