Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Income Statements, Captions [Line Items]
Total property revenues	$ 350,787	$ 348,610	$ 346,526	$ 344,947	$ 342,417	$ 341,974	$ 336,766	$ 333,168
Net income	124,440	86,110	106,410	96,639	109,662	85,035	75,795	187,551	$ 413,599	$ 458,043	$ 438,410
Net income available to common stockholders	$ 117,820	$ 80,975	$ 100,440	$ 90,918	$ 103,613	$ 79,723	$ 70,759	$ 178,964	$ 390,153	$ 433,059	$ 411,124
Net income:
Net income available to common stockholders - basic (in dollars per share)	$ 1.78	$ 1.23	$ 1.52	$ 1.38	$ 1.57	$ 1.21	$ 1.08	$ 2.73	$ 5.91	$ 6.58	$ 6.28
Net income available to common stockholders - diluted (in dollars per share)	1.78	1.22	1.52	1.38	1.57	1.21	1.08	2.72	5.90	6.57	6.27
Dividends declared (in dollars per share)	$ 1.86	$ 1.86	$ 1.86	$ 1.86	$ 1.75	$ 1.75	$ 1.75	$ 1.75	$ 7.44	$ 7.00	$ 6.40
Essex Portfolio, L.P. [Member]
Condensed Income Statements, Captions [Line Items]
Total property revenues	$ 350,787	$ 348,610	$ 346,526	$ 344,947	$ 342,417	$ 341,974	$ 336,766	$ 333,168
Net income	124,440	86,110	106,410	96,639	109,662	85,035	75,795	187,551	$ 413,599	$ 458,043	$ 438,410
Net income available to common stockholders	$ 121,891	$ 83,764	$ 103,900	$ 94,050	$ 107,149	$ 82,444	$ 73,181	$ 185,110	$ 403,605	$ 447,884	$ 425,213
Net income:
Net income available to common stockholders - basic (in dollars per share)	$ 1.78	$ 1.23	$ 1.52	$ 1.38	$ 1.57	$ 1.21	$ 1.08	$ 2.73	$ 5.91	$ 6.58	$ 6.28
Net income available to common stockholders - diluted (in dollars per share)	1.78	1.23	1.52	1.38	1.57	1.21	1.08	2.72	$ 5.90	$ 6.57	$ 6.27
Dividends declared (in dollars per share)	$ 1.86	$ 1.86	$ 1.86	$ 1.86	$ 1.75	$ 1.75	$ 1.75	$ 1.75