CONSOLIDATED STATEMENT OF EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Total Stockholders' Equity	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Noncontrolling Interests
Balance at Dec. 31, 2012	$ 3,416,251	$ 3,077,529	$ 1,375	$ 3,715,895	$ (639,741)	$ 338,722
Balance (in shares) at Dec. 31, 2012	137,507,010		137,507,010
Increase (Decrease) in Stockholders' Equity
Net income	22,530	18,092			18,092	4,438
Share and unit-based compensation plans	5,137	5,137		5,137
Share and unit-based compensation plans (in shares)			60,020
Distributions paid ($0.58) per share	(79,798)	(79,798)			(79,798)
Distributions to noncontrolling interests	(6,409)					(6,409)
Other	(98)	(98)		(98)
Conversion of noncontrolling interests to common shares		974	1	973		(974)
Conversion of noncontrolling interests to common shares (in shares)			61,373
Redemption of noncontrolling interests	(1,022)	(703)		(703)		(319)
Adjustment of noncontrolling interest in Operating Partnership		(4,113)		(4,113)		4,113
Balance at Mar. 31, 2013	$ 3,356,591	$ 3,017,020	$ 1,376	$ 3,717,091	$ (701,447)	$ 339,571
Balance (in shares) at Mar. 31, 2013	137,628,403		137,628,403