Consolidated Statements of Capital - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 599,332	$ 464,448	$ 413,599
Reversal of unrealized gains upon the sale of marketable securities	0	(32)	13
Cash flow hedge losses reclassified to earnings	3,338	1,824	0
Change in fair value of derivatives and amortization of swap settlements	(4,148)	(2,948)	7,824
Change in fair value of marketable securities, net	(61)	281	(118)
Issuance of common stock under:
Sale of common stock by general partner, net	(296)	72,539	(919)
Retirement of common stock, net	(269,315)	(56,989)	(51,233)
Changes in the redemption value of redeemable noncontrolling interest	4,299	(2,008)	(1,164)
Changes in noncontrolling interest from acquisition	1,349	65,472	7,919
Distributions to noncontrolling interest	(31,367)	(28,493)	(29,233)
Redemptions	(3,113)	$ (36,568)	$ (1,333)
ASU 2016-01
Issuance of common stock under:
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201601Member
ASU 2017-05
Issuance of common stock under:
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201705Member
ASU 2017-12
Issuance of common stock under:
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201712Member
Essex Portfolio, L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances	6,403,504	$ 6,393,844	$ 6,396,825
Net income	599,332	464,448	413,599
Reversal of unrealized gains upon the sale of marketable securities	0	(32)	13
Cash flow hedge losses reclassified to earnings	3,338	1,824	0
Change in fair value of derivatives and amortization of swap settlements	(4,148)	(2,948)	7,824
Change in fair value of marketable securities, net	(61)	281	(118)
Issuance of common stock under:
General partner's stock based compensation, net	9,201	33,779	6,213
Sale of common stock by general partner, net	(296)	72,539	(919)
Equity based compensation costs	12,913	12,283	12,851
Retirement of common stock, net	(269,315)	(56,989)	(51,233)
Cumulative effect upon adoption	6,403,504	6,403,504	6,393,844
Changes in the redemption value of redeemable noncontrolling interest	4,299	(2,008)	(1,164)
Changes in noncontrolling interest from acquisition	1,349	65,472	7,919
Distributions to noncontrolling interest	(12,292)	(10,521)	(12,174)
Redemptions	(3,113)	(36,568)	(1,333)
Distributions declared	(561,329)	(532,081)	(508,167)
Balances	6,183,192	6,403,504	6,393,844
Essex Portfolio, L.P. | Cumulative Effect, Period of Adoption, Adjustment | ASU 2017-05
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances			123,708
Issuance of common stock under:
Cumulative effect upon adoption			123,708
Essex Portfolio, L.P. | Cumulative Effect, Period of Adoption, Adjustment | ASU 2017-12
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances	(190)	181
Issuance of common stock under:
Cumulative effect upon adoption	(190)	(190)	181
Balances		(190)	181
Essex Portfolio, L.P. | Accumulated other comprehensive loss, net
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances	(10,432)	(9,738)	(15,229)
Reversal of unrealized gains upon the sale of marketable securities		(32)	13
Cash flow hedge losses reclassified to earnings	3,338	1,824
Change in fair value of derivatives and amortization of swap settlements	(4,148)	(2,948)	7,824
Change in fair value of marketable securities, net	(61)	281	(118)
Issuance of common stock under:
Cumulative effect upon adoption	(11,303)	(10,432)	(9,738)
Balances	(11,303)	(10,432)	(9,738)
Essex Portfolio, L.P. | Accumulated other comprehensive loss, net | Cumulative Effect, Period of Adoption, Adjustment | ASU 2016-01
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances			(2,228)
Issuance of common stock under:
Cumulative effect upon adoption			(2,228)
Essex Portfolio, L.P. | Accumulated other comprehensive loss, net | Cumulative Effect, Period of Adoption, Adjustment | ASU 2017-12
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances		181
Issuance of common stock under:
Cumulative effect upon adoption		181	181
Balances			181
Essex Portfolio, L.P. | Noncontrolling interest
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances	122,262	64,231	66,410
Net income	10,550	9,819	9,994
Issuance of common stock under:
Cumulative effect upon adoption	121,172	122,262	64,231
Changes in the redemption value of redeemable noncontrolling interest	121	1,310	68
Changes in noncontrolling interest from acquisition	1,349	65,472
Distributions to noncontrolling interest	(12,292)	(10,521)	(12,174)
Redemptions	(818)	(8,049)	(67)
Balances	121,172	122,262	64,231
Essex Portfolio, L.P. | General Partner | Common Equity
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances	$ 6,234,315	$ 6,280,290	$ 6,295,852
Balances (in shares)	66,092	65,890	66,054
Net income	$ 568,870	$ 439,286	$ 390,153
Issuance of common stock under:
General partner's stock based compensation, net	$ 9,201	$ 33,779	$ 6,213
General partner's stock based compensation, net (in shares)	95	195	41
Sale of common stock by general partner, net	$ (296)	$ 72,539	$ (919)
Sale of common stock by general partner, net (in shares)		228
Equity based compensation costs	12,453	$ 11,029	11,651
Retirement of common stock, net	$ (269,315)	$ (56,989)	$ (51,233)
Retirement of common stock, net (in shares)	(1,197)	(234)	(210)
Cumulative effect upon adoption	$ 6,015,139	$ 6,234,315	$ 6,280,290
Changes in the redemption value of redeemable noncontrolling interest	4,375	(3,427)	(1,143)
Redemptions	$ (2,020)	$ (28,083)	$ (1,061)
Redemptions (in shares)	9	13	5
Distributions declared	$ (542,254)	$ (514,109)	$ (491,108)
Balances	$ 6,015,139	$ 6,234,315	$ 6,280,290
Balances (in shares)	64,999	66,092	65,890
Essex Portfolio, L.P. | General Partner | Common Equity | ASU 2016-01
Issuance of common stock under:
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201601Member
Essex Portfolio, L.P. | General Partner | Common Equity | ASU 2017-05
Issuance of common stock under:
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201705Member
Essex Portfolio, L.P. | General Partner | Common Equity | ASU 2017-12
Issuance of common stock under:
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201712Member
Essex Portfolio, L.P. | General Partner | Common Equity | Cumulative Effect, Period of Adoption, Adjustment | ASU 2016-01
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances			$ 2,234
Issuance of common stock under:
Cumulative effect upon adoption			2,234
Essex Portfolio, L.P. | General Partner | Common Equity | Cumulative Effect, Period of Adoption, Adjustment | ASU 2017-05
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances			119,651
Issuance of common stock under:
Cumulative effect upon adoption			119,651
Essex Portfolio, L.P. | General Partner | Common Equity | Cumulative Effect, Period of Adoption, Adjustment | ASU 2017-12
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances	$ (190)
Issuance of common stock under:
Cumulative effect upon adoption	(190)	$ (190)
Balances		(190)
Essex Portfolio, L.P. | Limited Partner | Common Equity
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances	$ 57,359	$ 59,061	$ 49,792
Balances (in shares)	2,302	2,305	2,268
Net income	$ 19,912	$ 15,343	$ 13,452
Issuance of common stock under:
Equity based compensation costs	$ 460	$ 1,254	$ 1,200
Equity based compensation costs (in shares)	2	10	11
Cumulative effect upon adoption	$ 58,184	$ 57,359	$ 59,061
Changes in the redemption value of redeemable noncontrolling interest	(197)	109	(89)
Changes in noncontrolling interest from acquisition			$ 7,919
Changes in noncontrolling interest from acquisition (in shares)			31
Redemptions	$ (275)	$ (436)	$ (205)
Redemptions (in shares)	(9)	(13)	(5)
Distributions declared	$ (19,075)	$ (17,972)	$ (17,059)
Balances	$ 58,184	$ 57,359	$ 59,061
Balances (in shares)	2,295	2,302	2,305
Essex Portfolio, L.P. | Limited Partner | Common Equity | Cumulative Effect, Period of Adoption, Adjustment | ASU 2016-01
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances			$ (6)
Issuance of common stock under:
Cumulative effect upon adoption			(6)
Essex Portfolio, L.P. | Limited Partner | Common Equity | Cumulative Effect, Period of Adoption, Adjustment | ASU 2017-05
Increase (Decrease) in Partners' Capital [Roll Forward]
Balances			4,057
Issuance of common stock under:
Cumulative effect upon adoption			$ 4,057