Net Income Per Common Share and Net Income Per Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic:
Net income available to common stockholders/unitholders	$ 84,458	$ 92,275	$ 399,464	$ 211,133
Weighted average common shares/units (in shares)	65,412,407	65,718,806	65,728,119	65,710,842
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.29	$ 1.40	$ 6.08	$ 3.21
Effect of Dilutive Securities:
Stock options (in shares)	15,528	103,009	32,981	91,575
DownREIT units (in shares)			94,247	0
Diluted:
Net income available to common stockholders/unitholders	$ 84,458	$ 92,275	$ 399,856	$ 211,133
Weighted average common shares/units (in shares)	65,427,935	65,821,815	65,855,347	65,802,417
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.29	$ 1.40	$ 6.07	$ 3.21
Essex Portfolio, L.P.
Basic:
Net income available to common stockholders/unitholders	$ 87,422	$ 95,503	$ 413,414	$ 218,532
Weighted average common shares/units (in shares)	67,708,157	68,018,090	68,026,084	68,012,999
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.29	$ 1.40	$ 6.08	$ 3.21
Effect of Dilutive Securities:
Stock options (in shares)	15,528	103,009	32,981	91,575
DownREIT units (in shares)			94,247	0
Diluted:
Net income available to common stockholders/unitholders	$ 87,422	$ 95,503	$ 413,806	$ 218,532
Weighted average common shares/units (in shares)	67,723,685	68,121,099	68,153,312	68,104,574
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.29	$ 1.40	$ 6.07	$ 3.21
Convertible units
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	2,295,750	2,299,284	2,297,966	2,302,158
Income allocated to convertible OP Units	$ 3,000	$ 3,200	$ 14,000	$ 7,400
Stock options
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	431,253	0	290,570	106,029
Stock options | Essex Portfolio, L.P.
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	431,253	0
Subsidiaries | DownREIT Units
Effect of Dilutive Securities:
Income effect of Dilutive Securities			$ 392	$ 0
Subsidiaries | DownREIT Units | Essex Portfolio, L.P.
Effect of Dilutive Securities:
Income effect of Dilutive Securities			$ 392	$ 0