FAIR VALUE MEASUREMENT - Schedule of Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets:
Purchase options related to real estate loans	$ 8,920	$ 6,120
Derivative asset	0	3,461
Liabilities:
Derivative Liablities	16,177	5,042
Recurring basis
Assets:
Purchase options related to real estate loans	8,920	6,120
Recurring basis | Interest rate swaps
Assets:
Derivative asset		3,461
Liabilities:
Derivative Liablities	16,177	5,042
Recurring basis | Level 1
Assets:
Purchase options related to real estate loans	0	0
Recurring basis | Level 1 | Interest rate swaps
Assets:
Derivative asset		0
Liabilities:
Derivative Liablities	0	0
Recurring basis | Level 2
Assets:
Purchase options related to real estate loans	0	0
Recurring basis | Level 2 | Interest rate swaps
Assets:
Derivative asset		3,461
Liabilities:
Derivative Liablities	16,177	5,042
Recurring basis | Level 3
Assets:
Purchase options related to real estate loans	8,920	6,120
Recurring basis | Level 3 | Interest rate swaps
Assets:
Derivative asset		0
Liabilities:
Derivative Liablities	$ 0	$ 0