LOANS RECEIVABLE AND OTHER INVESTMENTS - Composition of Loans Receivable and Other Investments (Details) $ in Thousands	Sep. 30, 2020 USD ($) investment preferredEquityInvestment loan	Dec. 31, 2019 USD ($)
Loans Receivable:
Quantity | loan	19
Principal balance	$ 66,316	$ 67,527
Book Value	62,363	63,634
Allowance for loan losses	(1,287)	(564)
Book Value	$ 61,076	63,070
Weighted Average Contractual Interest Rate / Rate of Return	7.80%
Weighted Average Annualized Effective Interest Rate / Rate of Return	7.90%
Other Investments:
Quantity | preferredEquityInvestment	6
Principal Balance	$ 42,533	43,893
Book Value	$ 42,744	44,304
Weighted Average Contractual Interest Rate / Rate of Return	11.30%
Weighted Average Annualized Effective Interest Rate / Rate of Return	11.30%
Total Quantity | investment	25
Total Principal Balance	$ 108,849
Total Book Value	$ 103,820	107,374
Total Weighted Average Contractual Interest Rate / Rate of Return	9.20%
Total Weighted Average Annualized Effective Interest Rate / Rate of Return	9.30%
Mortgage
Loans Receivable:
Quantity | loan	1
Principal balance	$ 19,000
Book Value	$ 19,000	19,000
Weighted Average Contractual Interest Rate / Rate of Return	10.00%
Weighted Average Annualized Effective Interest Rate / Rate of Return	10.00%
Construction
Loans Receivable:
Quantity | loan	1
Principal balance	$ 3,343
Book Value	$ 3,353	2,487
Weighted Average Contractual Interest Rate / Rate of Return	8.00%
Weighted Average Annualized Effective Interest Rate / Rate of Return	7.80%
Other
Loans Receivable:
Quantity | loan	17
Principal balance	$ 43,973
Book Value	$ 40,010	$ 42,147
Weighted Average Contractual Interest Rate / Rate of Return	6.80%
Weighted Average Annualized Effective Interest Rate / Rate of Return	6.90%