Earnings 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, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 1,009,708	$ 685,192	$ 628,381
Allocation to Noncontrolling Interests – Operating Partnership	(36,034)	(24,939)	(22,604)
Partially Owned Properties	(3,297)	(2,718)	(2,323)
Preferred distributions	(3,090)	(3,090)	(3,091)
Net income available to Common Shares	967,287	654,445	600,363
Numerator for net income per share – diluted	$ 1,003,321	$ 679,384	$ 622,967
Weighted average Common Shares outstanding	370,461	368,052	366,968
OP Units	12,907	12,869	12,901
Dilutive Securities Options	2,965	2,774	2,809
Denominator for net income per share – diluted	386,333	383,695	382,678
Net income per share – basic	$ 2.61	$ 1.78	$ 1.64
Net income per share – diluted	$ 2.60	$ 1.77	$ 1.63