Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
BASIC
Income (loss) from continuing operations attributable to common shareholders	$ 163,417	$ (22,448)	$ 162,893	$ (54,911)
Income (loss) from discontinuing operations attributable to common shareholders	5,533	(14,600)	686	(56,314)
Net loss attributable to common shareholders	168,950	(37,048)	163,579	(111,225)
Weighted-average number of common shares outstanding (shares)	154,980,137	157,205,530	154,564,041	151,676,401
Loss from continuing operations (dollars per share)	$ 1.05	$ (0.14)	$ 1.05	$ (0.36)
Income (loss) from discontinued operations (dollars per share)	$ 0.04	$ (0.10)	$ 0.01	$ (0.37)
Net loss attributable to common shareholders (dollars per share)	$ 1.09	$ (0.24)	$ 1.06	$ (0.73)
DILUTED
Income (loss) from continuing operations attributable to common shareholders	163,417	(22,448)	162,893	(54,911)
Impact of assumed conversions:
Share Options	0	0	0	0
Operating Partnership Units	475	0	913	0
6% Convertible Guaranteed Notes	2,327	0	6,980	0
Series C Preferred shares	1,573	0	4,489	0
Income (loss) from continuing operations attributable to common shareholders		(22,448)	175,275	(54,911)
Income (loss) from discontinuing operations attributable to common shareholders	5,533	(14,600)	686	(56,314)
Net income (loss) attributable to common shareholders	173,325	(37,048)	175,961	(111,225)
Weighted-average number of common shares outstanding (shares)	154,980,137	157,205,530	154,564,041	151,676,401
Effect of dilutive securities:
Share Options	344,721	0	279,699	0
Operating Partnership Units	4,400,389	0	4,479,451	0
6% Convertible Guaranteed Notes	16,419,347	0	16,412,836	0
Series C Preferred shares	4,710,570	0	4,713,043	0
Weighted-average common shares outstanding	180,855,164	157,205,530	180,449,070	151,676,401
Income (loss) per common share:
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.93	$ (0.14)	$ 0.97	$ (0.36)
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$ 0.03	$ (0.10)	$ 0.01	$ (0.37)
Net income (loss) attributable to common shareholders	$ 0.96	$ (0.24)	$ 0.98	$ (0.73)
Payments for Repurchase of Preferred Stock and Preference Stock			70,000	1,431
Series B
Income (loss) per common share:
Payments for Repurchase of Preferred Stock and Preference Stock			69,459
Deemed Dividend	0	0	2,346	0
Series C Preferred Stock [Member] | Convertible Preferred Stock [Member]
Income (loss) per common share:
Repurchased and Retired During Period, Shares			34,800	33,896
Series C Cumulative Convertible Preferred Shares Repurchased and Retired	$ 229	$ 215	$ 229	$ 215