EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator for basic and diluted earnings per share:
Income from continuing operations attributable to common stockholders, including real estate dispositions	$ 45,235	$ 90,961	$ 279,681	$ 289,551
Discontinued operations	(22,383)	18,171	13,434	79,026
Net income attributable to common stockholders	$ 22,852	$ 109,132	$ 293,115	$ 368,577
Denominator:
Denominator for basic earnings per share—weighted average shares (in shares)	332,491	294,030	329,440	293,965
Effect of dilutive securities:
Stock options (in shares)	307	492	401	468
Restricted stock awards (in shares)	22	47	49	51
OP units (in shares)	3,518	1,926	3,320	1,927
Denominator for diluted earnings per share—adjusted weighted average shares (in shares)	336,338	296,495	333,210	296,411
Basic earnings per share:
Income from continuing operations attributable to common stockholders, including real estate dispositions (in usd per share)	$ 0.14	$ 0.31	$ 0.85	$ 0.98
Discontinued operations (in usd per share)	(0.07)	0.06	0.04	0.27
Net income attributable to common stockholders (in usd per share)	0.07	0.37	0.89	1.25
Diluted earnings per share:
Income from continuing operations attributable to common stockholders, including real estate dispositions (in usd per share)	0.14	0.31	0.84	0.97
Discontinued operations (in usd per share)	(0.07)	0.06	0.04	0.27
Net income attributable to common stockholders (in usd per share)	$ 0.07	$ 0.37	$ 0.88	$ 1.24