Net Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic [Abstract]
Income from discontinued operations available to common stockholders	$ 45,555	$ 1,207	$ 104,918	$ 23,119
Income from discontinued operations available to common stockholders (in shares)	64,810,184	61,884,963	64,499,545	49,857,233
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0.70	$ 0.02	$ 1.63	$ 0.46
Effect of dilutive securities	$ 0	$ 0	$ 0	$ 0
Effect of dilutive securities (in shares)	162,668	174,799	177,976	229,928
Diluted [Abstract]
Income from continuing operations available to common stockholders	$ 45,555	$ 1,207	$ 104,918	$ 23,119
Adjusted income from continuing operations available to common stockholders (in shares)	64,972,852	62,059,762	64,677,521	50,087,161
Adjusted income from continuing operations available to common stockholders (in dollars per share)	$ 0.70	$ 0.02	$ 1.62	$ 0.46
Essex Portfolio, L.P. [Member]
Basic [Abstract]
Income from discontinued operations available to common stockholders	$ 47,088	$ 1,416	$ 108,562	$ 24,745
Income from discontinued operations available to common stockholders (in shares)	66,992,209	64,058,505	66,682,708	52,127,261
Income from discontinued operations available to common stockholders (in dollars per share)	$ 0.70	$ 0.02	$ 1.63	$ 0.47
Effect of dilutive securities	$ 0	$ 0	$ 0	$ 0
Effect of dilutive securities (in shares)	162,668	174,799	177,976	229,928
Diluted [Abstract]
Income from continuing operations available to common stockholders	$ 47,088	$ 1,416	$ 108,562	$ 24,745
Adjusted income from continuing operations available to common stockholders (in shares)	67,154,877	64,233,304	66,860,684	52,357,189
Adjusted income from continuing operations available to common stockholders (in dollars per share)	$ 0.70	$ 0.02	$ 1.62	$ 0.47
Convertible Limited Partnership Units [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	2,182,025	2,173,542	2,183,163	2,270,029
Antidilutive securities excluded from computation of earnings per share, value	$ 1,600	$ 200	$ 3,600	$ 1,600
Convertible Limited Partnership Units [Member] | Essex Portfolio, L.P. [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	903,285	903,285	903,285	903,285
Employee Stock Option [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	24,500	36,956	24,500	53,244
Employee Stock Option [Member] | Essex Portfolio, L.P. [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	0	36,956	0	53,244