Net Income Per Common Share and Net Income Per Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic:
Net income available to common stockholders/unitholders	$ 168,444	$ 315,006
Weighted average common shares/units (in shares)	64,989,620	66,043,831
Net income available to common stockholders/unitholders (in dollars per share)	$ 2.59	$ 4.77
Effect of Dilutive Securities:
Stock options (in shares)	31,066	57,337
DownREIT units (in shares)	94,247	94,247
Diluted:
Net income available to common stockholders/unitholders	$ 168,641	$ 315,202
Weighted average common shares/units (in shares)	65,114,933	66,195,415
Net income available to common stockholders/unitholders (in dollars per share)	$ 2.59	$ 4.76
Essex Portfolio, L.P.
Basic:
Net income available to common stockholders/unitholders	$ 174,391	$ 325,992
Weighted average common shares/units (in shares)	67,283,424	68,344,012
Net income available to common stockholders/unitholders (in dollars per share)	$ 2.59	$ 4.77
Effect of Dilutive Securities:
Stock options (in shares)	31,066	57,337
DownREIT units (in shares)	94,247	94,247
Diluted:
Net income available to common stockholders/unitholders	$ 174,588	$ 326,188
Weighted average common shares/units (in shares)	67,408,737	68,495,596
Net income available to common stockholders/unitholders (in dollars per share)	$ 2.59	$ 4.76
Convertible units
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	2,293,804	2,300,181
Income allocated to convertible OP Units	$ 5,900	$ 11,000
Stock options
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	349,252	116,380
Stock options | Essex Portfolio, L.P.
Diluted:
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	349,252	116,380
Subsidiaries | DownREIT Units
Effect of Dilutive Securities:
Income effect of Dilutive Securities	$ 197	$ 196
Subsidiaries | DownREIT Units | Essex Portfolio, L.P.
Effect of Dilutive Securities:
Income effect of Dilutive Securities	$ 197	$ 196