Organization and Basis of Presentation - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($) community partnership investment apartment building shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) community partnership investment apartment building shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) partnership investment community shares
Real Estate Properties [Line Items]
Apartment communities owned (in communities) | community	255		255
Apartment units owned (in apartments) | apartment	62,510		62,510
Ownership interest, number of commercial buildings (in commercial buildings) | building	2		2
Marketable securities	$ 100		$ 100		$ 100
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	$ 970,000		$ 970,000		$ 956,700
Liabilities related to variable interest entities net of intercompany eliminations	326,000		326,000		324,500
Noncontrolling interest in variable interest entity	120,100		120,100		121,100
Fixed rate debt carrying amount	5,800,000		5,800,000		5,700,000
Fixed rate debt fair value	5,600,000		5,600,000		5,300,000
Variable rate debt, carrying amount	527,700		527,700		520,000
Variable rate debt fair value	526,200		526,200		519,000
Capitalized internal costs related to development and redevelopment projects	4,600	$ 5,000	14,800	$ 14,400
Redeemable noncontrolling interest	$ 33,977		33,977		$ 32,205
Gain contingencies from legal settlements			$ 42,500	$ 7,700
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
Essex Portfolio, L.P.
Real Estate Properties [Line Items]
Operating partnership units outstanding (in shares) | shares	2,332,449		2,332,449		2,258,812
Redemption value of operating partnership units outstanding	$ 689,100		$ 689,100		$ 560,000
Redeemable noncontrolling interest	$ 33,977		$ 33,977		$ 32,205
Partnership Interest
Real Estate Properties [Line Items]
Ownership interest in partnership			96.50%		96.60%