Earning Per Share and Earnings Per Unit - Computation of Net Income per Share Basic and Net Income per Share Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 144,196	$ 217,246	$ 498,297	$ 4,177,599
Allocation to Noncontrolling Interests – Operating Partnership, net	(5,166)	(8,344)	(17,931)	(160,437)
Net (income) attributable to Noncontrolling Interests – Partially Owned Properties	(801)	(823)	(2,354)	(2,368)
Preferred distributions	(772)	(773)	(2,318)	(2,318)
Income from continuing operations available to Common Shares, net of Noncontrolling Interests	137,457	207,306	475,694	4,012,476
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	237	0	119
Net income available to Common Shares	137,457	207,543	475,694	4,012,595
Income From Continuing Operations Available To Common Shares	142,623	215,650	493,625	4,172,913
Discontinued operations, net	0	246	0	124
Net Income (Loss) Available to Common Stockholders, Diluted	$ 142,623	$ 215,896	$ 493,625	$ 4,173,037
Weighted average Common Shares outstanding	366,996	365,109	366,809	364,917
Dilutive Op Units	12,910	13,899	12,907	13,828
Long-term compensation shares/units	3,039	3,365	2,924	3,539
Weighted average Common Shares outstanding	382,945	382,373	382,640	382,284
Net income available to Common Shares	$ 0.37	$ 0.57	$ 1.30	$ 11.00
Net income available to Common Shares	0.37	0.56	1.29	10.92
Income from continuing operations available to Common Shares	0.37	0.57	1.30	11.00
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0	0	0	0
Earnings Per Share, Basic	0.37	0.57	1.30	11.00
Income from continuing operations available to Common Shares	0.37	0.56	1.29	10.92
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0	0	0	0
Earnings Per Share, Diluted	$ 0.37	$ 0.56	$ 1.29	$ 10.92