Condensed Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues:
Total revenues	$ 348,723	$ 339,062	$ 695,978	$ 674,466
Expenses:
Property operating, excluding real estate taxes	58,156	55,859	115,406	111,995
Real estate taxes	35,990	34,884	73,703	70,752
Corporate-level property management expenses	7,782	7,522	15,552	15,031
Depreciation and amortization	119,330	117,939	238,435	233,442
General and administrative	11,125	10,337	25,938	20,938
Expensed acquisition and investment related costs	68	274	125	830
Total expenses	232,451	226,815	469,159	452,988
Earnings from operations	116,272	112,247	226,819	221,478
Interest expense	(56,278)	(56,812)	(111,139)	(111,395)
Total return swap income	2,228	2,531	4,498	5,115
Interest and other income	6,895	5,362	12,804	12,126
Equity income from co-investments	15,049	10,308	47,823	21,207
Gain on sale of real estate and land	22,244	0	22,244	26,174
Gain on remeasurement of co-investment	0	2,159	0	88,641
Net income	106,410	75,795	203,049	263,346
Net income attributable to noncontrolling interest	(5,970)	(5,036)	(11,691)	(13,623)
Net income available to common stockholders	100,440	70,759	191,358	249,723
Comprehensive income	109,793	77,468	212,608	267,232
Comprehensive income attributable to noncontrolling interest	(6,082)	(5,091)	(12,008)	(13,752)
Comprehensive income attributable to controlling interest	$ 103,711	$ 72,377	$ 200,600	$ 253,480
Basic:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.52	$ 1.08	$ 2.90	$ 3.80
Weighted average number of shares/common units outstanding during the period (in shares)	66,047,751	65,729,074	66,045,897	65,639,775
Diluted:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.52	$ 1.08	$ 2.90	$ 3.80
Weighted average number of shares/common units outstanding during the period (in shares)	66,096,349	65,819,694	66,088,803	65,942,018
Dividends/Distributions per common share/unit (in dollars per share)	$ 1.86	$ 1.75	$ 3.72	$ 3.5
Rental and Other Property Revenues [Member]
Revenues:
Total revenues	$ 346,526	$ 336,766	$ 691,473	$ 669,934
Management and Other Fees From Affiliates Income [Member]
Revenues:
Total revenues	2,197	2,296	4,505	4,532
Essex Portfolio, L.P. [Member]
Revenues:
Total revenues	348,723	339,062	695,978	674,466
Expenses:
Property operating, excluding real estate taxes	58,156	55,859	115,406	111,995
Real estate taxes	35,990	34,884	73,703	70,752
Corporate-level property management expenses	7,782	7,522	15,552	15,031
Depreciation and amortization	119,330	117,939	238,435	233,442
General and administrative	11,125	10,337	25,938	20,938
Expensed acquisition and investment related costs	68	274	125	830
Total expenses	232,451	226,815	469,159	452,988
Earnings from operations	116,272	112,247	226,819	221,478
Interest expense	(56,278)	(56,812)	(111,139)	(111,395)
Total return swap income	2,228	2,531	4,498	5,115
Interest and other income	6,895	5,362	12,804	12,126
Equity income from co-investments	15,049	10,308	47,823	21,207
Gain on sale of real estate and land	22,244	0	22,244	26,174
Gain on remeasurement of co-investment	0	2,159	0	88,641
Net income	106,410	75,795	203,049	263,346
Net income attributable to noncontrolling interest	(2,510)	(2,614)	(5,099)	(5,055)
Net income available to common stockholders	103,900	73,181	197,950	258,291
Comprehensive income	109,793	77,468	212,608	267,232
Comprehensive income attributable to noncontrolling interest	(2,510)	(2,614)	(5,099)	(5,055)
Comprehensive income attributable to controlling interest	$ 107,283	$ 74,854	$ 207,509	$ 262,177
Basic:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.52	$ 1.08	$ 2.90	$ 3.80
Weighted average number of shares/common units outstanding during the period (in shares)	68,320,849	67,980,761	68,319,151	67,891,734
Diluted:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.52	$ 1.08	$ 2.90	$ 3.80
Weighted average number of shares/common units outstanding during the period (in shares)	68,369,447	68,071,381	68,362,057	68,193,977
Dividends/Distributions per common share/unit (in dollars per share)	$ 1.86	$ 1.75	$ 3.72	$ 3.5
Essex Portfolio, L.P. [Member] | Rental and Other Property Revenues [Member]
Revenues:
Total revenues	$ 346,526	$ 336,766	$ 691,473	$ 669,934
Essex Portfolio, L.P. [Member] | Management and Other Fees From Affiliates Income [Member]
Revenues:
Total revenues	$ 2,197	$ 2,296	$ 4,505	$ 4,532