FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value Measurement Inputs (Details) - Valuation Technique, Discounted Cash Flow	Dec. 31, 2020	Dec. 31, 2019
SBA 7(a) loans receivable, Paycheck Protection Program | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0100
Minimum | SBA 7(a) loans receivable, subject to credit risk | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0650	0.0525
Minimum | SBA 7(a) loans receivable, subject to credit risk | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0400	0.0985
Minimum | SBA 7(a) loans receivable, subject to loan-backed notes | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0550	0.0525
Minimum | SBA 7(a) loans receivable, subject to loan-backed notes | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0488	0.1341
Minimum | SBA 7(a) loans receivable, subject to secured borrowings | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0700	0.0675
Minimum | SBA 7(a) loans receivable, subject to secured borrowings | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0500	0.1177
Maximum | SBA 7(a) loans receivable, subject to credit risk | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0825	0.0775
Maximum | SBA 7(a) loans receivable, subject to credit risk | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.1750	0.1750
Maximum | SBA 7(a) loans receivable, subject to loan-backed notes | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0800	0.0725
Maximum | SBA 7(a) loans receivable, subject to loan-backed notes | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.1750	0.1680
Maximum | SBA 7(a) loans receivable, subject to secured borrowings | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.0775	0.0750
Maximum | SBA 7(a) loans receivable, subject to secured borrowings | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input for loans receivable	0.1750	0.1680