FAIR VALUE DISCLOSURES - Narrative (Details) - Discount rate	Sep. 30, 2021
Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans receivable, measurement input	0.07
Preferred equity investments, measurement input	0.10
Minimum | Secured Indebtedness
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt, measurement input	0.02
Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans receivable, measurement input	0.11
Preferred equity investments, measurement input	0.15
Maximum | Secured Indebtedness
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt, measurement input	0.03
Weighted Average
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans receivable, measurement input	0.09
Preferred equity investments, measurement input	0.11
Weighted Average | Secured Indebtedness
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt, measurement input	0.03