EARNINGS PER COMMON SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Numerator for basic and diluted earnings per share:
Income from continuing operations attributable to common stockholders	$ 132,635	$ 42,731	$ 250,635	$ 90,099
Discontinued operations	(18,055)	31,294	(23,862)	74,552
Net income attributable to common stockholders	$ 114,580	$ 74,025	$ 226,773	$ 164,651
Denominator:
Denominator for basic earnings per share - weighted average shares	292,635	290,170	292,049	289,281
Effect of dilutive securities:
Stock options (in shares)	567	499	627	506
Restricted stock awards (in shares)	148	72	134	68
OP units (in shares)	1,773	1,851	1,774	1,856
Denominator for diluted earnings per share - adjusted weighted average shares	295,123	292,592	294,584	291,711
Basic earnings per share:
Income from continuing operations attributable to common stockholders	$ 0.45	$ 0.15	$ 0.86	$ 0.31
Discontinued operations (in dollars per share)	$ (0.06)	$ 0.11	$ (0.08)	$ 0.26
Net income attributable to common stockholders	$ 0.39	$ 0.26	$ 0.78	$ 0.57
Diluted earnings per share:
Income from continuing operations attributable to common stockholders	$ 0.45	$ 0.14	$ 0.85	$ 0.30
Discontinued operations	$ (0.06)	$ 0.11	$ (0.08)	$ 0.26
Net income attributable to common stockholders	$ 0.39	$ 0.25	$ 0.77	$ 0.56