Condensed Consolidated Statement of Capital - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Jan. 01, 2018
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 105,700	$ 86,110	$ 329,266	$ 289,159
Reversal of unrealized gains upon the sale of marketable debt securities		4	(32)	6
Change in fair value of marketable debt securities, net	(25)	12	203	(87)
Issuance of common stock under:
Sale of common stock by general partner, net	72,631	(130)	72,549	(483)
Retirement of common units, net			(56,989)	(3,774)
Changes in the redemption value of redeemable noncontrolling interest	(2,247)	(408)	(3,675)	(2,253)
Changes in noncontrolling interest from acquisition			65,472
Distributions to noncontrolling interest	(6,789)	(6,884)	(20,897)	(22,281)
Redemptions	(1)	(100)	(14,180)	(157)
ASU 2017-12 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12					$ 181
ASU 2016-01 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						$ 0
ASU 2017-05 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						123,708
Essex Portfolio, L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	6,345,116	6,474,683	6,393,844	6,396,825
Net income	105,700	86,110	329,266	289,159
Reversal of unrealized gains upon the sale of marketable debt securities		4	(32)	6
Change in fair value of derivatives and amortization of swap settlements	(12)	2,974	(6,366)	12,630
Change in fair value of marketable debt securities, net	(25)	12	203	(87)
Issuance of common stock under:
General partner's stock based compensation, net	27,679	887	32,907	2,751
Sale of common stock by general partner, net	72,631	(130)	72,549	(483)
Equity based compensation costs	1,814	1,747	7,914	8,561
Retirement of common units, net			(56,989)	(3,774)
Changes in the redemption value of redeemable noncontrolling interest	(2,247)	(408)	(3,675)	(2,253)
Changes in noncontrolling interest from acquisition			65,472
Distributions to noncontrolling interest	(2,302)	(2,632)	(7,412)	(9,522)
Redemptions	(1)	(100)	(14,180)	(157)
Distributions declared	(133,349)	(127,119)	(398,678)	(381,336)
Balance at period end	6,415,004	6,436,028	6,415,004	6,436,028
Essex Portfolio, L.P. [Member] | ASU 2017-12 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12					181
Essex Portfolio, L.P. [Member] | ASU 2016-01 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						0
Essex Portfolio, L.P. [Member] | ASU 2017-05 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						123,708
Essex Portfolio, L.P. [Member] | Common Equity [Member] | General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	$ 6,173,899	$ 6,365,623	$ 6,280,290	$ 6,295,852
Balance at period beginning (in shares)	65,727	66,050	65,890	66,054
Net income	$ 99,335	$ 80,975	$ 310,468	$ 272,333
Issuance of common stock under:
General partner's stock based compensation, net	$ 27,679	$ 887	$ 32,907	$ 2,751
General partner's stock based compensation, net (in shares)	126	5	188	17
Sale of common stock by general partner, net	$ 72,631	$ (130)	$ 72,549	$ (483)
Sale of common stock by general partner, net (in shares)	228		228
Equity based compensation costs	$ 1,544	1,496	$ 7,016	7,697
Retirement of common units, net			$ (56,989)	$ (3,774)
Retirement of common units, net (in shares)			(234)	(17)
Changes in the redemption value of redeemable noncontrolling interest	(2,309)	(386)	$ (5,048)	$ (2,032)
Redemptions	$ 211	(89)	$ (11,872)	$ (143)
Redemptions (in shares)	(1)		(10)	(1)
Distributions declared	$ (128,862)	(122,867)	$ (385,193)	$ (368,577)
Balance at period end	$ 6,244,128	$ 6,325,509	$ 6,244,128	$ 6,325,509
Balance at period end (in shares)	66,082	66,055	66,082	66,055
Essex Portfolio, L.P. [Member] | Common Equity [Member] | General Partner [Member] | ASU 2016-01 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						2,234
Essex Portfolio, L.P. [Member] | Common Equity [Member] | General Partner [Member] | ASU 2017-05 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						119,651
Essex Portfolio, L.P. [Member] | Common Equity [Member] | Limited Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	$ 57,726	$ 52,339	$ 59,061	$ 49,792
Balance at period beginning (in shares)	2,299	2,273	2,305	2,268
Net income	$ 3,464	$ 2,789	$ 10,863	$ 9,381
Issuance of common stock under:
Equity based compensation costs	270	251	$ 898	$ 864
Equity based compensation costs (in shares)			3	5
Changes in the redemption value of redeemable noncontrolling interest	61	(34)	$ 63	$ (233)
Redemptions	$ (32)		$ (398)	$ (3)
Redemptions (in shares)	(1)		(10)	0
Distributions declared	$ (4,487)	(4,252)	$ (13,485)	$ (12,759)
Balance at period end	$ 57,002	$ 51,093	$ 57,002	$ 51,093
Balance at period end (in shares)	2,298	2,273	2,298	2,273
Essex Portfolio, L.P. [Member] | Common Equity [Member] | Limited Partner [Member] | ASU 2016-01 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						(6)
Essex Portfolio, L.P. [Member] | Common Equity [Member] | Limited Partner [Member] | ASU 2017-05 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						4,057
Essex Portfolio, L.P. [Member] | Accumulated Other Comprehensive Loss [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	$ (15,715)	$ (7,898)	$ (9,738)	$ (15,229)
Reversal of unrealized gains upon the sale of marketable debt securities		4	(32)	6
Change in fair value of derivatives and amortization of swap settlements	(12)	2,974	(6,366)	12,630
Change in fair value of marketable debt securities, net	(25)	12	203	(87)
Issuance of common stock under:
Balance at period end	(15,752)	(4,908)	(15,752)	(4,908)
Essex Portfolio, L.P. [Member] | Accumulated Other Comprehensive Loss [Member] | ASU 2017-12 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12					$ 181
Essex Portfolio, L.P. [Member] | Accumulated Other Comprehensive Loss [Member] | ASU 2016-01 [Member]
Issuance of common stock under:
Cumulative effect upon adoption of ASU No. 2017-12						$ (2,228)
Essex Portfolio, L.P. [Member] | Noncontrolling Interest [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at period beginning	129,206	64,619	64,231	66,410
Net income	2,901	2,346	7,935	7,445
Issuance of common stock under:
Changes in the redemption value of redeemable noncontrolling interest	1	12	1,310	12
Changes in noncontrolling interest from acquisition			65,472
Distributions to noncontrolling interest	(2,302)	(2,632)	(7,412)	(9,522)
Redemptions	(180)	(11)	(1,910)	(11)
Balance at period end	$ 129,626	$ 64,334	$ 129,626	$ 64,334