Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 125,505	$ 96,639
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	120,568	119,105
Amortization of discount on marketable securities	(5,311)	(4,157)
Amortization of discount (premium) and debt financing costs, net	529	(664)
Loss (gain) on sale of marketable securities	58	(680)
Unrealized (gain) loss on equity securities recognized through income	(4,510)	876
Earnings from co-investments	(16,276)	(32,774)
Operating distributions from co-investments	17,804	40,437
Accrued interest from notes and other receivables	(1,424)	(1,294)
Equity-based compensation	2,068	2,090
Gain on early retirement of debt, net	(1,336)	0
Gain on remeasurement of co-investment	(31,535)	0
Changes in operating assets and liabilities:
Prepaid expenses, receivables, operating lease right-of-use assets, and other assets	(4,730)	(3,716)
Accounts payable, accrued liabilities, and operating lease liabilities	53,895	52,151
Other liabilities	454	345
Net cash provided by operating activities	255,759	268,358
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(44,984)	(2,873)
Redevelopment	(14,157)	(15,893)
Development acquisitions of and additions to real estate under development	(39,306)	(38,203)
Capital expenditures on rental properties	(17,075)	(14,947)
Collections of notes and other receivables	2,500	29,500
Proceeds from insurance for property losses	1,583	565
Contributions to co-investments	(126,248)	(56,020)
Changes in refundable deposits	5	410
Purchases of marketable securities	(8,413)	(13,437)
Sales and maturities of marketable securities	16,847	9,579
Non-operating distributions from co-investments	10,000	2,330
Net cash used in investing activities	(219,248)	(98,989)
Cash flows from financing activities:
Proceeds from unsecured debt and mortgage notes	498,234	298,773
Payments on unsecured debt and mortgage notes	(360,975)	(83,748)
Proceeds from lines of credit	567,029	256,832
Repayments of lines of credit	(567,029)	(435,832)
Retirement of common stock	(56,989)	(3,774)
Additions to deferred charges	(5,445)	(3,283)
Net proceeds from issuance of common stock	(20)	(67)
Net proceeds from stock options exercised	6,699	1,222
Payments related to tax withholding for share-based compensation	(3,495)	(11)
Distributions to noncontrolling interest	(6,978)	(5,926)
Redemption of noncontrolling interest	(12,213)	0
Redemption of redeemable noncontrolling interest	(73)	0
Common and preferred stock dividends paid	(122,525)	(115,603)
Net cash used in financing activities	(63,780)	(91,417)
Net increase (decrease) in unrestricted and restricted cash and cash equivalents	(27,269)	77,952
Unrestricted and restricted cash and cash equivalents at beginning of period	151,395	61,126
Unrestricted and restricted cash and cash equivalents at end of period	124,126	139,078
Supplemental disclosure of cash flow information:
Cash paid for interest (net of $5.9 million and $4.2 million capitalized in 2019 and 2018, respectively)	41,914	40,306
Operating cash flows from operating leases	1,694	0
Supplemental disclosure of noncash investing and financing activities:
Transfers between real estate under development to rental properties, net	0	1
Transfer from real estate under development to co-investments	313	365
Reclassifications to redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	1,767	1,953
Initial recognition of operating lease right-of-use assets	77,645	0
Initial recognition of operating lease liabilities	79,693	0
Essex Portfolio, L.P. [Member]
Cash flows from operating activities:
Net income	125,505	96,639
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	120,568	119,105
Amortization of discount on marketable securities	(5,311)	(4,157)
Amortization of discount (premium) and debt financing costs, net	529	(664)
Loss (gain) on sale of marketable securities	58	(680)
Unrealized (gain) loss on equity securities recognized through income	(4,510)	876
Earnings from co-investments	(16,276)	(32,774)
Operating distributions from co-investments	17,804	40,437
Accrued interest from notes and other receivables	(1,424)	(1,294)
Equity-based compensation	2,068	2,090
Gain on early retirement of debt, net	(1,336)	0
Gain on remeasurement of co-investment	(31,535)	0
Changes in operating assets and liabilities:
Prepaid expenses, receivables, operating lease right-of-use assets, and other assets	(4,730)	(3,716)
Accounts payable, accrued liabilities, and operating lease liabilities	53,895	52,151
Other liabilities	454	345
Net cash provided by operating activities	255,759	268,358
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(44,984)	(2,873)
Redevelopment	(14,157)	(15,893)
Development acquisitions of and additions to real estate under development	(39,306)	(38,203)
Capital expenditures on rental properties	(17,075)	(14,947)
Collections of notes and other receivables	2,500	29,500
Proceeds from insurance for property losses	1,583	565
Contributions to co-investments	(126,248)	(56,020)
Changes in refundable deposits	5	410
Purchases of marketable securities	(8,413)	(13,437)
Sales and maturities of marketable securities	16,847	9,579
Non-operating distributions from co-investments	10,000	2,330
Net cash used in investing activities	(219,248)	(98,989)
Cash flows from financing activities:
Proceeds from unsecured debt and mortgage notes	498,234	298,773
Payments on unsecured debt and mortgage notes	(360,975)	(83,748)
Proceeds from lines of credit	567,029	256,832
Repayments of lines of credit	(567,029)	(435,832)
Retirement of common stock	(56,989)	(3,774)
Additions to deferred charges	(5,445)	(3,283)
Net proceeds from issuance of common stock	(20)	(67)
Net proceeds from stock options exercised	6,699	1,222
Payments related to tax withholding for share-based compensation	(3,495)	(11)
Distributions to noncontrolling interest	(1,959)	(2,267)
Redemption of noncontrolling interest	(12,213)	0
Redemption of redeemable noncontrolling interest	(73)	0
Common and preferred stock dividends paid	(127,544)	(119,262)
Net cash used in financing activities	(63,780)	(91,417)
Net increase (decrease) in unrestricted and restricted cash and cash equivalents	(27,269)	77,952
Unrestricted and restricted cash and cash equivalents at beginning of period	151,395	61,126
Unrestricted and restricted cash and cash equivalents at end of period	124,126	139,078
Supplemental disclosure of cash flow information:
Cash paid for interest (net of $5.9 million and $4.2 million capitalized in 2019 and 2018, respectively)	41,914	40,306
Operating cash flows from operating leases	1,694	0
Supplemental disclosure of noncash investing and financing activities:
Transfers between real estate under development to rental properties, net	0	1
Transfer from real estate under development to co-investments	313	365
Reclassifications to redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	1,767	1,953
Initial recognition of operating lease right-of-use assets	77,645	0
Initial recognition of operating lease liabilities	$ 79,693	$ 0