EARNINGS PER COMMON SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator for basic and diluted earnings per share:
Income from continuing operations attributable to common stockholders	$ 127,380	$ 115,606	$ 378,748	$ 206,472
Discontinued operations	(9,084)	(3,724)	(33,679)	70,061
Net income attributable to common stockholders	$ 118,296	$ 111,882	$ 345,069	$ 276,533
Denominator:
Denominator for basic earnings per share - weighted average shares	292,818	294,928	292,308	291,177
Effect of dilutive securities:
Stock options (in shares)	483	522	578	509
Restricted stock awards (in shares)	75	121	114	86
OP units (in shares)	1,814	1,836	1,788	1,850
Denominator for diluted earnings per share - adjusted weighted average shares	295,190	297,407	294,788	293,622
Basic earnings per share:
Income from continuing operations attributable to common stockholders	$ 0.43	$ 0.39	$ 1.30	$ 0.71
Discontinued operations (in dollars per share)	$ (0.03)	$ (0.01)	$ (0.12)	$ 0.24
Net income attributable to common stockholders	$ 0.40	$ 0.38	$ 1.18	$ 0.95
Diluted earnings per share:
Income from continuing operations attributable to common stockholders	$ 0.43	$ 0.39	$ 1.28	$ 0.70
Discontinued operations	$ (0.03)	$ (0.01)	$ (0.11)	$ 0.24
Net income attributable to common stockholders	$ 0.40	$ 0.38	$ 1.17	$ 0.94