Net Income Per Common Share (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Basic [Abstract]
Income from continuing operations available to common stockholders	$ 4,989,000		$ 24,356,000		$ 26,901,000		$ 49,017,000
Income from continuing operations available to common stockholders (in shares)	61,884,963		37,292,720		49,857,233		37,149,120
Income from continuing operations available to common stockholders (in dollars per share)	$ 0.08		$ 0.65		$ 0.54		$ 1.32
Income from discontinued operations available to common stockholders	0		590,000		0		1,132,000
Income from discontinued operations available to common stockholders (in shares)	61,885,000		37,293,000		49,857,000		37,149,000
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.02		$ 0.00		$ 0.03
Income available to common stockholders	4,989,000		24,946,000		26,901,000		50,149,000
Income available to common stockholders (in dollars per share)	$ 0.08		$ 0.67		$ 0.54		$ 1.35
Effect of dilutive securities	0	[1]	0	[1]	0	[1]	0	[1]
Effect of dilutive securities (in shares)	175,000	[1]	98,000	[1]	230,000	[1]	93,000	[1]
Diluted [Abstract]
Income from continuing operations available to common stockholders	4,989,000		24,356,000		26,901,000	[1]	49,017,000	[1]
Adjusted income from continuing operations available to common stockholders (in shares)	62,060,000		37,391,000		50,087,000	[1]	37,242,000	[1]
Adjusted income from continuing operations available to common stockholders (in dollars per share)	$ 0.08		$ 0.65		$ 0.54	[1]	$ 1.32	[1]
Adjusted income from discontinued operations available to common stockholders	0		590,000		0		1,132,000
Adjusted income from discontinued operations available to common stockholders (in shares)	62,060,000		37,391,000		50,087,000		37,242,000
Adjusted income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.02		$ 0		$ 0.03
Total income (Diluted)	4,989,000		24,946,000		26,901,000		50,149,000
Total income per common share amount (in dollars per share)	$ 0.08		$ 0.67		$ 0.54		$ 1.35
Convertible Limited Partnership Units [Member]
Diluted [Abstract]
Anti-dilutive securities (in shares)	2,173,542		2,151,494
Net income (loss) allocated to Limited Partners	200,000		1,500,000		1,600,000		3,000,000
Stock Options [Member]
Diluted [Abstract]
Anti-dilutive securities (in shares)	36,956		260,513		53,244		41,557
Essex Portfolio, L.P. [Member]
Basic [Abstract]
Income from continuing operations available to common stockholders	5,198,000		25,903,000		28,527,000		52,065,000
Income from continuing operations available to common stockholders (in shares)	64,058,505		39,444,214		52,127,261		39,264,790
Income from continuing operations available to common stockholders (in dollars per share)	$ 0.08		$ 0.65		$ 0.54		$ 1.32
Income from discontinued operations available to common stockholders	0		590,000		0		1,132,000
Income from discontinued operations available to common stockholders (in shares)	64,058,000		39,444,000		52,127,000		39,265,000
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.02		$ 0		$ 0.03
Income available to common stockholders	5,198,000		26,493,000		28,527,000		53,197,000
Income available to common stockholders (in dollars per share)	$ 0.08		$ 0.67		$ 0.54		$ 1.35
Effect of dilutive securities	0	[2]	0	[2]	0	[2]	0	[2]
Effect of dilutive securities (in shares)	175,000	[2]	98,000	[2]	230,000	[2]	93,000	[2]
Diluted [Abstract]
Income from continuing operations available to common stockholders	5,198,000	[2]	25,903,000	[2]	28,527,000	[2]	52,065,000	[2]
Adjusted income from continuing operations available to common stockholders (in shares)	64,233,000	[2]	39,542,000	[2]	52,357,000	[2]	39,358,000	[2]
Adjusted income from continuing operations available to common stockholders (in dollars per share)	$ 0.08	[2]	$ 0.65	[2]	$ 0.54	[2]	$ 1.32	[2]
Adjusted income from discontinued operations available to common stockholders	0		590,000		0		1,132,000
Adjusted income from discontinued operations available to common stockholders (in shares)	64,233,000		39,542,000		52,357,000		39,358,000
Adjusted income from discontinued operations available to common stockholders (in dollars per share)	$ 0		$ 0.02		$ 0		$ 0.03
Total income (Diluted)	$ 5,198,000		$ 26,493,000		$ 28,527,000		$ 53,197,000
Total income per common share amount (in dollars per share)	$ 0.08		$ 0.67		$ 0.54		$ 1.35
Essex Portfolio, L.P. [Member] | Stock Options [Member]
Diluted [Abstract]
Anti-dilutive securities (in shares)	36,956		20,825		53,244		41,557

[1] Weighted average convertible limited partnership units of 2,173,542 and 2,151,494 which include vested Series Z-1 incentive units, for the three months ended June 30, 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 $0.2 million and $1.5 million for the three months ended June 30, 2014 and 2013, respectively, and $1.6 million and $3.0 million for the six months ended June 30, 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.