Condensed Consolidated Statement of Capital - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 78,842	$ 105,700	$ 497,683	$ 329,266
Reversal of unrealized gains upon the sale of marketable debt securities				(32)
Cash flow hedge losses reclassified to earnings			3,282
Change in fair value of derivatives and amortization of swap settlements	1,884	(12)	(6,119)	(6,366)
Change in fair value of marketable debt securities, net	92	(25)	(178)	203
Issuance of common stock under:
Sale of common stock by general partner, net	(95)	72,631	(228)	72,549
Retirement of common units, net	(26,586)		(222,990)	(56,989)
Changes in the redemption value of redeemable noncontrolling interest	2,522	(2,247)	6,691	(3,675)
Changes in noncontrolling interest from acquisition			1,349	65,472
Distributions to noncontrolling interest	(7,677)	(6,789)	(23,689)	(20,897)
Redemptions	(1,268)	(1)	$ (2,971)	$ (14,180)
Accounting standards update [Extensible List]			us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201712Member
Essex Portfolio, L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	6,352,881	6,345,116	$ 6,403,504	$ 6,393,844
Net income	78,842	105,700	497,683	329,266
Reversal of unrealized gains upon the sale of marketable debt securities				(32)
Cash flow hedge losses reclassified to earnings			3,282
Change in fair value of derivatives and amortization of swap settlements	1,884	(12)	(6,119)	(6,366)
Change in fair value of marketable debt securities, net	92	(25)	(178)	203
Issuance of common stock under:
General partner's stock based compensation, net		27,679	9,201	32,907
Sale of common stock by general partner, net	(95)	72,631	(228)	72,549
Equity based compensation costs	2,361	1,814	9,294	7,914
Retirement of common units, net	(26,586)		(222,990)	(56,989)
Cumulative effect upon adoption of ASU No. 2016-13	6,352,881	6,415,004	6,403,504	6,393,844
Changes in the redemption value of redeemable noncontrolling interest	2,522	(2,247)	6,691	(3,675)
Changes in noncontrolling interest from acquisition			1,349	65,472
Distributions to noncontrolling interest	(2,908)	(2,302)	(9,381)	(7,412)
Redemptions	(1,268)	(1)	(2,971)	(14,180)
Partners' capital account, distributions declared	(140,243)	(133,349)	(421,465)	(398,678)
Balance at period end	$ 6,267,482	$ 6,415,004	$ 6,267,482	$ 6,415,004
Distribution declared (in dollars per share)	$ 2.0775	$ 1.95	$ 6.2325	$ 5.85
Accounting standards update [Extensible List]			us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201712Member
Essex Portfolio, L.P. | Common Equity | General Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning (in shares)	65,331	65,727	66,092	65,890
Balance at period beginning	$ 6,184,784	$ 6,173,899	$ 6,234,315	$ 6,280,290
Net income	73,661	$ 99,335	$ 473,125	$ 310,468
Issuance of common stock under:
General partner's stock based compensation, net (in shares)		126	95	188
General partner's stock based compensation, net		$ 27,679	$ 9,201	$ 32,907
Sale of common stock by general partner, net (in shares)		228	0	228
Sale of common stock by general partner, net	(95)	$ 72,631	$ (228)	$ 72,549
Equity based compensation costs	$ 2,279	1,544	$ 8,956	$ 7,016
Retirement of common units, net (in shares)	(121)		(985)	(234)
Retirement of common units, net	$ (26,586)		$ (222,990)	$ (56,989)
Cumulative effect upon adoption of ASU No. 2016-13	6,099,797	6,244,128	6,234,315	6,280,290
Changes in the redemption value of redeemable noncontrolling interest	2,346	$ (2,309)	$ 6,888	$ (5,048)
Redemptions (in shares)		1	8	(10)
Redemptions	(1,118)	$ 211	$ (2,123)	$ (11,872)
Partners' capital account, distributions declared	$ (135,474)	$ (128,862)	$ (407,157)	$ (385,193)
Balance at period end (in shares)	65,210	66,082	65,210	66,082
Balance at period end	$ 6,099,797	$ 6,244,128	$ 6,099,797	$ 6,244,128
Essex Portfolio, L.P. | Common Equity | Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning (in shares)	2,296	2,299	2,302	2,305
Balance at period beginning	$ 61,437	$ 57,726	$ 57,359	$ 59,061
Net income	2,593	$ 3,464	$ 16,543	$ 10,863
Issuance of common stock under:
Equity based compensation costs (in shares)		0	2	3
Equity based compensation costs	82	$ 270	$ 338	$ 898
Cumulative effect upon adoption of ASU No. 2016-13	59,441	57,002	57,359	59,061
Changes in the redemption value of redeemable noncontrolling interest	98	$ 61	$ (318)	$ 63
Redemptions (in shares)		(1)	(8)	(10)
Redemptions	0	$ (32)	$ (173)	$ (398)
Partners' capital account, distributions declared	$ (4,769)	$ (4,487)	$ (14,308)	$ (13,485)
Balance at period end (in shares)	2,296	2,298	2,296	2,298
Balance at period end	$ 59,441	$ 57,002	$ 59,441	$ 57,002
Essex Portfolio, L.P. | Accumulated Other Comprehensive Loss
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	(15,423)	(15,715)	(10,432)	(9,738)
Reversal of unrealized gains upon the sale of marketable debt securities				(32)
Cash flow hedge losses reclassified to earnings			3,282
Change in fair value of derivatives and amortization of swap settlements	1,884	(12)	(6,119)	(6,366)
Change in fair value of marketable debt securities, net	92	(25)	(178)	203
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13	(13,447)	(15,752)	(13,447)	(15,752)
Balance at period end	(13,447)	(15,752)	(13,447)	(15,752)
Essex Portfolio, L.P. | Noncontrolling Interest
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	122,083	129,206	122,262	64,231
Net income	2,588	2,901	8,015	7,935
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13	121,691	129,626	121,691	129,626
Changes in the redemption value of redeemable noncontrolling interest	78	1	121	1,310
Changes in noncontrolling interest from acquisition			1,349	65,472
Distributions to noncontrolling interest	(2,908)	(2,302)	(9,381)	(7,412)
Redemptions	(150)	(180)	(675)	(1,910)
Balance at period end	$ 121,691	$ 129,626	121,691	129,626
Cumulative Effect, Period Of Adoption, Adjustment | Essex Portfolio, L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning			(190)	181
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13			(190)	181
Cumulative Effect, Period Of Adoption, Adjustment | Essex Portfolio, L.P. | Common Equity
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning			(190)	0
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13			$ (190)	0
Cumulative Effect, Period Of Adoption, Adjustment | Essex Portfolio, L.P. | Accumulated Other Comprehensive Loss
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning				181
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13				$ 181