Consolidated Statement Of Shareholders' Equity - USD ($) $ in Thousands	Total	downREIT OP units	5.417% Series 1 Cumulative Convertible Preferred Shares	Preferred Shares	Preferred Shares 5.417% Series 1 Cumulative Convertible Preferred Shares	Common Shares	Common Shares downREIT OP units	Common Shares 5.417% Series 1 Cumulative Convertible Preferred Shares	Additional Paid-in Capital	Additional Paid-in Capital downREIT OP units	Additional Paid-in Capital 5.417% Series 1 Cumulative Convertible Preferred Shares	Accumulated Dividends in Excess of Net Income	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest	Noncontrolling Interest downREIT OP units
Beginning balance (in shares) at Dec. 31, 2021				405,896		78,603,305
Beginning balance at Dec. 31, 2021	$ 2,663,148			$ 159,997		$ 790			$ 3,488,794			$ (1,066,932)	$ (2,047)	$ 82,546
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income, excluding amounts attributable to redeemable noncontrolling interests	272,668											269,798		2,870
Other comprehensive income - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	8,131												8,131
Dividends declared to common shareholders	(256,867)											(256,867)
Dividends declared to preferred shareholders	(6,026)											(6,026)
Distributions declared to noncontrolling interests, excluding amounts attributable to redeemable noncontrolling interests	(4,066)													(4,066)
Common shares issued, net (in shares)						2,500,569
Common shares issued, net	292,344					$ 25			292,319
Exercise of stock options (in shares)						366
Exercise of stock options	35								35
Shares issued under dividend reinvestment plan (in shares)						13,832
Shares issued under dividend reinvestment plan	1,584								1,584
Share-based compensation expense, net of forfeitures (in shares)						110,915
Share-based compensation expense, net of forfeitures	11,258					$ 2			11,256
Shares withheld for employee taxes (in shares)						(40,974)
Shares withheld for employee taxes	(4,886)								(4,886)
Conversion of preferred shares (in shares)					(7,018)
Conversion of preferred shares					$ (175)
Conversion of preferred shares (in shares)								1,675
Conversion of preferred shares			$ 0								$ 175
Conversion of downREIT OP units (in Shares)							14,598
Conversion of downREIT OP units		$ 0					$ 0			$ 1,385
Conversion of downREIT OP units															$ (1,385)
Deconsolidation of VIE	972													972
Adjustment to redeemable noncontrolling interests	3,585								3,585
Ending balance (in shares) at Sep. 30, 2022				398,878		81,204,286
Ending balance at Sep. 30, 2022	2,981,880			$ 159,822		$ 817			3,794,247			(1,060,027)	6,084	80,937
Beginning balance (in shares) at Jun. 30, 2022				398,878		80,896,804
Beginning balance at Jun. 30, 2022	2,876,427			$ 159,822		$ 813			3,758,161			(1,126,463)	3,550	80,544
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income, excluding amounts attributable to redeemable noncontrolling interests	157,000											156,138		862
Other comprehensive income - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	2,534												2,534
Dividends declared to common shareholders	(87,694)											(87,694)
Dividends declared to preferred shareholders	(2,008)											(2,008)
Distributions declared to noncontrolling interests, excluding amounts attributable to redeemable noncontrolling interests	(1,441)													(1,441)
Common shares issued, net (in shares)						296,872
Common shares issued, net	32,892					$ 3			32,889
Exercise of stock options (in shares)						366
Exercise of stock options	35								35
Shares issued under dividend reinvestment plan (in shares)						5,832
Shares issued under dividend reinvestment plan	573								573
Share-based compensation expense, net of forfeitures (in shares)						6,810
Share-based compensation expense, net of forfeitures	3,579					$ 1			3,578
Shares withheld for employee taxes (in shares)						(2,398)
Shares withheld for employee taxes	(248)								(248)
Deconsolidation of VIE	972													972
Adjustment to redeemable noncontrolling interests	(741)								(741)
Ending balance (in shares) at Sep. 30, 2022				398,878		81,204,286
Ending balance at Sep. 30, 2022	2,981,880			$ 159,822		$ 817			3,794,247			(1,060,027)	6,084	80,937
Beginning balance (in shares) at Dec. 31, 2022				398,878		81,342,959
Beginning balance at Dec. 31, 2022	3,034,015			$ 159,822		$ 818			3,821,801			(1,034,186)	5,757	80,003
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income, excluding amounts attributable to redeemable noncontrolling interests	175,091											172,882		2,209
Other comprehensive income - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	1,016												1,016
Dividends declared to common shareholders	(265,022)											(265,022)
Dividends declared to preferred shareholders	(6,024)											(6,024)
Distributions declared to noncontrolling interests, excluding amounts attributable to redeemable noncontrolling interests	(3,283)													(3,283)
Common shares issued, net (in shares)						152,141
Common shares issued, net	15,895					$ 2			15,893
Shares issued under dividend reinvestment plan (in shares)						14,398
Shares issued under dividend reinvestment plan	1,380								1,380
Share-based compensation expense, net of forfeitures (in shares)						145,156
Share-based compensation expense, net of forfeitures	11,868					$ 1			11,867
Shares withheld for employee taxes (in shares)						(45,615)
Shares withheld for employee taxes	(4,979)								(4,979)
Conversion of downREIT OP units (in Shares)							9,123
Conversion of downREIT OP units		0					$ 0			883
Conversion of downREIT OP units															(883)
Contributions from noncontrolling interests	1,092													1,092
Ending balance (in shares) at Sep. 30, 2023				398,878		81,618,162
Ending balance at Sep. 30, 2023	2,961,049			$ 159,822		$ 821			3,846,845			(1,132,350)	6,773	79,138
Beginning balance (in shares) at Jun. 30, 2023				398,878		81,515,511
Beginning balance at Jun. 30, 2023	2,980,431			$ 159,822		$ 820			3,832,983			(1,098,432)	5,496	79,742
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income, excluding amounts attributable to redeemable noncontrolling interests	57,575											57,048		527
Other comprehensive income - change in fair value of interest rate swaps, excluding portion attributable to redeemable noncontrolling interests	1,277												1,277
Dividends declared to common shareholders	(88,958)											(88,958)
Dividends declared to preferred shareholders	(2,008)											(2,008)
Distributions declared to noncontrolling interests, excluding amounts attributable to redeemable noncontrolling interests	(1,081)													(1,081)
Common shares issued, net (in shares)						95,045
Common shares issued, net	9,703					$ 1			9,702
Shares issued under dividend reinvestment plan (in shares)						4,767
Shares issued under dividend reinvestment plan	475								475
Share-based compensation expense, net of forfeitures (in shares)						3,922
Share-based compensation expense, net of forfeitures	3,738					$ 0			3,738
Shares withheld for employee taxes (in shares)						(2,683)
Shares withheld for employee taxes	(268)								(268)
Conversion of downREIT OP units (in Shares)							1,600
Conversion of downREIT OP units		$ 0					$ 0			$ 215
Conversion of downREIT OP units															$ (215)
Contributions from noncontrolling interests	165													165
Ending balance (in shares) at Sep. 30, 2023				398,878		81,618,162
Ending balance at Sep. 30, 2023	$ 2,961,049			$ 159,822		$ 821			$ 3,846,845			$ (1,132,350)	$ 6,773	$ 79,138