REAL ESTATE HELD FOR INVESTMENT - Operating Leases, Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) tenant	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) tenant	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Operating Leased Assets [Line Items]
Recognition of deferred revenue, net of discontinued operations			$ 1,700	$ 2,200
Deferred rent receivables	$ 15,500		15,500		$ 13,600
Incentive to lessee	$ 3,200		$ 3,200		3,100
Number of tenants | tenant	239		239
Adjustments to rental income	$ 600	$ 100	$ 800	$ 200
Prepaid expenses and other assets (Other liabilities)
Operating Leased Assets [Line Items]
Security deposit liability	$ 4,300		$ 4,300		$ 4,300
Maximum
Operating Leased Assets [Line Items]
Operating lease, term	11 years 8 months 12 days		11 years 8 months 12 days
Weighted Average
Operating Leased Assets [Line Items]
Operating lease, term	4 years 6 months		4 years 6 months
Apartment Building
Operating Leased Assets [Line Items]
Operating lease, term	1 year		1 year