FAIR VALUE MEASUREMENT - Schedule of Inputs Used in Valuing Assets and Liabilities At Fair Value (Details) - Fair Value, Measurements, Nonrecurring - Total $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 572,505
Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.072
Weighted Average Life (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, term	3 years 7 months 6 days
Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.036
Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.027
Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.336
Performing Loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 191,580
Non-Performing Loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 380,925
Minimum | Performing Loans | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.045
Minimum | Performing Loans | Weighted Average Life (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, term	3 years
Minimum | Performing Loans | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.051
Minimum | Performing Loans | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.008
Minimum | Performing Loans | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.287
Minimum | Non-Performing Loans | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.075
Minimum | Non-Performing Loans | Weighted Average Life (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, term	3 years
Minimum | Non-Performing Loans | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.020
Minimum | Non-Performing Loans | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.029
Minimum | Non-Performing Loans | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.300
Maximum | Performing Loans | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.095
Maximum | Performing Loans | Weighted Average Life (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, term	9 years 1 month 6 days
Maximum | Performing Loans | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.070
Maximum | Performing Loans | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.122
Maximum | Performing Loans | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	1.000
Maximum | Non-Performing Loans | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.075
Maximum | Non-Performing Loans | Weighted Average Life (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, term	3 years
Maximum | Non-Performing Loans | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.020
Maximum | Non-Performing Loans | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.029
Maximum | Non-Performing Loans | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.300
Weighted Average | Performing Loans | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.066
Weighted Average | Performing Loans | Weighted Average Life (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, term	4 years 10 months 24 days
Weighted Average | Performing Loans | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.068
Weighted Average | Performing Loans | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.025
Weighted Average | Performing Loans | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.407
Weighted Average | Non-Performing Loans | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.075
Weighted Average | Non-Performing Loans | Weighted Average Life (Years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, term	3 years
Weighted Average | Non-Performing Loans | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.020
Weighted Average | Non-Performing Loans | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.029
Weighted Average | Non-Performing Loans | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing receivable, measurement input	0.300