Significant Transactions During The Six Months Ended June 30, 2020 and Subsequent Events (Details)	1 Months Ended					3 Months Ended			6 Months Ended
	Jul. 31, 2020 USD ($) apartment	Jun. 30, 2020 USD ($) community	Apr. 30, 2020 USD ($) extension	Mar. 31, 2020 USD ($)	Jan. 31, 2020 USD ($) community apartment	Jun. 30, 2020 USD ($) shares	Mar. 31, 2020 USD ($) investment shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) community apartment	Jun. 30, 2019 USD ($)	Feb. 29, 2020 USD ($)
Other Commitments [Line Items]
Gain on remeasurement of co-investment						$ 0		$ 0	$ 234,694,000	$ 31,535,000
Revenue from disposition						2,348,000		2,260,000	4,965,000	4,595,000
Number of preferred equity method investments | investment							2
Commitments to acquire equity method investment							$ 91,400,000
Preferred return rate							11.30%
Funding amount to commitment of investment in mezzanine loan									6,669,000	0
Senior Notes | 2032 Notes
Other Commitments [Line Items]
Debt issued		$ 150,000,000.0				$ 150,000,000.0			$ 150,000,000.0
Debt offering price, percentage of par value		105.66%				105.66%			105.66%
Reoffer yield percentage									2.093%
Unsecured Term Loan
Other Commitments [Line Items]
Debt issued			$ 200,000,000.0
Number of extension options (in extensions) | extension			2
Extension period			12 months
Common Stock
Other Commitments [Line Items]
Shares repurchased during period (in shares) | shares						87,988	776,261
Shares repurchased during period, value						$ 20,100,000	$ 176,300,000
Purchase authority remaining under stock repurchase plan		$ 229,900,000				229,900,000			$ 229,900,000
Stock repurchase plan amount		250,000,000.0				250,000,000.0			$ 250,000,000.0
CPPIB interest
Other Commitments [Line Items]
Investment interest acquired					45.00%
Value of property held by acquired investment					$ 1,000,000,000.0
Gain on remeasurement of co-investment					234,700,000
Promote income					6,500,000
Joint venture that holds property in Los Angeles, CA
Other Commitments [Line Items]
Proceeds from partial redemption of co-investment				$ 11,300,000
Early redemption fee				200,000
Property Located in Anaheim, California
Other Commitments [Line Items]
Proceeds from redemption of notes receivable					$ 16,900,000
Multifamily Development Communities in Los Angeles, California
Other Commitments [Line Items]
Notes receivable, commitment to fund, amount				$ 15,000,000.0			$ 15,000,000.0
Notes receivable, interest rate				10.50%			10.50%
Notes receivable, term of extension option				2 years
Multifamily Development Communities in Sacramento, California
Other Commitments [Line Items]
Notes receivable, commitment to fund, amount				$ 29,200,000			$ 29,200,000
Notes receivable, interest rate				11.00%			11.00%
Notes receivable, term of extension option				2 years
Funding amount to commitment of investment in mezzanine loan			$ 6,700,000
Apartment Building | CPPIB interest
Other Commitments [Line Items]
Number of communities held by acquired investment | community					6
Number of units held by acquired investment | apartment					2,020
Apartment Building | One South Market, Museum Park
Other Commitments [Line Items]
Number of communities held by acquired investment | community									1
Number of units held by acquired investment | apartment									126
Essex Portfolio, L.P.
Other Commitments [Line Items]
Gain on remeasurement of co-investment						0		0	$ 234,694,000	31,535,000
Revenue from disposition						$ 2,348,000		$ 2,260,000	4,965,000	4,595,000
Funding amount to commitment of investment in mezzanine loan									6,669,000	$ 0
Essex Portfolio, L.P. | Senior Notes | 2032 Notes
Other Commitments [Line Items]
Debt issued											$ 500,000,000.0
Debt coupon rate											2.65%
Debt offering price, percentage of par value											99.628%
Repayments of secured debt									$ 100,300,000
Affiliated Entity | Related party bridge loan - Wesco V
Other Commitments [Line Items]
Proceeds from redemption of notes receivable					$ 85,800,000
LIBOR | Unsecured Term Loan
Other Commitments [Line Items]
Basis spread on variable rate			1.20%
One South Market and Museum Park
Other Commitments [Line Items]
Revenue from disposition		232,000,000.0
Gain (loss) on sale of properties		$ 16,600,000
One South Market and Museum Park | Apartment Building
Other Commitments [Line Items]
Number of units sold | community		2
Subsequent Event | Apartment Building | Delano, Redmond, WA
Other Commitments [Line Items]
Number of units held by acquired investment | apartment	126
Subsequent Event | One South Market and Museum Park
Other Commitments [Line Items]
Revenue from disposition	$ 51,500,000