Net Income (Loss) Per Common Share Reconciling the Components of Basic and Diluted Net Income (Loss) per Common Share (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to common shareholders/unitholders	$ (6,067)	$ (28,230)	$ 83,470	$ (93,102)
Less: Dividends on Participating Securities	(650)	(680)	(2,024)	(2,388)
Basic Net Income (Loss) Attributable To Common Stockholders	(6,717)	(28,910)	81,446	(95,490)
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable	0	0	1,142	0
Diluted Net Income (Loss) Attributable to Common Stockholders	(6,717)	(28,910)	82,588	(95,490)
Weighted average number of common shares/units outstanding	324,895	270,289	320,810	265,153
Weighted Average Limited Partnership Units Outstanding	0	0	4,393	0
Other potential dilutive shares/units	0	0	177	0
Weighted average number of common shares/units and potential dilutive securities	324,895	270,289	325,380	265,153
Subsidiary of Common Parent [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to common shareholders/unitholders	(6,159)	(28,689)	84,612	(94,838)
Less: Dividends on Participating Securities	(650)	(680)	(2,024)	(2,388)
Basic Net Income (Loss) Attributable To Common Stockholders	$ (6,809)	$ (29,369)	$ 82,588	$ (97,226)
Weighted average number of common shares/units outstanding	329,283	274,800	325,203	270,095
Other potential dilutive shares/units	0	0	177	0
Weighted average number of common shares/units and potential dilutive securities	329,283	274,800	325,380	270,095