TENANT ORIGINATION AND ABSORPTION COSTS, ABOVE-MARKET LEASE ASSETS AND BELOW-MARKET LEASE LIABILITIES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 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	$ 90,017		$ 95,808
Tenant Origination and Absorption Costs, Accumulated Amortization	(54,804)		(56,886)
Tenant Origination and Absorption Costs, Net Amount	35,213		38,922
Tenant Origination and Absorption Costs, Amortization expense	(2,775)	$ (7,210)
Above-Market Lease Assets, Cost	1,168		2,661
Above-Market Lease Assets, Accumulated Amortization	(639)		(2,095)
Above-Market Lease Assets, Net Amount	529		566
Above-Market Lease Assets, Amortization expense	(37)	(377)
Below-Market Lease Liabilities, Cost	(25,402)		(25,630)
Below-Market Lease Liabilities, Accumulated Amortization	16,313		15,781
Below-Market Lease Liabilities, Net Amount	(9,089)		$ (9,849)
Below-Market Lease Liabilities, Amortization expense	$ 760	$ 1,325