Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 30, 2017
Entity Information [Line Items]
Entity Registrant Name	ESSEX PROPERTY TRUST INC
Entity Central Index Key	0000920522
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		66,037,029
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Essex Portfolio, L.P. [Member]
Entity Information [Line Items]
Entity Registrant Name	ESSEX PORTFOLIO LP
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer