REAL ESTATE - Operating Leases, Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Operating Leased Assets [Line Items]
Deferred rent recognized			$ 4,041,000	$ 4,245,000
Deferred rent receivables	$ 84,000,000.0		84,000,000.0		$ 80,000,000.0
Incentive to lessee	20,600,000		20,600,000		21,000,000.0
Lease Revenue
Operating Leased Assets [Line Items]
Bad debt expense (recovery)	2,800,000	$ 400,000	7,200,000	1,800,000
Operating, Maintenance and Management Expense
Operating Leased Assets [Line Items]
Bad debt expense (recovery)	0	$ (100,000)	0	$ (400,000)
Other liabilities, at fair value
Operating Leased Assets [Line Items]
Security deposit liability	$ 8,400,000		$ 8,400,000		$ 8,800,000
Maximum
Operating Leased Assets [Line Items]
Operating leases, term of contract	16 years 9 months 18 days		16 years 9 months 18 days
Weighted Average
Operating Leased Assets [Line Items]
Operating leases, term of contract	4 years 9 months 18 days		4 years 9 months 18 days