SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplement Disclosures Related to Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accounting Policies [Abstract]
Total interest costs incurred	$ 14,277	$ 13,702
Interest capitalized	457	371
Interest expense	13,820	13,331
Cash paid for interest, net of amounts capitalized	14,059	10,708
Cash paid for income taxes	31	46
Accounts payable and accrued liabilities for construction in progress	(706)	577
Accrued leasing commissions	710	193
Reduction to capital for prepaid offering costs	$ 176	$ 0