FAIR VALUE MEASUREMENT - Schedule of Financial Instruments Measured at Fair Value (Details) - Recurring basis - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets:
Purchase Options related to real estate loans	$ 8,138	$ 8,920
Level 1
Assets:
Purchase Options related to real estate loans	0	0
Level 2
Assets:
Purchase Options related to real estate loans	0	0
Level 3
Assets:
Purchase Options related to real estate loans	8,138	8,920
Interest rate swaps
Liabilities:
Derivative liabilities	35,221	16,177
Interest rate swaps | Level 1
Liabilities:
Derivative liabilities	0	0
Interest rate swaps | Level 2
Liabilities:
Derivative liabilities	35,221	16,177
Interest rate swaps | Level 3
Liabilities:
Derivative liabilities	$ 0	$ 0