TENANT ORIGINATION AND ABSORPTION COSTS, ABOVE-MARKET LEASE ASSETS AND BELOW-MARKET LEASE LIABILITIES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Tenant Origination and Absorption Costs, Above-Market Lease Assets and Below-Market Lease Liabilities [Abstract]
Tenant Origination and Absorption Costs, Cost	$ 86,392		$ 86,392		$ 95,808
Tenant Origination and Absorption Costs, Accumulated Amortization	(53,697)		(53,697)		(56,886)
Tenant Origination and Absorption Costs, Net Amount	32,695		32,695		38,922
Tenant Origination and Absorption Costs, Amortization expense	(2,518)	$ (7,209)	(5,293)	$ (14,419)
Above-Market Lease Assets, Cost	1,146		1,146		2,661
Above-Market Lease Assets, Accumulated Amortization	(645)		(645)		(2,095)
Above-Market Lease Assets, Net Amount	501		501		566
Above-Market Lease Assets, Amortization expense	(28)	(347)	(65)	(724)
Below-Market Lease Liabilities, Cost	(24,822)		(24,822)		(25,630)
Below-Market Lease Liabilities, Accumulated Amortization	16,475		16,475		15,781
Below-Market Lease Liabilities, Net Amount	(8,347)		(8,347)		$ (9,849)
Below-Market Lease Liabilities, Amortization expense	$ 742	$ 1,499	$ 1,502	$ 2,824