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, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income	$ 962,501	$ 1,009,708	$ 685,192
Allocation to Noncontrolling Interests – Operating Partnership	(34,010)	(36,034)	(24,939)
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	(14,855)	(3,297)	(2,718)
Preferred distributions	(3,090)	(3,090)	(3,090)
Net income available to Common Shares	910,546	967,287	654,445
Numerator for net income per share – diluted	$ 944,556	$ 1,003,321	$ 679,384
Weighted average Common Shares outstanding	371,791	370,461	368,052
OP Units	13,003	12,907	12,869
Dilutive Securities Options	1,080	2,965	2,774
Denominator for net income per share – diluted	385,874	386,333	383,695
Net income per share – basic	$ 2.45	$ 2.61	$ 1.78
Net income per share – diluted	$ 2.45	$ 2.60	$ 1.77