ACQUISITIONS AND DISPOSITIONS - Carrying Value of Assets and Liabilities at Time of Sale (Details) - Disposal Group, Disposed of by Sale, Not Discontinued Operations - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investments in real estate, net	$ 631,740	$ 54,374	$ 4,694
Deferred rent receivable and charges, net	34,071	0	0
Other intangible assets, net	11,283	528	0
Other assets	38	0	0
Total assets	677,132	54,902	4,694
Debt, net	115,037	0	0
Other liabilities	14,029	0	0
Intangible liabilities, net	1,800	0	0
Total liabilities	130,866	$ 0	$ 0
Premium on assumed mortgage	665
Debt assumed by buyers	$ 50,260