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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Tenant Origination and Absorption Costs, Above-Market Lease Assets and Below-Market Lease Liabilities [Abstract]
Tenant Origination and Absorption Costs, Cost	$ 219,080		$ 219,080		$ 230,576
Tenant Origination and Absorption Costs, Accumulated Amortization	(112,581)		(112,581)		(108,078)
Tenant Origination and Absorption Costs, Net Amount	106,499		106,499		122,498
Tenant Origination and Absorption Costs, Amortization expense	(7,856)	$ (11,013)	(15,998)	$ (22,119)
Above-Market Lease Assets, Cost	11,956		11,956		12,301
Above-Market Lease Assets, Accumulated Amortization	(6,963)		(6,963)		(6,440)
Above-Market Lease Assets, Net Amount	4,993		4,993		5,861
Above-Market Lease Assets, Amortization expense	(439)	(544)	(895)	(1,247)
Below-Market Lease Liabilities, Cost	(43,602)		(43,602)		(47,459)
Below-Market Lease Liabilities, Accumulated Amortization	22,469		22,469		22,849
Below-Market Lease Liabilities, Net Amount	(21,133)		(21,133)		$ (24,610)
Below-Market Lease Liabilities, Amortization expense	$ 1,655	$ 2,505	$ 3,482	$ 4,779