Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Revenues	$ 1,400,053	$ 1,363,899	$ 1,294,001
Expenses:
Property operating, excluding real estate taxes	233,809	229,076	219,655
Real estate taxes	151,525	146,310	139,162
Corporate-level property management expenses	31,062	30,156	30,110
Depreciation and amortization	479,884	468,881	441,682
General and administrative	53,451	41,385	40,751
Expensed acquisition and investment related costs	194	1,569	1,841
Total expenses	949,925	917,377	873,201
Earnings from operations	450,128	446,522	420,800
Interest expense	(220,492)	(222,894)	(219,654)
Total return swap income	8,707	10,098	11,716
Interest and other income	23,010	24,604	27,305
Equity income from co-investments	89,132	86,445	48,698
Loss on early retirement of debt	0	(1,796)	(606)
Gain on sale of real estate and land	61,861	26,423	154,561
Deferred tax expense on gain on sale of real estate and land	0	0	(4,410)
Gain on remeasurement of co-investment	1,253	88,641	0
Net income	413,599	458,043	438,410
Net income attributable to noncontrolling interest	(23,446)	(24,984)	(23,431)
Net income attributable to controlling interest	390,153	433,059	414,979
Dividends to preferred stockholders	0	0	(1,314)
Excess of redemption value of preferred stock over the carrying value	0	0	(2,541)
Net income available to common stockholders	$ 390,153	$ 433,059	$ 411,124
Basic:
Net income available to common stockholders/unitholders (in dollars per share)	$ 5.91	$ 6.58	$ 6.28
Weighted average number of shares/units outstanding during the year (in shares)	66,041,058	65,829,155	65,471,540
Diluted:
Net income available to common stockholders/unitholders (in dollars per share)	$ 5.90	$ 6.57	$ 6.27
Weighted average number of shares/units outstanding during the year (in shares)	66,085,089	65,898,255	65,587,816
Essex Portfolio, L.P. [Member]
Revenues:
Revenues	$ 1,400,053	$ 1,363,899	$ 1,294,001
Expenses:
Property operating, excluding real estate taxes	233,809	229,076	219,655
Real estate taxes	151,525	146,310	139,162
Corporate-level property management expenses	31,062	30,156	30,110
Depreciation and amortization	479,884	468,881	441,682
General and administrative	53,451	41,385	40,751
Expensed acquisition and investment related costs	194	1,569	1,841
Total expenses	949,925	917,377	873,201
Earnings from operations	450,128	446,522	420,800
Interest expense	(220,492)	(222,894)	(219,654)
Total return swap income	8,707	10,098	11,716
Interest and other income	23,010	24,604	27,305
Equity income from co-investments	89,132	86,445	48,698
Loss on early retirement of debt	0	(1,796)	(606)
Gain on sale of real estate and land	61,861	26,423	154,561
Deferred tax expense on gain on sale of real estate and land	0	0	(4,410)
Gain on remeasurement of co-investment	1,253	88,641	0
Net income	413,599	458,043	438,410
Net income attributable to noncontrolling interest	(9,994)	(10,159)	(9,342)
Net income attributable to controlling interest	403,605	447,884	429,068
Dividends to preferred stockholders	0	0	(1,314)
Excess of redemption value of preferred stock over the carrying value	0	0	(2,541)
Net income available to common stockholders	$ 403,605	$ 447,884	$ 425,213
Basic:
Net income available to common stockholders/unitholders (in dollars per share)	$ 5.91	$ 6.58	$ 6.28
Weighted average number of shares/units outstanding during the year (in shares)	68,315,999	68,081,730	67,695,640
Diluted:
Net income available to common stockholders/unitholders (in dollars per share)	$ 5.90	$ 6.57	$ 6.27
Weighted average number of shares/units outstanding during the year (in shares)	68,360,030	68,150,830	67,811,916
Rental and other property [Member]
Revenues:
Revenues	$ 1,390,870	$ 1,354,325	$ 1,285,723
Rental and other property [Member] | Essex Portfolio, L.P. [Member]
Revenues:
Revenues	1,390,870	1,354,325	1,285,723
Management and other fees from affiliates [Member]
Revenues:
Revenues	9,183	9,574	8,278
Management and other fees from affiliates [Member] | Essex Portfolio, L.P. [Member]
Revenues:
Revenues	$ 9,183	$ 9,574	$ 8,278