Debt - Schedule of Debt and Lines of Credit (Details) $ in Thousands	1 Months Ended		9 Months Ended	12 Months Ended
	Oct. 31, 2025 USD ($)	May 31, 2025 USD ($) extensionOption	Sep. 30, 2025 USD ($) lineOfCredit	Dec. 31, 2024 USD ($) lineOfCredit	Jul. 31, 2025 USD ($)	Apr. 30, 2025 USD ($)	Feb. 28, 2025 USD ($)
Debt Instrument [Line Items]
Unsecured debt, net			$ 5,621,505	$ 5,473,788
Mortgage notes payable, net			795,404	989,884
Total debt, net			6,661,909	6,601,617
Debt instrument face amount			550,000
Long-term debt			6,448,334
Commercial Paper
Debt Instrument [Line Items]
Debt instrument, term		397 days
Essex Portfolio, L.P.
Debt Instrument [Line Items]
Unsecured debt, net			5,621,505	5,473,788
Mortgage notes payable, net			795,404	989,884
Interest Rate Swap
Debt Instrument [Line Items]
Derivative hedged item		$ 247,500
Interest rate		4.10%
Unsecured debt
Debt Instrument [Line Items]
Unsecured debt, net			5,621,505	5,473,788
Unsecured Term Loan 0.850%, Due May 2028
Debt Instrument [Line Items]
Number of extension options (in extensions) | extensionOption		2
Extension period		1 year
Commerical Paper Program | Commercial Paper
Debt Instrument [Line Items]
Debt instrument face amount			750,000
Unamortized debt issuance expense			$ 400
Debt instrument, term			397 days
Unsecured debt | Unsecured Term Loan 0.850%, Due May 2028
Debt Instrument [Line Items]
Debt instrument face amount		$ 300,000
Interest rate		0.85%
Long-term debt			$ 250,000
Unsecured debt | Unsecured Term Loan 0.850%, Due May 2028 | Maximum
Debt Instrument [Line Items]
Debt instrument face amount		$ 600,000
Unsecured debt | Unsecured Term Loan 0.850% Due January 2031 | Subsequent Event
Debt Instrument [Line Items]
Debt instrument face amount	$ 300,000
Interest rate	4.10%
Reduction in interest rate	0.10%
Basis spread on variable rate	0.85%
Unsecured debt | Unsecured Bonds 5.375%, Due April 2035 | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount							$ 400,000
Interest rate							5.375%
Debt instrument, debt offering price, percentage of principal							99.604%
Unsecured notes at maturity						$ 500,000
Unsecured debt | New Credit Facility | Lines of credit
Debt Instrument [Line Items]
Debt instrument face amount			$ 1,580,000	1,280,000
Interest rate					0.775%
Basis spread on variable rate			0.775%
Unamortized debt issuance expense			$ 7,400	$ 6,200
Numbers of line of credit | lineOfCredit			2	2
Aggregate borrowing capacity			$ 1,500,000		$ 1,200,000
Debt instrument, variable interest rate, type [extensible enumeration]			Secured Overnight Financing Rate (SOFR) [Member]
Unsecured debt | Working capital line of credit | Lines of credit
Debt Instrument [Line Items]
Basis spread on variable rate			0.775%
Aggregate borrowing capacity			$ 75,000
Term loan - variable rate, net
Debt Instrument [Line Items]
Weighted average interest rate			4.10%	4.20%
Term loan - variable rate, net | Unsecured debt
Debt Instrument [Line Items]
Term loan - variable rate, net			$ 547,545	$ 298,571
Weighted average maturity			3 years 2 months 12 days
Bonds public offering - fixed rate, net
Debt Instrument [Line Items]
Unamortized discount (premium), net			$ 700	(100)
Unamortized debt issuance expense			27,800	26,300
Bonds public offering - fixed rate, net | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Unsecured notes at maturity						$ 500,000
Bonds public offering - fixed rate, net | Unsecured debt
Debt Instrument [Line Items]
Unsecured debt, net			$ 5,073,960	5,175,217
Weighted average maturity			7 years 1 month 6 days
Bonds public offering - fixed rate, net | Unsecured Bonds 5.375%, Due April 2035 | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount							$ 400,000
Interest rate							5.375%
Debt instrument, debt offering price, percentage of principal							99.604%
Lines of credit
Debt Instrument [Line Items]
Lines of credit			$ 0	$ 137,945
Weighted average interest rate			5.20%	5.70%
Commercial Paper
Debt Instrument [Line Items]
Commercial paper			$ 245,000	$ 0
Weighted average interest rate			4.30%
Mortgage notes payable, net
Debt Instrument [Line Items]
Mortgage notes payable, net			$ 795,404	$ 989,884
Weighted average interest rate			4.20%	4.20%
Weighted average maturity			8 years 1 month 6 days
Unamortized discount (premium), net			$ 300	$ 200
Unamortized debt issuance expense			$ 2,700	$ 2,600
Weighted average interest rate on fixed rate unsecured bonds public offering
Debt Instrument [Line Items]
Weighted average interest rate			3.60%	3.40%