Condensed Consolidated Statement of Capital (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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Change in fair value of marketable securities	1,934
Issuance of common stock under:
Sale of common stock by general partner	184,158
Reclassification Of Noncontrolling Interest To Redeemable Noncontrolling Interest	(144)
Changes in the redemption value of redeemable noncontrolling interest	(1,517)
Distributions to noncontrolling interest	(3,574)
Redemptions	(2,154)ess_RedemptionsOfNoncontrollingInterest
Essex Portfolio, L.P. [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances	6,136,068
Net income	64,753
Change in fair value of derivatives and amortization of swap settlements	(1,335)
Change in fair value of marketable securities	1,934
Issuance of common stock under:
General partner's stock based compensation	16,370
Sale of common stock by general partner	184,158
Equity based compensation costs	613
Reclassification Of Noncontrolling Interest To Redeemable Noncontrolling Interest	(144)
Changes in the redemption value of redeemable noncontrolling interest	(1,517)
Distributions to noncontrolling interest	(221)
Redemptions	(2,154)
Distributions declared	(97,669)
Balances	6,300,856
Essex Portfolio, L.P. [Member] \| Accumulated Other Comprehensive (Loss) Income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances	(49,356)
Change in fair value of derivatives and amortization of swap settlements	(1,335)
Issuance of common stock under:
Balances	(48,757)
Essex Portfolio, L.P. [Member] \| Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances	62,635
Net income	1,965
Issuance of common stock under:
Reclassification Of Noncontrolling Interest To Redeemable Noncontrolling Interest	(144)
Distributions to noncontrolling interest	(221)
Balances	64,235
Essex Portfolio, L.P. [Member] \| General Partner [Member] \| Common Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances	6,002,915
Balances (in shares)	63,683,000
Net income	59,363
Issuance of common stock under:
General partner's stock based compensation	15,613
General partner's stock based compensation (in shares)	115,000
Sale of common stock by general partner	184,158
Sale of common stock by general partner (in shares)	822,000
Equity based compensation costs	613
Changes in the redemption value of redeemable noncontrolling interest	(1,517)
Redemptions	(1,777)
Distributions declared	(93,002)
Balances	6,166,366
Balances (in shares)	64,620,000
Essex Portfolio, L.P. [Member] \| General Partner [Member] \| Preferred Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances	71,209
Net income	1,314
Issuance of common stock under:
Distributions declared	(1,314)
Balances	71,209
Essex Portfolio, L.P. [Member] \| Limited Partner [Member] \| Common Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balances	48,665
Balances (in shares)	2,168,000
Net income	2,111
Issuance of common stock under:
General partner's stock based compensation	757
General partner's stock based compensation (in shares)	17,000
Redemptions	(377)
Redemptions (in shares)	(2,000)
Distributions declared	(3,353)
Balances	$ 47,803
Balances (in shares)	2,183,000

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Change in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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