MORTGAGE LOANS, NET - Loans by Maturity (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Loan	Dec. 31, 2018 USD ($) Loan	Dec. 31, 2017 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Outstanding Balance	$ 12,682	$ 36,297
Less: valuation allowance	(12,682)	(13,063)	$ (12,682)
Net Carrying Amount	$ 0	$ 23,234	$ 19,668
Total Loan Percentage	100.00%	100.00%
Number of Loans | Loan	2	6
Matured
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Outstanding Balance	$ 12,682	$ 20,999
Percentage of Loans	100.00%	57.90%
Number of Loans | Loan	2	3
Q4 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Outstanding Balance		$ 15,298
Percentage of Loans		42.10%
Number of Loans | Loan		3