Earnings Per Share and Earnings Per Unit - Computation of Net Income per Unit Basic and Net Income per Unit Diluted for Operating Partnership (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net income	$ 328,040	$ 271,481	$ 388,404	$ 604,152
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	$ (741)	$ (880)	$ (1,423)	$ (13,410)
Dilutive Securities Options	1,964	1,095	1,773	1,570
Denominator for net income per share – diluted	387,820	385,913	387,367	386,272
Net income per Unit – basic	$ 0.84	$ 0.70	$ 1.00	$ 1.53
Net income per Unit – diluted	$ 0.84	$ 0.70	$ 1.00	$ 1.53
ERPOP [Member]
Net income	$ 328,040	$ 271,481	$ 388,404	$ 604,152
Net (income) loss attributable to Noncontrolling Interests – Partially Owned Properties	(741)	(880)	(1,423)	(13,410)
Allocation to Preference Units	(772)	(772)	(1,545)	(1,545)
Numerator for net income per Unit – basic and diluted	$ 326,527	$ 269,829	$ 385,436	$ 589,197
Denominator for net income per Unit – basic	385,856	384,818	385,594	384,702
Dilutive Securities Options	1,964	1,095	1,773	1,570
Denominator for net income per share – diluted	387,820	385,913	387,367	386,272
Net income per Unit – basic	$ 0.84	$ 0.70	$ 1.00	$ 1.53
Net income per Unit – diluted	$ 0.84	$ 0.70	$ 1.00	$ 1.53