Significant Transactions During the Nine Months Ended September 30, 2021 and Subsequent Events (Details)	1 Months Ended							3 Months Ended			6 Months Ended		9 Months Ended
	Oct. 27, 2021 USD ($) apartment	Sep. 30, 2021 USD ($) commercial_lease apartment	Aug. 31, 2021 USD ($) apartment	Jun. 30, 2021 USD ($) apartment	Mar. 31, 2021 USD ($)	Feb. 28, 2021 USD ($) apartment	Jan. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Mar. 31, 2021 USD ($) shares	Sep. 30, 2020 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2021 USD ($) shares	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Other Commitments [Line Items]
Gain on remeasurement of co-investment								$ 0		$ 0			$ 2,260,000	$ 234,694,000
Revenue from disposition								2,237,000		2,347,000			6,707,000	7,312,000
Co-investments		$ 1,052,824,000						1,052,824,000				$ 1,052,824,000	1,052,824,000		$ 1,018,010,000
Commitments to acquire equity method investment		$ 26,200,000	$ 11,000,000				$ 20,000,000
Preferred return rate		12.50%	11.50%				10.00%
Notes receivable, early redemption fee received													4,747,000	0
Shares repurchased during period (in shares) | shares												0
Note receivable, secured, bearing interest at 11.00%, due October 2023 (Originated April 2020)
Other Commitments [Line Items]
Proceeds from redemption of notes receivable				$ 36,500,000
Notes receivable, early redemption fee received				4,700,000
Mezzanine Loans | Forecast
Other Commitments [Line Items]
Receivable with imputed interest, face amount											$ 50,000,000
Receivable with imputed interest, effective yield (interest rate)											11.00%
Option to extend											2 years
Affiliated Entity | Related party bridge loan - Wesco VI
Other Commitments [Line Items]
Notes receivable		$ 29,200,000						29,200,000				$ 29,200,000	29,200,000
Interest rate		2.15%
Affiliated Entity | Related party bridge loan - Wesco I
Other Commitments [Line Items]
Notes receivable					$ 52,500,000				$ 52,500,000
Interest rate					2.55%
Common Stock
Other Commitments [Line Items]
Shares repurchased and retired during period (in shares) | shares									40,000
Shares repurchased and retired during period, value									$ 9,200,000
Purchase authority remaining under stock repurchase plan		$ 214,500,000						214,500,000				214,500,000	214,500,000
Stock repurchase plan amount		250,000,000						250,000,000				250,000,000	250,000,000
Commercial Property 7 South Linden, South San Francisco, CA
Other Commitments [Line Items]
Payments to acquire real estate		$ 33,500,000
Number of commercial leases | commercial_lease		2
Wesco VI, LLC
Other Commitments [Line Items]
Limited partnership interest in partnership investments		50.00%
Co-investments		$ 150,000,000						150,000,000				$ 150,000,000	150,000,000
Commercial Property Third & Broad, Seattle, WA
Other Commitments [Line Items]
Payments to acquire real estate		52,500,000
Preferred Equity Investment Property in Northern California
Other Commitments [Line Items]
Proceeds from partial redemption of co-investment			$ 21,600,000
Preferred Equity Investment Property in Southern California
Other Commitments [Line Items]
Proceeds from partial redemption of co-investment					$ 10,000,000
Joint Venture That Holds Property in Southern California
Other Commitments [Line Items]
Proceeds from partial redemption of co-investment					110,200,000
Early redemption fee					3,500,000
Essex Portfolio, L.P.
Other Commitments [Line Items]
Gain on remeasurement of co-investment								0		0			2,260,000	234,694,000
Revenue from disposition								$ 2,237,000		$ 2,347,000			6,707,000	7,312,000
Notes receivable, early redemption fee received													$ 4,747,000	$ 0
Essex Portfolio, L.P. | Senior Notes | 2028 Notes
Other Commitments [Line Items]
Debt issued					$ 450,000,000				$ 450,000,000
Interest rate					1.70%				1.70%
Debt offering price, percentage of par value					99.423%				99.423%
Essex Portfolio, L.P. | Senior Notes | 2031 Notes
Other Commitments [Line Items]
Debt issued				$ 300,000,000
Interest rate				2.55%
Debt offering price, percentage of par value				99.367%
Essex Portfolio, L.P. | Senior Notes | 2023 Notes
Other Commitments [Line Items]
Debt issued				$ 300,000,000
Interest rate				3.375%
The Village at Toluca Lake | Joint Venture Partner, BEX III
Other Commitments [Line Items]
Payments to acquire real estate				$ 31,800,000
Investment interest acquired				50.00%
Repayments of debt				$ 29,500,000
Gain on remeasurement of co-investment				$ 2,300,000
The Village at Toluca Lake | Apartment Building | Joint Venture Partner, BEX III
Other Commitments [Line Items]
Number of units acquired | apartment				145
Devonshire, Hemet, CA
Other Commitments [Line Items]
Revenue from disposition			54,500,000
Gain on sale of properties			$ 42,900,000
Devonshire, Hemet, CA | Apartment Building
Other Commitments [Line Items]
Number of apartment units | apartment			276
Hidden Valley, Simi Valley, CA
Other Commitments [Line Items]
Repayments of debt						$ 29,700,000
Revenue from disposition						105,000,000
Gain on sale of properties						$ 69,200,000
Hidden Valley, Simi Valley, CA | Apartment Building
Other Commitments [Line Items]
Number of apartment units | apartment						324
Park 20, San Mateo, CA
Other Commitments [Line Items]
Revenue from disposition						$ 113,000,000
Park 20, San Mateo, CA | Apartment Building
Other Commitments [Line Items]
Number of apartment units | apartment						197
Axis 2300, Irvine, CA
Other Commitments [Line Items]
Revenue from disposition						$ 57,500,000
Gain on sale of properties						$ 30,800,000
Axis 2300, Irvine, CA | Apartment Building
Other Commitments [Line Items]
Number of apartment units | apartment						115
Martha Lake Apartment | Wesco VI, LLC
Other Commitments [Line Items]
Payments to acquire real estate		$ 53,000,000
Martha Lake Apartment | Apartment Building | Wesco VI, LLC
Other Commitments [Line Items]
Number of units acquired | apartment		155
Monterra in Mill Creek | Wesco VI, LLC | Subsequent Event
Other Commitments [Line Items]
Payments to acquire real estate	$ 55,000,000
Monterra in Mill Creek | Apartment Building | Wesco VI, LLC | Subsequent Event
Other Commitments [Line Items]
Number of units acquired | apartment	139