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	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 628,381	$ 4,479,586	$ 907,621
Income (Loss) Attributable to Noncontrolling Interest	(22,604)	(171,491)	(34,226)
Partially Owned Properties	(2,323)	(16,430)	(3,657)
Preferred distributions	(3,091)	(3,091)	(3,357)
Premium on redemption of Preferred Shares	0	0	(3,486)
Income from continuing operations available to Common Shares, net of Noncontrolling Interests	600,363	4,288,574	862,895
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0	498	382
Net income available to Common Shares	600,363	4,289,072	863,277
Income From Continuing Operations Available To Common Shares	622,967	4,460,065	897,121
Discontinued operations, net	0	518	397
Net Income (Loss) Available to Common Stockholders, Diluted	$ 622,967	$ 4,460,583	$ 897,518
Weighted average Common Shares outstanding	366,968	365,002	363,498
Dilutive Op Units	12,901	13,827	13,576
Dilutive Securities Options	2,809	3,163	3,546
Weighted average Common Shares outstanding	382,678	381,992	380,620
Net income available to Common Shares	$ 1.64	$ 11.75	$ 2.37
Net income available to Common Shares	1.63	11.68	2.36
Income from continuing operations available to Common Shares	1.64	11.75	2.37
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0	0	0
Earnings Per Share, Basic	1.64	11.75	2.37
Income from continuing operations available to Common Shares	1.63	11.68	2.36
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0	0	0
Earnings Per Share, Diluted	$ 1.63	$ 11.68	$ 2.36