Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 464,448	$ 413,599	$ 458,043
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	483,750	479,884	468,881
Amortization of discount on marketable securities	(28,491)	(17,637)	(15,119)
Amortization of (premium) discount and debt financing costs, net	5,689	(2,587)	(5,948)
Gain on sale of marketable securities	(1,271)	(737)	(1,909)
Unrealized (gain) loss on equity securities recognized through income	(5,710)	5,159	0
Company's share of gain on the sales of co-investments	(51,097)	(10,569)	(44,837)
Earnings from co-investments	(61,039)	(78,563)	(41,608)
Operating distributions from co-investments	99,277	99,593	76,764
Accrued interest from notes and other receivables	(6,012)	(5,436)	(4,030)
Impairment loss	7,105	0	0
(Gain) loss on the sale of real estate and land	3,164	(61,861)	(26,423)
Equity-based compensation	7,010	7,135	9,286
(Gain) loss on early retirement of debt, net	(3,717)	0	1,796
Gain on remeasurement of co-investment	(31,535)	(1,253)	(88,641)
Changes in operating assets and liabilities:
Prepaid expenses, receivables, operating lease right-of-use assets, and other assets	5,751	(1,203)	(3,004)
Accounts payable, accrued liabilities, and operating lease liabilities	29,551	(145)	(13,474)
Other liabilities	2,206	1,175	(170)
Net cash provided by operating activities	919,079	826,554	769,607
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(133,825)	(15,311)	(206,194)
Redevelopment	(70,295)	(73,000)	(69,928)
Development acquisitions of and additions to real estate under development	(158,234)	(182,772)	(137,733)
Capital expenditures on rental properties	(101,689)	(81,684)	(72,812)
Investments in notes receivable	(231,400)	0	(106,461)
Collections of notes and other receivables	168,720	29,500	55,000
Proceeds from insurance for property losses	3,734	1,408	648
Proceeds from dispositions of real estate	23,214	347,587	132,039
Contributions to co-investments	(402,284)	(162,437)	(293,363)
Changes in refundable deposits	5	(414)	837
Purchases of marketable securities	(46,458)	(37,952)	(67,893)
Sales and maturities of marketable securities	(147,531)	(31,521)	(35,481)
Non-operating distributions from co-investments	273,290	83,661	162,439
Net cash used in investing activities	(527,691)	(59,893)	(567,940)
Cash flows from financing activities:
Proceeds from unsecured debt and mortgage notes	1,045,290	298,773	597,981
Payments on unsecured debt and mortgage notes	(1,026,616)	(230,398)	(561,160)
Proceeds from lines of credit	1,939,213	742,961	982,246
Repayments of lines of credit	(1,884,213)	(921,961)	(928,246)
Retirement of common stock	(56,989)	(51,233)	0
Additions to deferred charges	(10,898)	(4,250)	(4,108)
Payments related to debt prepayment penalties	(1,406)	0	(1,630)
Net proceeds from issuance of common stock	72,539	(919)	89,055
Net proceeds from stock options exercised	37,467	6,213	26,635
Payments related to tax withholding for share-based compensation	(3,688)	(869)	(316)
Distributions to noncontrolling interest	(27,993)	(29,050)	(26,552)
Redemption of noncontrolling interest	(36,568)	(1,333)	(28,580)
Redemption of redeemable noncontrolling interest	(73)	(144)	(5,543)
Common and preferred stock dividends paid	(507,754)	(484,182)	(450,625)
Net cash used in financing activities	(461,689)	(676,392)	(310,843)
Net increase (decrease) in unrestricted and restricted cash and cash equivalents	(70,301)	90,269	(109,176)
Unrestricted and restricted cash and cash equivalents at beginning of period	151,395	61,126	170,302
Unrestricted and restricted cash and cash equivalents at end of period	81,094	151,395	61,126
Supplemental disclosure of cash flow information:
Cash paid for interest, net of capitalized interest	194,418	203,803	212,163
Interest capitalized	24,169	18,708	13,860
Operating cash flows from operating leases	6,811	0	0
Supplemental disclosure of noncash investing and financing activities:
Issuance of Operating Partnership units for contributed properties	0	7,919	0
Issuance of DownREIT units in connection with acquisition of real estate	65,472	0	22,506
Transfers between real estate under development to rental properties, net	19,812	100,415	2,413
Transfer from real estate under development to co-investments	671	853	5,075
Reclassifications to redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	2,008	1,165	65
Redemption of redeemable noncontrolling interest via reduction of note receivable	0	4,751	0
Debt assumed in connection with acquisition	143,006	45,804	51,882
Repayment of mortgage note from new financing proceeds	0	52,000	0
Essex Portfolio, L.P.
Cash flows from operating activities:
Net income	464,448	413,599	458,043
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	483,750	479,884	468,881
Amortization of discount on marketable securities	(28,491)	(17,637)	(15,119)
Amortization of (premium) discount and debt financing costs, net	5,689	(2,587)	(5,948)
Gain on sale of marketable securities	(1,271)	(737)	(1,909)
Unrealized (gain) loss on equity securities recognized through income	(5,710)	5,159	0
Company's share of gain on the sales of co-investments	(51,097)	(10,569)	(44,837)
Earnings from co-investments	(61,039)	(78,563)	(41,608)
Operating distributions from co-investments	99,277	99,593	76,764
Accrued interest from notes and other receivables	(6,012)	(5,436)	(4,030)
Impairment loss	7,105	0	0
(Gain) loss on the sale of real estate and land	3,164	(61,861)	(26,423)
Equity-based compensation	7,010	7,135	9,286
(Gain) loss on early retirement of debt, net	(3,717)	0	1,796
Gain on remeasurement of co-investment	(31,535)	(1,253)	(88,641)
Changes in operating assets and liabilities:
Prepaid expenses, receivables, operating lease right-of-use assets, and other assets	5,751	(1,203)	(3,004)
Accounts payable, accrued liabilities, and operating lease liabilities	29,551	(145)	(13,474)
Other liabilities	2,206	1,175	(170)
Net cash provided by operating activities	919,079	826,554	769,607
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(133,825)	(15,311)	(206,194)
Redevelopment	(70,295)	(73,000)	(69,928)
Development acquisitions of and additions to real estate under development	(158,234)	(182,772)	(137,733)
Capital expenditures on rental properties	(101,689)	(81,684)	(72,812)
Investments in notes receivable	(231,400)	0	(106,461)
Collections of notes and other receivables	168,720	29,500	55,000
Proceeds from insurance for property losses	3,734	1,408	648
Proceeds from dispositions of real estate	23,214	347,587	132,039
Contributions to co-investments	(402,284)	(162,437)	(293,363)
Changes in refundable deposits	5	(414)	837
Purchases of marketable securities	(46,458)	(37,952)	(67,893)
Sales and maturities of marketable securities	(147,531)	(31,521)	(35,481)
Non-operating distributions from co-investments	273,290	83,661	162,439
Net cash used in investing activities	(527,691)	(59,893)	(567,940)
Cash flows from financing activities:
Proceeds from unsecured debt and mortgage notes	1,045,290	298,773	597,981
Payments on unsecured debt and mortgage notes	(1,026,616)	(230,398)	(561,160)
Proceeds from lines of credit	1,939,213	742,961	982,246
Repayments of lines of credit	(1,884,213)	(921,961)	(928,246)
Retirement of common stock	(56,989)	(51,233)	0
Additions to deferred charges	(10,898)	(4,250)	(4,108)
Payments related to debt prepayment penalties	(1,406)	0	(1,630)
Net proceeds from issuance of common stock	72,539	(919)	89,055
Net proceeds from stock options exercised	37,467	6,213	26,635
Payments related to tax withholding for share-based compensation	(3,688)	(869)	(316)
Distributions to noncontrolling interest	(7,288)	(8,518)	(7,752)
Redemption of noncontrolling interest	(36,568)	(1,333)	(28,580)
Redemption of redeemable noncontrolling interest	(73)	(144)	(5,543)
Common and preferred stock dividends paid	(528,459)	(504,714)	(469,425)
Net cash used in financing activities	(461,689)	(676,392)	(310,843)
Net increase (decrease) in unrestricted and restricted cash and cash equivalents	(70,301)	90,269	(109,176)
Unrestricted and restricted cash and cash equivalents at beginning of period	151,395	61,126	170,302
Unrestricted and restricted cash and cash equivalents at end of period	81,094	151,395	61,126
Supplemental disclosure of cash flow information:
Cash paid for interest, net of capitalized interest	194,418	203,803	212,163
Interest capitalized	24,169	18,708	13,860
Operating cash flows from operating leases	6,811	0	0
Supplemental disclosure of noncash investing and financing activities:
Issuance of Operating Partnership units for contributed properties	0	7,919	0
Issuance of DownREIT units in connection with acquisition of real estate	65,472	0	22,506
Transfers between real estate under development to rental properties, net	19,812	100,415	2,413
Transfer from real estate under development to co-investments	671	853	5,075
Reclassifications to redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	2,008	1,165	65
Redemption of redeemable noncontrolling interest via reduction of note receivable	0	4,751	0
Initial recognition of operating lease right-of-use assets	77,645	0	0
Initial recognition of operating lease liabilities	79,693	0	0
Debt assumed in connection with acquisition	143,006	45,804	51,882
Repayment of mortgage note from new financing proceeds	$ 0	$ 52,000	$ 0