Net Income Per Common Share and Net Income Per Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic [Abstract]
Income from discontinued operations available to common stockholders	$ 65,561	$ 42,323	$ 215,555	$ 147,241
Weighted average number of shares outstanding during the period (in shares)	65,507,669	65,138,868	65,455,004	64,714,994
Net income available to common stockholders (in dollars per share)	$ 1.00	$ 0.65	$ 3.29	$ 2.28
Effect of dilutive securities	$ 0	$ 0	$ 0	$ 0
Effect of dilutive securities (in shares)	109,882	158,682	123,657	177,776
Diluted [Abstract]
Income from continuing operations available to common stockholders	$ 65,561	$ 42,323	$ 215,555	$ 147,241
Adjusted income from continuing operations available to common stockholders (in shares)	65,617,551	65,297,550	65,578,661	64,892,770
Net income available to common stockholders (in dollars per share)	$ 1.00	$ 0.65	$ 3.29	$ 2.27
Essex Portfolio, L.P. [Member]
Basic [Abstract]
Income from discontinued operations available to common stockholders	$ 67,784	$ 43,794	$ 223,012	$ 152,356
Weighted average number of shares outstanding during the period (in shares)	67,728,621	67,316,498	67,679,240	66,896,293
Net income available to common stockholders (in dollars per share)	$ 1.00	$ 0.65	$ 3.30	$ 2.28
Effect of dilutive securities	$ 0	$ 0	$ 0	$ 0
Effect of dilutive securities (in shares)	109,882	158,682	123,657	177,776
Diluted [Abstract]
Income from continuing operations available to common stockholders	$ 67,784	$ 43,794	$ 223,012	$ 152,356
Adjusted income from continuing operations available to common stockholders (in shares)	67,838,503	67,475,180	67,802,897	67,074,069
Net income available to common stockholders (in dollars per share)	$ 1.00	$ 0.65	$ 3.29	$ 2.27
Convertible Limited Partnership Units [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	2,220,952	2,177,630	2,224,236	2,181,299
Antidilutive securities excluded from computation of earnings per share, value	$ 2,200	$ 1,500	$ 7,500	$ 5,100
Employee Stock Option [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	40,900	24,500	76,054	24,500
Employee Stock Option [Member] | Essex Portfolio, L.P. [Member]
Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	40,900	24,500	76,054	24,500