Organization and Basis of Presentation - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025 USD ($) community apartment building partnership project investment shares	Sep. 30, 2024 USD ($) community	Sep. 30, 2025 USD ($) community apartment building partnership project investment shares	Sep. 30, 2024 USD ($) lawsuit community	Dec. 31, 2024 USD ($) community investment partnership shares
Real Estate Properties [Line Items]
Apartment communities owned (in communities) | community	257		257
Apartment units owned (in apartments) | apartment	62,451		62,451
Ownership interest, number of commercial buildings (in commercial buildings) | building	2		2
Development pipeline consisting of consolidated project | project	1		1
Marketable securities (less than)	$ 100		$ 100		$ 100
DownREIT limited partnerships consolidated by company (in partnerships) | partnership	18		18		18
Communities within DownREIT partnerships (in communities) | community	10		10		9
Number of previously consolidated co-investments considered VIE (in investments) | investment	4		4		5
Assets related to variable interest entities net of intercompany eliminations	$ 952,800		$ 952,800		$ 893,000
Liabilities related to variable interest entities net of intercompany eliminations	246,300		246,300		319,100
Noncontrolling interest in variable interest entity	101,200		101,200		105,100
Fixed rate debt carrying amount	5,600,000		5,600,000		5,800,000
Fixed rate debt fair value	5,400,000		5,400,000		5,500,000
Variable rate debt, carrying amount	1,100,000		1,100,000		752,300
Variable rate debt fair value	1,000,000		1,000,000		749,400
Capitalized internal costs related to development and redevelopment projects	6,500	$ 4,600	18,800	$ 14,800
Redeemable noncontrolling interest	$ 29,746		$ 29,746		$ 30,849
Number of company settled lawsuits | lawsuit				2
Construction defects at communities | community		2		2
Gain contingencies from legal settlements				$ 42,500
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	2,256,414		2,256,414		2,331,251
Redemption value of operating partnership units outstanding	$ 604,000		$ 604,000		$ 665,400
Redeemable noncontrolling interest	$ 29,746		$ 29,746		$ 30,849
Partnership Interest
Real Estate Properties [Line Items]
Ownership interest in partnership			96.60%		96.50%