Reportable Segments - Reconciliation of NOI from Rental Real Estate Specific to Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Rental income	$ 598,059	$ 653,532	$ 1,195,661	$ 1,335,837
Property and maintenance expense	(107,746)	(104,452)	(224,800)	(220,268)
Real estate taxes and insurance expense	(97,401)	(95,038)	(200,871)	(192,770)
Operating income	376,844	356,889	512,404	778,974
Same Store, Non-same Store and Other
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]
Rental income	598,059	653,532	1,195,661	1,335,837
Property and maintenance expense	(107,746)	(104,452)	(224,800)	(220,268)
Real estate taxes and insurance expense	(97,401)	(95,038)	(200,871)	(192,770)
Total operating expenses	(205,147)	(199,490)	(425,671)	(413,038)
Operating income	$ 392,912	$ 454,042	$ 769,990	$ 922,799

The aggregate costs of keeping the property in good condition but that do not appreciably prolong the life or increase the value of the property.

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