BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Deferred Rent Receivable and Charges (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deferred Rent Receivable and Charges
Deferred rent receivable	$ 53,597	$ 52,619
Deferred leasing costs	49,253	52,414
Deferred leasing costs, accumulated amortization	21,163	23,807
Deferred offering costs	3,826	3,401
Other deferred costs	$ 488	$ 121