PRO FORMA FINANCIAL INFORMATION (UNAUDITED) - Summary of Pro Forma Information (Details) - Recent Real Estate Acquisitions - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition, Pro Forma Information [Abstract]
Revenues	$ 631,041	$ 627,475
Net income attributable to common stockholders	$ 292,551	$ 225,331
Net income attributable to common stockholders, per:
Basic common share (in dollars per share)	$ 1.78	$ 1.41
Diluted common share (in dollars per share)	$ 1.78	$ 1.41
Weighted-average number of common shares outstanding, basic (in shares)	164,361,139	159,319,612
Weighted-average number of common shares outstanding, diluted (in shares)	164,582,331	159,556,033