BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Deferred Rent Receivable and Charges (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Deferred rent receivable	$ 52,619	$ 64,010
Deferred leasing costs, gross	52,414	76,063
Deferred leasing costs, accumulated amortization	23,807	25,914
Deferred offering costs	3,401	2,060
Other deferred costs	$ 121	$ 135