Significant Transactions During the Six Months Ended June 30, 2021 and Subsequent Events (Details)	1 Months Ended				3 Months Ended			6 Months Ended
	Jun. 30, 2021 USD ($) apartment	Mar. 31, 2021 USD ($)	Feb. 28, 2021 USD ($) apartment	Jan. 31, 2021 USD ($)	Jun. 30, 2021 USD ($) shares	Mar. 31, 2021 USD ($) shares	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Other Commitments [Line Items]
Gain on remeasurement of co-investment					$ 2,260,000		$ 0	$ 2,260,000	$ 234,694,000
Revenue from disposition					2,221,000		2,348,000	4,470,000	4,965,000
Commitments to acquire equity method investment				$ 20,000,000.0
Preferred return rate				10.00%
Notes receivable, early redemption fee received								4,747,000	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
Affiliated Entity | Related party bridge loan - Wesco I
Other Commitments [Line Items]
Notes receivable	52,800,000	$ 52,500,000			$ 52,800,000	$ 52,500,000		52,800,000
Interest rate		2.55%
Common Stock
Other Commitments [Line Items]
Shares repurchased during period (in shares) | shares					0	40,000
Shares repurchased during period, value						$ 9,200,000
Purchase authority remaining under stock repurchase plan	214,500,000				$ 214,500,000			214,500,000
Stock repurchase plan amount	250,000,000.0				250,000,000.0			250,000,000.0
Preferred Equity Investment Property In Southern California
Other Commitments [Line Items]
Proceeds from partial redemption of co-investment		$ 10,000,000.0
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					2,260,000		0	2,260,000	234,694,000
Revenue from disposition					2,221,000		$ 2,348,000	4,470,000	4,965,000
Notes receivable, early redemption fee received								4,747,000	$ 0
Essex Portfolio, L.P. | Senior Notes | 2028 Notes
Other Commitments [Line Items]
Debt issued		$ 450,000,000.0				$ 450,000,000.0
Debt coupon 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	$ 300,000,000.0				$ 300,000,000.0			$ 300,000,000.0
Debt coupon rate	2.55%				2.55%			2.55%
Debt offering price, percentage of par value	99.367%				99.367%			99.367%
Essex Portfolio, L.P. | Senior Notes | 2023 Notes
Other Commitments [Line Items]
Debt issued	$ 300,000,000.0				$ 300,000,000.0			$ 300,000,000.0
Debt coupon rate	3.375%				3.375%			3.375%
The Village at Toluca Lake | Joint Venture Partner, BEX III
Other Commitments [Line Items]
Investment interest acquired	50.00%
Payments to acquire real estate	$ 31,800,000
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
Hidden Valley, Simi Valley, CA
Other Commitments [Line Items]
Repayments of debt			$ 29,700,000
Revenue from disposition			105,000,000.0
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			$ 113,000,000.0
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