Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements, Captions [Line Items]
Total property revenues	$ 326,905	$ 327,078	$ 319,562	$ 312,178	$ 308,646	$ 302,522	$ 294,101	$ 280,229	$ 1,285,723	$ 1,185,498	$ 961,591
Net income	204,517	70,162	76,824	86,907	85,762	47,182	50,542	64,753	438,410	248,239	134,438
Net income available to common stockholders	$ 195,569	$ 65,561	$ 72,013	$ 77,981	$ 79,624	$ 42,323	$ 45,555	$ 59,363	$ 411,124	$ 226,865	$ 116,859
Net income:
Net income available to common stockholders - basic (in dollars per share)	$ 2.98	$ 1.00	$ 1.10	$ 1.19	$ 1.22	$ 0.65	$ 0.70	$ 0.92	$ 6.28	$ 3.50	$ 2.07
Net income available to common stockholders - diluted (in dollars per share)	2.98	1.00	1.10	1.19	1.22	0.65	0.70	0.92	$ 6.27	$ 3.49	$ 2.06
Market price:
High (in dollars per share)	234.07	236.56	237.50	240.55	244.71	232.20	231.90	243.17
Low (in dollars per share)	200.01	217.16	207.20	191.25	214.29	205.72	208.85	207.26
Close (in dollars per share)	232.50	222.70	228.09	233.86	239.41	223.42	212.50	229.90
Dividends declared (in dollars per share)	$ 1.6	$ 1.60	$ 1.60	$ 1.60	$ 1.44	$ 1.44	$ 1.44	$ 1.44
Essex Portfolio, L.P. [Member]
Condensed Income Statements, Captions [Line Items]
Total property revenues	$ 326,905	$ 327,078	$ 319,562	$ 312,178	$ 308,646	$ 302,522	$ 294,101	$ 280,229	$ 1,285,723	$ 1,185,498	$ 961,591
Net income	204,517	70,162	76,824	86,907	85,762	47,182	50,542	64,753	438,410	248,239	134,438
Net income available to common stockholders	$ 202,201	$ 67,784	$ 74,463	$ 80,765	$ 82,333	$ 43,794	$ 47,088	$ 61,474	$ 425,213	$ 234,689	$ 121,726
Net income:
Net income available to common stockholders - basic (in dollars per share)	$ 2.98	$ 1.00	$ 1.10	$ 1.19	$ 1.22	$ 0.65	$ 0.70	$ 0.93	$ 6.28	$ 3.50	$ 2.07
Net income available to common stockholders - diluted (in dollars per share)	2.98	1.00	1.10	1.19	1.22	0.65	0.70	0.92	$ 6.27	$ 3.49	$ 2.07
Market price:
Dividends declared (in dollars per share)	$ 1.6	$ 1.6	$ 1.6	$ 1.6	$ 1.44	$ 1.44	$ 1.44	$ 1.44