Net Income Per Common Share and Net Income Per Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic:
Net income available to common stockholders	$ 411,124	$ 226,865	$ 116,859
Income from continuing operations available to common stockholders (in shares)	65,471,540	64,871,717	56,546,959
Income from continuing operations available to common stockholders (in dollars per share)	$ 6.28	$ 3.50	$ 2.07
Effect of Dilutive Securities	$ 0	$ 0	$ 0
Effect of Dilutive Securities (in shares)	116,276	189,968	149,566
Diluted:
Income from continuing operations available to common stockholders	$ 411,124	$ 226,865	$ 116,859
Income from continuing operations available to common stockholders (in shares)	65,587,816	65,061,685	56,696,525
Income from continuing operations available to common stockholders (in dollars per share)	$ 6.27	$ 3.49	$ 2.06
Convertible Limited Partnership Units [Member]
Diluted:
Anti-dilutive securities (in shares)	2,224,100	2,182,467	2,224,707
Antidilutive securities excluded from computation of earnings per share	$ 14,100	$ 7,800	$ 4,900
Stock Options [Member]
Diluted:
Anti-dilutive securities (in shares)	252,334	54,100	10,843
Essex Portfolio, L.P. [Member]
Basic:
Net income available to common stockholders	$ 425,213	$ 234,689	$ 121,726
Income from continuing operations available to common stockholders (in shares)	67,695,640	67,054,184	58,771,666
Income from continuing operations available to common stockholders (in dollars per share)	$ 6.28	$ 3.50	$ 2.07
Effect of Dilutive Securities	$ 0	$ 0	$ 0
Effect of Dilutive Securities (in shares)	116,276	189,968	149,566
Diluted:
Income from continuing operations available to common stockholders	$ 425,213	$ 234,689	$ 121,726
Income from continuing operations available to common stockholders (in shares)	67,811,916	67,244,152	58,921,232
Income from continuing operations available to common stockholders (in dollars per share)	$ 6.27	$ 3.49	$ 2.07