Organization and Basis of Presentation - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($) investment partnership building community apartment project shares	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) investment partnership building community apartment project shares	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) investment partnership community shares
Real Estate Properties [Line Items]
Apartment communities owned (in communities) | community	253		253
Apartment units owned (in apartments) | apartment	62,397		62,397
Ownership interest, number of commercial buildings (in commercial buildings) | building	3		3
Ownership interest, number of unconsolidated joint venture projects (in projects) | project	1		1
Equity securities	$ 200,000		$ 200,000		$ 800,000
Sales and maturities of marketable securities	0	$ 100,000	30,000,000	$ 15,000,000
Marketable securities, realized gain (loss)	$ 0	0	12,400,000	2,500,000
Unrealized gain (loss) on equity securities recognized through income			$ (63,556,000)	23,772,000
DownREIT limited partnerships consolidated by company (in partnerships) | partnership	18		18		18
Communities within DownREIT partnerships (in communities) | community	9		9		9
Number of previously consolidated co-investments considered VIE (in investments) | investment	6		6		6
Assets related to variable interest entities net of intercompany eliminations	$ 938,400,000		$ 938,400,000		$ 909,300,000
Liabilities related to variable interest entities net of intercompany eliminations	327,700,000		327,700,000		320,100,000
Noncontrolling interest in variable interest entity	122,100,000		122,100,000		122,400,000
Fixed rate debt carrying amount	5,700,000,000		5,700,000,000		5,700,000,000
Fixed rate debt fair value	5,200,000,000		5,200,000,000		6,000,000,000
Variable rate debt, carrying amount	442,600,000		442,600,000		564,900,000
Variable rate debt fair value	439,900,000		439,900,000		561,700,000
Capitalized internal costs related to development and redevelopment projects	4,500,000	5,600,000	15,700,000	17,500,000
Redeemable noncontrolling interest	$ 29,238,000		$ 29,238,000		$ 34,666,000
Minimum
Real Estate Properties [Line Items]
Apartment lease term	9 months		9 months
Maximum
Real Estate Properties [Line Items]
Apartment lease term	12 months		12 months
Interest And Other Income (Expense)
Real Estate Properties [Line Items]
Unrealized gain (loss) on equity securities recognized through income	$ (17,100,000)	$ 7,100,000	$ (63,600,000)	23,800,000
Essex Portfolio, L.P.
Real Estate Properties [Line Items]
Operating Partnership units outstanding (in shares) | shares	2,272,496		2,272,496		2,282,464
Redemption value of operating partnership units outstanding	$ 550,500,000		$ 550,500,000		$ 804,000,000
Unrealized gain (loss) on equity securities recognized through income			(63,556,000)	$ 23,772,000
Redeemable noncontrolling interest	$ 29,238,000		$ 29,238,000		$ 34,666,000
Partnership Interest
Real Estate Properties [Line Items]
Ownership interest in partnership	96.60%	96.60%	96.60%	96.60%