Consolidated Statements of Capital - USD ($) shares in Thousands, $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 204,517	$ 86,907	$ 85,762	$ 64,753	$ 438,410	$ 248,239	$ 134,438
Reversal of unrealized gains upon the sale of marketable securities					(4,848)	0	(886)
Changes in fair value of derivatives and amortization of swap settlements					15,926	7,893	4,168
Changes in fair value of marketable securities, net					(828)	1,865	6,302
Issuance of common stock under:
Sale of common stock by the general partner, net					(384)	332,137	532,670
Retirement of common stock, net					(1,045)
Reclassification of noncontrolling interest to redeemable noncontrolling interest						(19,772)	(20,890)
Changes in the redemption value of redeemable noncontrolling interest					768	(2,615)	312
Conversion of Series G preferred stock							4,349
Contributions from noncontrolling interest					0	0	1,419,816
Retirement of noncontrolling interest					0	0	(1,419,816)
Distributions to noncontrolling interests					(25,854)	(21,705)	(17,069)
Redemptions					(2,511)	(2,621)	(4,026)
Essex Portfolio, L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		6,337,023		6,136,068	6,337,023	6,136,068	1,998,238
Net income	204,517	86,907	85,762	64,753	438,410	248,239	134,438
Reversal of unrealized gains upon the sale of marketable securities					(4,848)	0	(886)
Changes in fair value of derivatives and amortization of swap settlements					15,926	7,893	4,168
Changes in fair value of marketable securities, net					(828)	1,865	6,302
Issuance of common stock under:
Common stock issued as consideration by general partner in merger							3,774,087
General partner's stock based compensation, net					18,949	26,540	11,024
Sale of common stock by the general partner, net					(384)	332,137	532,670
Equity-based compensation costs					10,899	9,646	11,872
Redemption of Series H preferred units					(73,750)
Retirement of common stock, net					(1,045)
Reclassification of noncontrolling interest to redeemable noncontrolling interest						(19,772)	(20,890)
Changes in the redemption value of redeemable noncontrolling interest					768	(2,615)	312
Conversion of Series G preferred stock							4,349
Contributions from noncontrolling interest					0	0	1,419,816
Retirement of noncontrolling interest					0	0	(1,419,816)
Distributions to noncontrolling interests					(11,296)	(8,751)	(4,890)
Redemptions					(2,511)	(2,621)	(5,497)
Distributions declared					(435,076)	(391,606)	(309,229)
Balances	6,292,237		6,337,023		6,292,237	6,337,023	6,136,068
Essex Portfolio, L.P. [Member] | Accumulated other comprehensive loss, net [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		(39,598)		(49,356)	(39,598)	(49,356)	(58,940)
Reversal of unrealized gains upon the sale of marketable securities					(4,848)		(886)
Changes in fair value of derivatives and amortization of swap settlements					15,926	7,893	4,168
Changes in fair value of marketable securities, net					(828)	1,865	6,302
Issuance of common stock under:
Balances	(29,348)		(39,598)		(29,348)	(39,598)	(49,356)
Essex Portfolio, L.P. [Member] | Noncontrolling Interest [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		49,642		62,635	49,642	62,635	66,130
Net income					9,342	8,295	7,421
Issuance of common stock under:
Reclassification of noncontrolling interest to redeemable noncontrolling interest						(12,115)	(5,084)
Changes in the redemption value of redeemable noncontrolling interest					596
Distributions to noncontrolling interests					(11,296)	(8,751)	(4,890)
Redemptions					(411)	(422)	(942)
Balances	47,873		49,642		47,873	49,642	62,635
Essex Portfolio, L.P. [Member] | General Partner [Member] | Common Equity [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		$ 6,208,535		$ 6,002,915	$ 6,208,535	$ 6,002,915	$ 1,873,882
Balances (in shares)		65,379		63,683	65,379	63,683	37,421
Net income					$ 411,124	$ 226,865	$ 116,859
Issuance of common stock under:
Common stock issued as consideration by general partner in merger							$ 3,774,087
Common stock issued as consideration by general partner in merger (in shares)							23,067
General partner's stock based compensation, net					$ 18,949	$ 26,540	$ 11,024
General partner's stock based compensation, net (in shares)					140	207	218
Sale of common stock by the general partner, net					$ (384)	$ 332,137	$ 532,670
Sale of common stock by the general partner, net (in shares)						1,482	2,943
Equity-based compensation costs					8,246	$ 5,946	$ 5,719
Retirement of common stock, net					$ (1,045)
Retirement of common stock, net (in shares)					(5)
Reclassification of noncontrolling interest to redeemable noncontrolling interest						(7,657)	(19,823)
Changes in the redemption value of redeemable noncontrolling interest					$ 172	(2,615)	312
Conversion of Series G preferred stock							$ 4,349
Conversion of Series G preferred stock (in shares)							34
Distributions to noncontrolling interests							$ 0
Redemptions					$ (2,117)	$ (2,199)	(3,374)
Redemptions (in shares)					(14)	(7)
Distributions declared					$ (419,204)	$ (373,397)	(292,790)
Balances	$ 6,224,276		$ 6,208,535		$ 6,224,276	$ 6,208,535	$ 6,002,915
Balances (in shares)	65,528		65,379		65,528	65,379	63,683
Essex Portfolio, L.P. [Member] | General Partner [Member] | Preferred Equity [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		$ 71,209		$ 71,209	$ 71,209	$ 71,209	$ 71,209
Net income					3,855	5,255	5,291
Issuance of common stock under:
Redemption of Series H preferred units					(73,750)
Distributions declared					(1,314)	(5,255)	(5,291)
Balances	$ 0		$ 71,209		0	71,209	71,209
Essex Portfolio, L.P. [Member] | Limited Partner [Member] | Common Equity [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		$ 47,235		$ 48,665	$ 47,235	$ 48,665	$ 45,957
Balances (in shares)		2,215		2,168	2,215	2,168	2,150
Net income					$ 14,089	$ 7,824	$ 4,867
Issuance of common stock under:
Equity-based compensation costs					$ 2,653	$ 3,700	$ 6,153
Equity-based compensation costs (in shares)					37	54	28
Reclassification of noncontrolling interest to redeemable noncontrolling interest						$ 0	$ 4,017
Reclassification of noncontrolling interest to redeemable noncontrolling interest (in shares)							(10)
Contributions from noncontrolling interest							$ 1,419,816
Contributions from noncontrolling interest (in shares)							8,561
Retirement of noncontrolling interest							$ (1,419,816)
Retirement of noncontrolling interest (in shares)							(8,561)
Distributions to noncontrolling interests							$ 0
Redemptions					$ 17	$ 0	(1,181)
Redemptions (in shares)					(15)	(7)
Distributions declared					$ (14,558)	$ (12,954)	(11,148)
Balances	$ 49,436		$ 47,235		$ 49,436	$ 47,235	$ 48,665
Balances (in shares)	2,237		2,215		2,237	2,215	2,168
Essex Portfolio, L.P. [Member] | Limited Partner [Member] | Preferred Equity [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		$ 0		$ 0	$ 0	$ 0	$ 0
Issuance of common stock under:
Balances	$ 0		$ 0		$ 0	$ 0	$ 0