Net Income Per Common Share and Net Income Per Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Basic [Abstract]
Income from discontinued operations available to common stockholders	$ 77,981	$ 59,363
Weighted average number of shares outstanding during the period (in shares)	65,405,654	64,185,455
Net income available to common stockholders (in dollars per share)	$ 1.19	$ 0.92
Effect of dilutive securities	$ 0	$ 0
Effect of dilutive securities (in shares)	151,985	209,225
Diluted [Abstract]
Income from continuing operations available to common stockholders	$ 77,981	$ 59,363
Adjusted income from continuing operations available to common stockholders (in shares)	65,557,639	64,394,680
Net income available to common stockholders (in dollars per share)	$ 1.19	$ 0.92
Essex Portfolio, L.P. [Member]
Basic [Abstract]
Income from discontinued operations available to common stockholders	$ 80,765	$ 61,426
Weighted average number of shares outstanding during the period (in shares)	67,633,519	66,369,769
Net income available to common stockholders (in dollars per share)	$ 1.19	$ 0.93
Effect of dilutive securities	$ 0	$ 0
Effect of dilutive securities (in shares)	151,985	209,225
Diluted [Abstract]
Income from continuing operations available to common stockholders	$ 80,765	$ 61,426
Adjusted income from continuing operations available to common stockholders (in shares)	67,785,504	66,578,994
Net income available to common stockholders (in dollars per share)	$ 1.19	$ 0.92
Convertible Limited Partnership Units [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	2,227,865	2,184,314
Antidilutive securities excluded from computation of earnings per share, value	$ 2,800	$ 2,100
Convertible Limited Partnership Units [Member] | Essex Portfolio, L.P. [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	958,972	958,972
Employee Stock Option [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	77,200	0
Employee Stock Option [Member] | Essex Portfolio, L.P. [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	77,200	0