Net Income Per Common Share and Net Income Per Common Unit (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Basic [Abstract]
Income from continuing operations available to common stockholders	$ 21,912,000		$ 24,690,000
Income from continuing operations available to common stockholders (in shares)	37,685,073		37,003,925
Income from continuing operations available to common stockholders (in dollars per share)	$ 0.58		$ 0.67
Income from discontinued operations available to common stockholders	0		513,000
Income from discontinued operations available to common stockholders (in shares)	37,685,000		37,004,000
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.01
Income available to common stockholders	21,912,000		25,203,000
Income available to common stockholders (in dollars per share)	$ 0.58		$ 0.68
Effect of dilutive securities	0	[1]	0	[1]
Effect of dilutive securities (in shares)	281,000	[1]	88,000	[1]
Diluted [Abstract]
Income from continuing operations available to common stockholders	21,912,000		24,690,000
Adjusted income from continuing operations available to common stockholders (in shares)	37,931,000		37,092,000
Adjusted income from continuing operations available to common stockholders (in dollars per share)	$ 0.58		$ 0.67
Adjusted income from discontinued operations available to common stockholders	0		513,000
Adjusted income from discontinued operations available to common stockholders (in shares)	37,931,000		37,092,000
Adjusted income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.01
Total income (Diluted)	21,912,000		25,203,000
Total income per common share amount (in dollars per share)	$ 0.58		$ 0.68
Convertible Limited Partnership Units [Member]
Diluted [Abstract]
Anti-dilutive securities (in shares)	2,272,179		2,079,447
Net income (loss) allocated to Limited Partners	1,400,000		1,500,000
Stock Options [Member]
Diluted [Abstract]
Anti-dilutive securities (in shares)	164,442		260,513
Essex Portfolio, L.P. [Member]
Basic [Abstract]
Income from continuing operations available to common stockholders	23,329,000		26,162,000
Income from continuing operations available to common stockholders (in shares)	39,957,252		39,083,371
Income from continuing operations available to common stockholders (in dollars per share)	$ 0.58		$ 0.67
Income from discontinued operations available to common stockholders	0		542,000
Income from discontinued operations available to common stockholders (in shares)	39,957,000		39,083,000
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.01
Income available to common stockholders	23,329,000		26,704,000
Income available to common stockholders (in dollars per share)	$ 0.58		$ 0.68
Effect of dilutive securities	0	[2]	0	[2]
Effect of dilutive securities (in shares)	281,000	[2]	88,000	[2]
Diluted [Abstract]
Income from continuing operations available to common stockholders	23,329,000		26,162,000
Adjusted income from continuing operations available to common stockholders (in shares)	40,203,000		39,171,000
Adjusted income from continuing operations available to common stockholders (in dollars per share)	$ 0.58		$ 0.67
Adjusted income from discontinued operations available to common stockholders	0		542,000
Adjusted income from discontinued operations available to common stockholders (in shares)	40,203,000		39,171,000
Adjusted income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.01
Total income (Diluted)	$ 23,329,000		$ 26,704,000
Total income per common share amount (in dollars per share)	$ 0.58		$ 0.68
Essex Portfolio, L.P. [Member] | Stock Options [Member]
Diluted [Abstract]
Anti-dilutive securities (in shares)	164,442		260,513

[1] Weighted average convertible limited partnership units of 2,272,179 and 2,079,447 which include vested Series Z-1 incentive units, for the three months ended March 31, 2014, and 2013, respectively, were not included in the determination of diluted EPS because they were anti-dilutive. Income allocated to convertible limited partnership units, which includes vested Series Z-1 units, aggregating $1.4 million and $1.5 million for the three months ended March 31, 2014 and 2013, respectively, have been excluded from income available to common stockholders for the calculation of diluted income per common share since these units are excluded from the diluted weighted average common shares for the period as the effect was anti-dilutive. The Company has the ability to redeem DownREIT limited partnership units for cash and does not consider them to be potentially dilutive securities.

[2] The Operating Partnership has the ability to redeem DownREIT limited partnership units for cash and does not consider them to be potentially dilutive securities.