Per Share and Per Unit Data (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Per Share And Per Unit Data
Net Income attributable to common stockholders or unitholders	$ 513,783	$ 504,744	$ 1,373,509	$ 1,441,128
Net Income attributable to Common Stockholders — Diluted	$ 513,783	$ 504,744	$ 1,373,509	$ 1,441,128
Weighted Average Shares Outstanding — Basic and Diluted	310,853,299	314,234,418	311,740,360	312,356,986
Operating Partnership
Per Share And Per Unit Data
Net Income attributable to common stockholders or unitholders	$ 591,872	$ 581,266	$ 1,581,864	$ 1,668,509
Net Income attributable to Common Stockholders — Diluted	$ 591,872	$ 581,266	$ 1,581,864	$ 1,668,509
Weighted Average Shares Outstanding — Basic and Diluted	358,115,572	361,764,112	359,029,893	361,640,742