EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Numerator for basic and diluted earnings per share:
Income from continuing operations	$ 133,473	$ 152,272	$ 213,533	$ 308,184
Discontinued operations	0	(23)	(10)	(76)
Gain on real estate dispositions	35,827	719	35,875	44,008
Net income	169,300	152,968	249,398	352,116	$ 1,361,112
Net income attributable to noncontrolling interests	2,781	1,137	4,176	2,158
Net income attributable to common stockholders	$ 166,519	$ 151,831	$ 245,222	$ 349,958
Denominator:
Denominator for basic earnings per share—weighted average shares (in shares)	356,228	355,024	356,175	354,719
Effect of dilutive securities:
Stock options (in shares)	115	596	120	501
Restricted stock awards (in shares)	236	225	211	193
OP Unitholder Interests (in shares)	2,421	2,466	2,425	2,506
Denominator for diluted earnings per share—adjusted weighted average shares (in shares)	359,000	358,311	358,931	357,919
Basic earnings per share:
Income from continuing operations (in usd per share)	$ 0.37	$ 0.43	$ 0.60	$ 0.87
Net income attributable to common stockholders (in usd per share)	0.47	0.43	0.69	0.99
Diluted earnings per share:
Income from continuing operations (in usd per share)	0.37	0.42	0.59	0.86
Net income attributable to common stockholders (in usd per share)	$ 0.46	$ 0.42	$ 0.68	$ 0.98