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, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic:
Net income available to common stockholders/unitholders	$ 64,846	$ 84,458	$ 233,290	$ 399,464
Weighted average common shares/units (in shares)	65,001,677	65,412,407	64,995,682	65,728,119
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.00	$ 1.29	$ 3.59	$ 6.08
Effect of Dilutive Securities:
Stock options (in shares)	79,069	15,528	52,334	32,981
DownREIT units (in shares)			0	94,247
Diluted:
Net income available to common stockholders/unitholders	$ 64,846	$ 84,458	$ 233,290	$ 399,856
Weighted average common shares/units (in shares)	65,080,746	65,427,935	65,048,016	65,855,347
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.00	$ 1.29	$ 3.59	$ 6.07
Essex Portfolio, L.P.
Basic:
Net income available to common stockholders/unitholders	$ 67,134	$ 87,422	$ 241,525	$ 413,414
Weighted average common shares/units (in shares)	67,295,437	67,708,157	67,289,464	68,026,084
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.00	$ 1.29	$ 3.59	$ 6.08
Effect of Dilutive Securities:
Stock options (in shares)	79,069	15,528	52,334	32,981
DownREIT units (in shares)			0	94,247
Diluted:
Net income available to common stockholders/unitholders	$ 67,134	$ 87,422	$ 241,525	$ 413,806
Weighted average common shares/units (in shares)	67,374,506	67,723,685	67,341,798	68,153,312
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.00	$ 1.29	$ 3.59	$ 6.07
Convertible units
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	2,293,760	2,295,750	2,293,782	2,297,966
Income allocated to convertible OP Units	$ 2,300	$ 3,000	$ 8,200	$ 14,000
Stock options
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	136,172	431,253	0	290,570
Stock options | Essex Portfolio, L.P.
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	136,172	431,253	0	290,570
Subsidiaries | DownREIT Units
Effect of Dilutive Securities:
Income effect of Dilutive Securities			$ 0	$ 392
Subsidiaries | DownREIT Units | Essex Portfolio, L.P.
Effect of Dilutive Securities:
Income effect of Dilutive Securities			$ 0	$ 392