Organization and Basis of Presentation - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) apartment investment community partnership building project shares	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) apartment investment community partnership building project shares	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) partnership community investment 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		$ 200		$ 800
Sales and maturities of marketable securities	2,100	$ 100	30,000	$ 14,900
Marketable securities, realized gain (loss)	$ 300	(100)	12,400	2,500
Unrealized gain (loss) on equity securities recognized through income			$ (46,441)	16,681
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	$ 917,900		$ 917,900		$ 909,300
Liabilities related to variable interest entities net of intercompany eliminations	319,200		319,200		320,100
Noncontrolling interest in variable interest entity	122,500		122,500		122,400
Fixed rate debt carrying amount	5,700,000		5,700,000		5,700,000
Fixed rate debt fair value	5,400,000		5,400,000		6,000,000
Variable rate debt, carrying amount	286,500		286,500		564,900
Variable rate debt fair value	284,600		284,600		561,700
Capitalized internal costs related to development and redevelopment projects	5,800	5,500	11,200	11,900
Redeemable noncontrolling interest	$ 33,213		$ 33,213		$ 34,666
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	$ (21,900)	$ 10,400	$ (46,400)	16,700
Essex Portfolio, L.P.
Real Estate Properties [Line Items]
Operating Partnership units outstanding (in shares) | shares	2,273,496		2,273,496		2,282,464
Redemption value of operating partnership units outstanding	$ 594,500		$ 594,500		$ 804,000
Unrealized gain (loss) on equity securities recognized through income			(46,441)	$ 16,681
Redeemable noncontrolling interest	$ 33,213		$ 33,213		$ 34,666
Partnership Interest
Real Estate Properties [Line Items]
Ownership interest in partnership	96.60%	96.60%	96.60%	96.60%