Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	$ 102,307	$ (58,511)	$ 183,987	$ (223,850)
Income (Loss) Attributable to Noncontrolling Interest	(4,422)	2,231	(7,475)	9,078
Net gain on sales of real estate properties	14,903	0	14,903	0
Allocation Of Net Income Loss To Noncontrolling Interests Partially Owned Properties	(588)	815	(1,092)	790
Dividends, Preferred Stock	(1,036)	(1,036)	(2,072)	(2,072)
Income (Loss) from Continuing Operations Attributable to Parent	111,164	(56,501)	188,251	(216,054)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	490	380,224	1,502	1,556,427
Net Income Loss Available To Common Stockholder Basic	111,654	323,723	189,753	1,340,373
Income From Continuing Operations Available To Common Shares	115,586		195,726
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	510	395,243	1,562	1,621,616
Net Income (Loss) Available to Common Stockholders, Diluted	116,096	323,723	197,288	1,340,373
Weighted Average Number of Shares Outstanding, Basic	360,809	359,653	360,641	348,654
Dilutive Op Units	13,742		13,736
Dilutive Securities Options	2,567		2,403
Weighted Average Number of Shares Outstanding, Diluted	377,118	359,653	376,780	348,654
Earnings Per Share, Basic	$ 0.309	$ 0.900	$ 0.526	$ 3.844
Earnings Per Share, Diluted	$ 0.308	$ 0.900	$ 0.524	$ 3.844
Income (loss) from continuing operations available to Common Shares	$ 0.308	$ (0.157)	$ 0.522	$ (0.620)
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share	$ 0.001	$ 1.057	$ 0.004	$ 4.464
Income (loss) from continuing operations available to Common Shares	$ 0.307	$ (0.157)	$ 0.520	$ (0.620)
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$ 0.001	$ 1.057	$ 0.004	$ 4.464
OPERATING PARTNERSHIP
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	102,307	(58,511)	183,987	(223,850)
Net gain on sales of real estate properties	14,903	0	14,903	0
Allocation Of Net Income Loss To Noncontrolling Interests Partially Owned Properties	(588)	815	(1,092)	790
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	510	395,243	1,562	1,621,616
Dilutive Securities Options	2,567		2,403
Earnings Per Share, Basic	$ 0.309	$ 0.900	$ 0.526	$ 3.844
Earnings Per Share, Diluted	$ 0.308	$ 0.900	$ 0.524	$ 3.844
Income (loss) from continuing operations available to Common Shares	$ 0.308	$ (0.157)	$ 0.522	$ (0.620)
Income (loss) from continuing operations available to Common Shares	$ 0.307	$ (0.157)	$ 0.520	$ (0.620)
Dividend preference units	(1,036)	(1,036)	(2,072)	(2,072)
Income (Loss) From Continuing Operations Available To Units	115,586	(58,732)	195,726	(225,132)
Net Income loss available to Op unitholders basic diluted numerator	$ 116,096	$ 336,511	$ 197,288	$ 1,396,484
Weighted Average Limited Partnership and General Partnership Units Outstanding, Basic	374,551	373,403	374,377	362,390
Weighted Average Number Of Limited Partnership And General Partnership Unit Outstanding Diluted	377,118	373,403	376,780	362,390
Income (Loss) from Discontinued Operations, Net of Tax, Per Outstanding Limited Partnership and General Partnership Unit, Basic	$ 0.001	$ 1.057	$ 0.004	$ 4.464
Income Loss From Discontinued Operations Net Of Tax Per Outstanding Limited Partnership And General Partnership Diluted	$ 0.001	$ 1.057	$ 0.004	$ 4.464