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		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to common shareholders	$ (28,482)	$ (29,042)	$ (64,872)	$ 18,527
Net income (loss) attributable to common unitholders	(28,948)	(29,748)	(66,149)	19,026
Less: Dividends on Participating Securities	(856)	(806)	(1,708)	(1,605)
Basic Net Income (Loss) Attributable To Common Stockholders	(29,338)	(29,848)	(66,580)	16,922
Noncontrolling Interests In Earnings Of Common Unitholders	0	0	0	499
Diluted Net Income (Loss) Attributable to Common Stockholders	(29,338)	(29,848)	(66,580)	17,421
Weighted average number of common shares outstanding	266,748	252,640	262,556	252,524
Weighted Average Limited Partnership Units Outstanding	0	0	0	6,798
Other potential dilutive shares	0	0	0	68
Weighted average number of common shares and potential dilutive securities	266,748	252,640	262,556	259,390
Subsidiary of Common Parent [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to common unitholders	(28,948)	(29,748)	(66,149)	19,026
Less: Dividends on Participating Securities	(856)	(806)	(1,708)	(1,605)
Basic and diluted net income (loss) attributable to common unitholders	$ (29,804)	$ (30,554)	$ (67,857)	$ 17,421
Weighted average number of Common Units outstanding	271,317	259,849	267,716	259,322
Other potential dilutive units	0	0	0	68
Weighted average number of Common Units and potential dilutive securities	271,317	259,849	267,716	259,390