Net Income Per Common Share and Net Income Per Common Unit - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Convertible units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	2,256,415	2,280,379	2,275,327	2,266,054
Income allocated to convertible OP Units	$ 5.8	$ 4.2	$ 20.8	$ 17.1
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	250,512	197,474	253,903	327,048
Stock options \| Essex Portfolio, L.P.
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	250,512	197,474	253,903	327,048

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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-Topic 260
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 480
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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