Condensed Consolidated Statement of Capital (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2015
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 50,542	$ 115,295
Change in fair value of derivatives and amortization of swap settlements		3,465
Change in fair value of marketable securities		(2,121)
Issuance of common stock under:
Sale of common stock by general partner		272,664
Reclassification of noncontrolling interest to redeemable noncontrolling interest		(144)
Distributions to noncontrolling interest		(11,589)
Redemptions		(2,488)
Essex Portfolio, L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		6,136,068
Net income	50,542	115,295
Change in fair value of derivatives and amortization of swap settlements		3,465
Change in fair value of marketable securities		(2,121)
Issuance of common stock under:
General partner's stock based compensation		19,882
Sale of common stock by general partner		272,664
Equity based compensation costs		1,921
Changes in redemption value of redeemable noncontrolling interest		(384)
Reclassification of noncontrolling interest to redeemable noncontrolling interest		(144)
Distributions to noncontrolling interest		(5,112)
Redemptions		(2,488)
Distributions declared		(194,406)
Balances	6,344,640	6,344,640
Essex Portfolio, L.P. [Member] \| Common Equity [Member] \| General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		$ 6,002,915
Balances (in shares)		63,683
Net income		$ 104,918
Issuance of common stock under:
General partner's stock based compensation		$ 18,346
General partner's stock based compensation (in shares)		140
Sale of common stock by general partner		$ 272,664
Sale of common stock by general partner (in shares)		1,220
Equity based compensation costs		$ 1,921
Changes in redemption value of redeemable noncontrolling interest		(384)
Redemptions		(2,083)
Distributions declared		(185,302)
Balances	$ 6,212,995	$ 6,212,995
Balances (in shares)	65,043	65,043
Essex Portfolio, L.P. [Member] \| Common Equity [Member] \| Limited Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		$ 48,665
Balances (in shares)		2,168
Net income		$ 3,644
Issuance of common stock under:
General partner's stock based compensation		$ 1,536
General partner's stock based compensation (in shares)		17
Redemptions		$ (405)
Redemptions (in shares)		(4)
Distributions declared		$ (6,477)
Balances	$ 46,963	$ 46,963
Balances (in shares)	2,181	2,181
Essex Portfolio, L.P. [Member] \| Preferred Equity [Member] \| General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		$ 71,209
Net income		2,627
Issuance of common stock under:
Distributions declared		(2,627)
Balances	$ 71,209	71,209
Essex Portfolio, L.P. [Member] \| Accumulated Other Comprehensive (Loss) Income [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		(49,356)
Change in fair value of derivatives and amortization of swap settlements		3,465
Change in fair value of marketable securities		(2,121)
Issuance of common stock under:
Balances	(48,012)	(48,012)
Essex Portfolio, L.P. [Member] \| Noncontrolling Interest [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		62,635
Net income		4,106
Issuance of common stock under:
Reclassification of noncontrolling interest to redeemable noncontrolling interest		(144)
Distributions to noncontrolling interest		(5,112)
Balances	$ 61,485	$ 61,485

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