Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Income Statements, Captions [Line Items]
Total property revenues									$ 1,460,155	$ 1,400,053	$ 1,363,899
Net income	$ 135,182	$ 105,700	$ 98,061	$ 125,505	$ 124,440	$ 86,110	$ 106,410	$ 96,639	464,448	413,599	458,043
Net income available to common stockholders	$ 128,818	$ 99,335	$ 92,275	$ 118,858	$ 117,820	$ 80,975	$ 100,440	$ 90,918	$ 439,286	$ 390,153	$ 433,059
Net income:
Net income available to common stockholders - basic (in dollars per share)	$ 1.95	$ 1.51	$ 1.40	$ 1.81	$ 1.78	$ 1.23	$ 1.52	$ 1.38	$ 6.67	$ 5.91	$ 6.58
Net income available to common stockholders - diluted (in dollars per share)	1.95	1.51	1.40	1.81	1.78	1.22	1.52	1.38	6.66	5.90	6.57
Dividends declared (in dollars per share)	$ 1.95	$ 1.95	$ 1.95	$ 1.95	$ 1.86	$ 1.86	$ 1.86	$ 1.86	$ 7.80	$ 7.44	$ 7.00
Essex Portfolio, L.P.
Condensed Income Statements, Captions [Line Items]
Total property revenues									$ 1,460,155	$ 1,400,053	$ 1,363,899
Net income	$ 135,182	$ 105,700	$ 98,061	$ 125,505	$ 124,440	$ 86,110	$ 106,410	$ 96,639	464,448	413,599	458,043
Net income available to common stockholders	$ 133,298	$ 102,799	$ 95,503	$ 123,029	$ 121,891	$ 83,764	$ 103,900	$ 94,050	$ 454,629	$ 403,605	$ 447,884
Net income:
Net income available to common stockholders - basic (in dollars per share)	$ 1.95	$ 1.51	$ 1.40	$ 1.81	$ 1.78	$ 1.23	$ 1.52	$ 1.38	$ 6.67	$ 5.91	$ 6.58
Net income available to common stockholders - diluted (in dollars per share)	1.95	1.51	1.40	1.81	1.78	1.23	1.52	1.38	$ 6.66	$ 5.90	$ 6.57
Dividends declared (in dollars per share)	$ 1.95	$ 1.95	$ 1.95	$ 1.95	$ 1.86	$ 1.86	$ 1.86	$ 1.86
Property
Condensed Income Statements, Captions [Line Items]
Total property revenues	$ 372,861	$ 364,504	$ 359,375	$ 353,888	$ 350,787	$ 348,610	$ 346,526	$ 344,947
Property | Essex Portfolio, L.P.
Condensed Income Statements, Captions [Line Items]
Total property revenues	$ 372,861	$ 364,504	$ 359,375	$ 353,888	$ 350,787	$ 348,610	$ 346,526	$ 344,947