EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator for basic and diluted earnings per share:
Income from continuing operations attributable to common stockholders, including real estate dispositions	$ 149,754	$ 138,653	$ 270,619	$ 256,669
Discontinued operations	67	(255)	(356)	2,776
Net income attributable to common stockholders	$ 149,821	$ 138,398	$ 270,263	$ 259,445
Denominator:
Denominator for basic earnings per share—weighted average shares	330,715	293,988	327,890	293,932
Effect of dilutive securities:
Stock options (in shares)	341	530	436	456
Restricted stock awards (in shares)	41	59	60	53
OP units (in shares)	2,929	1,927	3,038	1,928
Denominator for diluted earnings per share—adjusted weighted average shares	334,026	296,504	331,424	296,369
Basic earnings per share:
Income from continuing operations attributable to common stockholders, including real estate dispositions (in usd per share)	$ 0.45	$ 0.47	$ 0.82	$ 0.87
Discontinued operations (in usd per share)	0.00	0.00	0.00	0.01
Net income attributable to common stockholders (in usd per share)	0.45	0.47	0.82	0.88
Diluted earnings per share:
Income from continuing operations attributable to common stockholders, including real estate dispositions (in usd per share)	0.45	0.47	0.82	0.87
Discontinued operations (in usd per share)	0.00	0.00	0.00	0.01
Net income attributable to common stockholders (in usd per share)	$ 0.45	$ 0.47	$ 0.82	$ 0.88