Condensed Consolidated Statement of Capital (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2019
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 69,615	$ 90,076	$ 246,564	$ 418,841
Cash flow hedge losses reclassified to earnings		3,282		3,282
Change in fair value of derivatives and amortization of swap settlements	472	779	4,879	(8,003)
Change in fair value of marketable debt securities, net	172	35	257	(270)
Issuance of common stock under:
Sale of common stock by general partner, net	(84)	(63)	(84)	(133)
Retirement of common units, net		(20,093)	(9,172)	(196,404)
Accounting standards update					us-gaap:AccountingStandardsUpdate201613Member
Changes in the redemption value of redeemable noncontrolling interest	(2,512)	(598)	(6,595)	4,169
Contributions from noncontrolling interest			1,900
Changes in noncontrolling interest from acquisition				1,349
Distributions to noncontrolling interest	(7,303)	(8,133)	(14,857)	(16,012)
Redemptions	(2,063)	(335)	(2,318)	(1,703)
Essex Portfolio, L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	6,210,931	6,417,949	6,183,192	6,403,504
Net income	69,615	90,076	246,564	418,841
Cash flow hedge losses reclassified to earnings		3,282		3,282
Change in fair value of derivatives and amortization of swap settlements	472	779	4,879	(8,003)
Change in fair value of marketable debt securities, net	172	35	257	(270)
Issuance of common stock under:
General partner's stock based compensation, net	574	536	(3,170)	9,201
Sale of common stock by general partner, net	(84)	(63)	(84)	(133)
Equity based compensation costs	2,785	5,235	7,867	6,933
Retirement of common units, net		(20,093)	(9,172)	(196,404)
Accounting standards update					us-gaap:AccountingStandardsUpdate201613Member
Cumulative effect upon adoption of ASU No. 2016-13	6,136,703	6,352,881	6,136,703	6,352,881	$ 6,403,504
Changes in the redemption value of redeemable noncontrolling interest	(2,512)	(598)	(6,595)	4,169
Contributions from noncontrolling interest	0		1,900
Changes in noncontrolling interest from acquisition				1,349
Distributions to noncontrolling interest	(2,508)	(3,366)	(5,268)	(6,473)
Redemptions	(2,063)	(335)	(2,318)	(1,703)
Partners' capital account, distributions declared	(140,679)	(140,556)	(281,349)	(281,222)
Balance at period end	$ 6,136,703	$ 6,352,881	$ 6,136,703	$ 6,352,881	6,403,504
Essex Portfolio, L.P. | Common Equity | General Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning (in shares)	64,999	65,412	64,999	66,092
Balance at period beginning	$ 6,035,566	$ 6,250,833	$ 6,015,139	$ 6,234,315
Net income	$ 64,846	$ 84,458	$ 233,290	$ 399,464
Issuance of common stock under:
General partner's stock based compensation, net (in shares)	5	6	44	95
General partner's stock based compensation, net	$ 574	$ 536	$ (3,170)	$ 9,201
Sale of common stock by general partner, net	(84)	(63)	(84)	(133)
Equity based compensation costs	2,571	$ 5,058	$ 7,599	$ 6,677
Retirement of common units, net (in shares)		(88)	(40)	(864)
Retirement of common units, net		$ (20,093)	$ (9,172)	$ (196,404)
Cumulative effect upon adoption of ASU No. 2016-13	5,963,223	6,184,784	5,963,223	6,184,784	$ 6,234,315
Changes in the redemption value of redeemable noncontrolling interest	$ (2,574)	$ (199)	$ (6,752)	$ 4,542
Redemptions (in shares)	0	1	1	8
Redemptions	$ (1,792)	$ 43	$ (1,867)	$ (1,005)
Partners' capital account, distributions declared	$ (135,884)	$ (135,789)	$ (271,760)	$ (271,683)
Balance at period end (in shares)	65,004	65,331	65,004	65,331	66,092
Balance at period end	$ 5,963,223	$ 6,184,784	$ 5,963,223	$ 6,184,784	$ 6,234,315
Essex Portfolio, L.P. | Common Equity | Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning (in shares)	2,294	2,296	2,295	2,302
Balance at period beginning	$ 59,328	$ 63,550	$ 58,184	$ 57,359
Net income	2,288	$ 2,964	8,235	$ 13,950
Issuance of common stock under:
Equity based compensation costs (in shares)		0		2
Equity based compensation costs	214	$ 177	268	$ 256
Cumulative effect upon adoption of ASU No. 2016-13	56,950	61,437	56,950	61,437	$ 57,359
Changes in the redemption value of redeemable noncontrolling interest	$ (85)	(398)	$ (12)	$ (416)
Redemptions (in shares)	0		(1)	(8)
Redemptions	$ 0	(89)	$ (136)	$ (173)
Partners' capital account, distributions declared	$ (4,795)	$ (4,767)	$ (9,589)	$ (9,539)
Balance at period end (in shares)	2,294	2,296	2,294	2,296	2,302
Balance at period end	$ 56,950	$ 61,437	$ 56,950	$ 61,437	$ 57,359
Essex Portfolio, L.P. | Accumulated Other Comprehensive Loss
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	(6,811)	(19,519)	(11,303)	(10,432)
Cash flow hedge losses reclassified to earnings		3,282		3,282
Change in fair value of derivatives and amortization of swap settlements	472	779	4,879	(8,003)
Change in fair value of marketable debt securities, net	172	35	257	(270)
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13	(6,167)	(15,423)	(6,167)	(15,423)	(10,432)
Balance at period end	(6,167)	(15,423)	(6,167)	(15,423)	(10,432)
Essex Portfolio, L.P. | Noncontrolling Interest
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	122,848	123,085	121,172	122,262
Net income	2,481	2,654	5,039	5,427
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13	122,697	122,083	122,697	122,083	122,262
Changes in the redemption value of redeemable noncontrolling interest	147	(1)	169	43
Contributions from noncontrolling interest	0		1,900
Changes in noncontrolling interest from acquisition				1,349
Distributions to noncontrolling interest	(2,508)	(3,366)	(5,268)	(6,473)
Redemptions	(271)	(289)	(315)	(525)
Balance at period end	$ 122,697	$ 122,083	$ 122,697	122,083	122,262
Essex Portfolio, L.P. | Cumulative Effect, Period Of Adoption, Adjustment
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning				(190)
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13					(190)
Balance at period end					(190)
Essex Portfolio, L.P. | Cumulative Effect, Period Of Adoption, Adjustment | Common Equity | General Partner
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning				$ (190)
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2016-13					(190)
Balance at period end					$ (190)