Earnings (Loss) Per Common Share/Unit (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings per share reconciliation details
Net earnings (loss) attributable to common shares / unit holders	$ (45,459)	$ 55,436	$ (151,471)	$ (46,617)	$ (1,166,589)	$ (15,052)	$ (23,150)	$ (91,129)	(188,110)	$ (1,295,920)	$ (2,650)
Earnings (Loss) Per Common Share/Unit (Textual) [Abstract]
Total weighted average potentially dilutive share options and awards outstanding									7,648	4,498	5,151
Proportionate shares of acquired company shares issued									0.4464	0.4464	0.4464
REIT [Member]
Earnings per share reconciliation details
Net earnings (loss) attributable to common shares / unit holders									(188,110)	(1,295,920)	(2,650)
Weighted average common shares outstanding - Basic and Diluted	370,534				219,515				370,534	219,515	179,966
Net earnings (loss) per share attributable to common shares / unit holders - Basic and Diluted									0.51	$ (5.90)	$ (0.01)
Operating Partnership [Member]
Earnings per share reconciliation details
Net earnings (loss) attributable to common shares / unit holders									(188,459)	$ (1,295,920)	$ (2,650)
Weighted average common shares outstanding - Basic and Diluted	371,730				219,515				371,730	219,515	179,966
Net earnings (loss) per share attributable to common shares / unit holders - Basic and Diluted									(0.51)	$ (5.90)	$ (0.01)