Condensed Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Total revenues	$ 350,917	$ 344,369	$ 1,046,895	$ 1,018,835
Expenses:
Property operating, excluding real estate taxes	59,100	59,033	174,506	171,028
Real estate taxes	38,675	37,531	112,378	108,283
Corporate-level property management expenses	7,761	7,573	23,313	22,604
Depreciation and amortization	120,852	117,451	359,287	350,893
General and administrative	10,601	9,788	36,539	30,726
Expensed acquisition and investment related costs	31	324	156	1,154
Total expenses	237,020	231,700	706,179	684,688
Earnings from operations	113,897	112,669	340,716	334,147
Interest expense	(55,196)	(55,938)	(166,335)	(167,333)
Total return swap income	2,184	2,538	6,682	7,653
Interest and other income	8,437	5,790	21,241	17,916
Equity income from co-investments	16,788	19,727	64,611	40,934
Gain on sale of real estate and land	0	249	22,244	26,423
Gain on remeasurement of co-investment	0	0	0	88,641
Net income	86,110	85,035	289,159	348,381
Net income attributable to noncontrolling interest	(5,135)	(5,312)	(16,826)	(18,935)
Net income available to common stockholders	80,975	79,723	272,333	329,446
Comprehensive income	89,100	88,870	301,708	356,102
Comprehensive income attributable to noncontrolling interest	(5,235)	(5,438)	(17,243)	(19,190)
Comprehensive income attributable to controlling interest	$ 83,865	$ 83,432	$ 284,465	$ 336,912
Basic:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.23	$ 1.21	$ 4.12	$ 5.01
Weighted average number of shares/common units outstanding during the period (in shares)	66,052,108	65,994,896	66,047,990	65,759,450
Diluted:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.22	$ 1.21	$ 4.12	$ 5.00
Weighted average number of shares/common units outstanding during the period (in shares)	66,103,812	66,078,283	66,093,004	65,836,965
Dividends/Distributions per common share/unit (in dollars per share)	$ 1.86	$ 1.75	$ 5.58	$ 5.25
Rental and Other Property Revenues [Member]
Revenues:
Total revenues	$ 348,610	$ 341,974	$ 1,040,083	$ 1,011,908
Management and Other Fees From Affiliates Income [Member]
Revenues:
Total revenues	2,307	2,395	6,812	6,927
Essex Portfolio, L.P. [Member]
Revenues:
Total revenues	350,917	344,369	1,046,895	1,018,835
Expenses:
Property operating, excluding real estate taxes	59,100	59,033	174,506	171,028
Real estate taxes	38,675	37,531	112,378	108,283
Corporate-level property management expenses	7,761	7,573	23,313	22,604
Depreciation and amortization	120,852	117,451	359,287	350,893
General and administrative	10,601	9,788	36,539	30,726
Expensed acquisition and investment related costs	31	324	156	1,154
Total expenses	237,020	231,700	706,179	684,688
Earnings from operations	113,897	112,669	340,716	334,147
Interest expense	(55,196)	(55,938)	(166,335)	(167,333)
Total return swap income	2,184	2,538	6,682	7,653
Interest and other income	8,437	5,790	21,241	17,916
Equity income from co-investments	16,788	19,727	64,611	40,934
Gain on sale of real estate and land	0	249	22,244	26,423
Gain on remeasurement of co-investment	0	0	0	88,641
Net income	86,110	85,035	289,159	348,381
Net income attributable to noncontrolling interest	(2,346)	(2,591)	(7,445)	(7,646)
Net income available to common stockholders	83,764	82,444	281,714	340,735
Comprehensive income	89,100	88,870	301,708	356,102
Comprehensive income attributable to noncontrolling interest	(2,346)	(2,591)	(7,445)	(7,646)
Comprehensive income attributable to controlling interest	$ 86,754	$ 86,279	$ 294,263	$ 348,456
Basic:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.23	$ 1.21	$ 4.12	$ 5.01
Weighted average number of shares/common units outstanding during the period (in shares)	68,325,091	68,246,008	68,321,153	68,011,123
Diluted:
Net income available to common stockholders/unitholders (in dollars per share)	$ 1.23	$ 1.21	$ 4.12	$ 5.00
Weighted average number of shares/common units outstanding during the period (in shares)	68,376,795	68,329,395	68,366,167	68,088,638
Dividends/Distributions per common share/unit (in dollars per share)	$ 1.86	$ 1.75	$ 5.58	$ 5.25
Essex Portfolio, L.P. [Member] | Rental and Other Property Revenues [Member]
Revenues:
Total revenues	$ 348,610	$ 341,974	$ 1,040,083	$ 1,011,908
Essex Portfolio, L.P. [Member] | Management and Other Fees From Affiliates Income [Member]
Revenues:
Total revenues	$ 2,307	$ 2,395	$ 6,812	$ 6,927