Organization, Basis of Presentation, and Significant Accounting Policies - Earnings per Common Share (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) community $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares
Basic and diluted shares outstanding
Weighted average common shares - basic (in shares) | shares	139,389,433	140,094,722	139,054,191
Weighted average DownREIT units outstanding (in shares) | shares	7,500	7,500	7,500
Effect of dilutive securities (in shares) | shares	320,466	332,973	509,859
Weighted average common shares - diluted (in shares) | shares	139,717,399	140,435,195	139,571,550
Calculation of Earnings per Share—basic
Net income attributable to common stockholders	$ 1,004,299,000	$ 827,630,000	$ 785,974,000
Net income allocated to unvested restricted shares	(2,100,000)	(1,955,000)	(2,063,000)
Net income attributable to common stockholders, adjusted	$ 1,002,199,000	$ 825,675,000	$ 783,911,000
Weighted average common shares - basic (in shares) | shares	139,389,433	140,094,722	139,054,191
Earnings per common share - basic (in dollars per share) | $ / shares	$ 7.19	$ 5.89	$ 5.64
Calculation of Earnings per Share—diluted
Net income attributable to common stockholders	$ 1,004,299,000	$ 827,630,000	$ 785,974,000
Add: noncontrolling interests of DownREIT unitholders in consolidated partnerships, including discontinued operations	48,000	48,000	46,000
Adjusted net income attributable to common stockholders	$ 1,004,347,000	$ 827,678,000	$ 786,020,000
Weighted average common shares - diluted (in shares) | shares	139,717,399	140,435,195	139,571,550
Earnings per common share - diluted (in dollars per share) | $ / shares	$ 7.19	$ 5.89	$ 5.63
Casualty Loss, Abandoned Pursuit Costs and Impairment of Long-Lived Assets
Abandoned pursuits costs	$ 2,192,000	$ 12,317,000	$ 4,896,000
Casualty and impairment loss	3,119,000	0	0
Impairment of investment in unconsolidated entities	0	0	0
Impairment of long-lived assets held-for-use	$ 0	0	0
Number of communities held for sale | community	1
Uncollectible lease revenue	$ 52,075,000	66,763,000
New York City, NY
Casualty Loss, Abandoned Pursuit Costs and Impairment of Long-Lived Assets
Abandoned pursuits costs		7,264,000
East Coast | Hurricane and Fire
Casualty Loss, Abandoned Pursuit Costs and Impairment of Long-Lived Assets
Casualty and impairment loss	3,119,000
Land
Casualty Loss, Abandoned Pursuit Costs and Impairment of Long-Lived Assets
Casualty and impairment loss	$ 0	$ 0	$ 0