REAL ESTATE AND RELATED LEASE INTANGIBLES, NET - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Business Acquisition [Line Items]
Gross intangible assets	$ 179,400		$ 189,500
Accumulated amortization	61,100		60,900
Net intangible assets	118,300		128,600
Unamortized favorable/unfavorable lease intangibles	6,100		8,900
Net increase in operating lease income, amortization of below market lease intangibles	600	$ 300
Unbilled rent receivables	700		900
Unencumbered real estates	96,500		$ 128,700
Weighted average amortization period for intangible assets acquired		34 years 2 months 12 days
Revenue recorded from acquisitions		$ 36
Earnings (losses) recorded from acquisitions		36
Net loss	(300)
Above Market Leases
Business Acquisition [Line Items]
Net reduction in operating lease income, amortization of above market leases	$ (200)	$ (300)