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, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net income (loss) attributable to common shareholders	$ (29,042)	$ (42,391)	$ 18,527	$ (57,655)
Less: Dividends on participating securities	(806)	(505)	(1,605)	(1,005)
Basic net income (loss) attributable to common shareholders	(29,848)	(42,896)	16,922	(58,660)
Noncontrolling interest in earnings of common unitholders			(499)
Diluted net income (loss) attributable to common shareholders	$ (29,848)	$ (42,896)	$ 17,421	$ (58,660)
Weighted average number of common shares outstanding	252,640	227,082	252,524	225,625
Weighted average partnership Units outstanding			6,798
Other potential dilutive shares			68
Weighted average number of common shares and potential dilutive securities	252,640	227,082	259,390	225,625
3.75% Exchangeable Senior Notes [Member]
Interest rate stated on the debt instrument	3.75%		3.75%

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Interest rate stated in the contractual debt agreement.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Weighted average number of general partnership units outstanding determined by relating the portion of time within a reporting period that general partnership units have been outstanding to the total time in that period.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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