Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income	$ 86,907	$ 64,753
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	109,707	106,907
Amortization of discount on marketable securities and other investments	(3,756)	(2,856)
Amortization of (premium) discount and debt financing costs, net	(3,795)	(6,530)
Gain on sale of marketable securities	(740)	0
Company's share of gain on the sales of co-investments	(7,435)	0
Income from early redemption of preferred equity investments	0	(469)
Earnings from co-investments	(7,633)	(3,842)
Operating distributions from co-investments	9,753	6,055
Gain on the sale of real estate and land	(20,258)	(7,112)
Equity-based compensation	1,490	1,370
Gain on remeasurement of co-investments	0	(21,362)
Changes in operating assets and liabilities:
Prepaid expenses, receivables and other assets	846	3,548
Accounts payable and accrued liabilities	35,200	21,741
Other liabilities	324	346
Net cash provided by operating activities	200,610	162,549
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(110,309)	(199,190)
Redevelopment	(24,151)	(19,140)
Development acquisitions of and additions to real estate under development	(22,656)	(90,925)
Capital expenditures on rental properties	(5,688)	(16,196)
Acquisition of membership interest in co-investments	0	(41,513)
Proceeds from insurance for property losses	435	4,589
Proceeds from dispositions of real estate	48,008	74,485
Contributions to co-investments	(50,591)	(48,650)
Changes in restricted cash and refundable deposits	59,346	45,145
Purchases of marketable securities	(1,344)	(7,250)
Sales and maturities of marketable securities	5,045	717
Non-operating distributions from co-investments	21,146	11,072
Net cash used in investing activities	(80,759)	(286,856)
Cash flows from financing activities:
Borrowings under debt agreements	305,895	756,562
Repayment of debt	(309,903)	(536,830)
Additions to deferred charges	(1,037)	(4,456)
Net proceeds from issuance of common stock	(134)	174,592
Net proceeds from stock options exercised	5,232	15,613
Distributions to noncontrolling interest	(4,858)	(3,574)
Redemption of noncontrolling interest	(1,089)	(2,154)
Common and preferred stock dividends paid	(95,476)	(83,663)
Net cash (used in) provided by financing activities	(101,370)	316,090
Cash acquired in consolidation of co-investment	0	1,807
Net increase in cash and cash equivalents	18,481	193,590
Cash and cash equivalents at beginning of period	29,683	25,610
Cash and cash equivalents at end of period	48,164	219,200
Supplemental disclosure of cash flow information:
Cash paid for interest, net of interest capitalized in 2016 and 2015	48,109	50,343
Cash paid for interest, capitalized	3,100	4,300
Supplemental disclosure of noncash investing and financing activities:
Transfers between real estate under development to rental properties, net	107,643	162,345
Transfer from real estate under development to co-investments	2,338	1,562
Reclassifications to redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	751	1,660
Debt assumed in connection with acquisition	48,832	114,435
Essex Portfolio, L.P. [Member]
Cash flows from operating activities:
Net income	86,907	64,753
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	109,707	106,907
Amortization of discount on marketable securities and other investments	(3,756)	(2,856)
Amortization of (premium) discount and debt financing costs, net	(3,795)	(6,530)
Gain on sale of marketable securities	(740)	0
Company's share of gain on the sales of co-investments	(7,435)	0
Income from early redemption of preferred equity investments	0	(469)
Earnings from co-investments	(7,633)	(3,842)
Operating distributions from co-investments	9,753	6,055
Gain on the sale of real estate and land	(20,258)	(7,112)
Equity-based compensation	1,490	1,370
Gain on remeasurement of co-investments	0	(21,362)
Changes in operating assets and liabilities:
Prepaid expenses, receivables and other assets	846	3,548
Accounts payable and accrued liabilities	35,200	21,741
Other liabilities	324	346
Net cash provided by operating activities	200,610	162,549
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(110,309)	(199,190)
Redevelopment	(24,151)	(19,140)
Development acquisitions of and additions to real estate under development	(22,656)	(90,925)
Capital expenditures on rental properties	(5,688)	(16,196)
Acquisition of membership interest in co-investments	0	(41,513)
Proceeds from insurance for property losses	435	4,589
Proceeds from dispositions of real estate	48,008	74,485
Contributions to co-investments	(50,591)	(48,650)
Changes in restricted cash and refundable deposits	59,346	45,145
Purchases of marketable securities	(1,344)	(7,250)
Sales and maturities of marketable securities	5,045	717
Non-operating distributions from co-investments	21,146	11,072
Net cash used in investing activities	(80,759)	(286,856)
Cash flows from financing activities:
Borrowings under debt agreements	305,895	756,562
Repayment of debt	(309,903)	(536,830)
Additions to deferred charges	(1,037)	(4,456)
Net proceeds from issuance of common stock	(134)	174,592
Net proceeds from stock options exercised	5,232	15,613
Distributions to noncontrolling interest	(1,528)	(221)
Redemption of noncontrolling interest	(1,089)	(2,154)
Common and preferred stock dividends paid	(98,806)	(87,016)
Net cash (used in) provided by financing activities	(101,370)	316,090
Cash acquired in consolidation of co-investment	0	1,807
Net increase in cash and cash equivalents	18,481	193,590
Cash and cash equivalents at beginning of period	29,683	25,610
Cash and cash equivalents at end of period	48,164	219,200
Supplemental disclosure of cash flow information:
Cash paid for interest, net of interest capitalized in 2016 and 2015	48,109	50,343
Cash paid for interest, capitalized	3,100	4,300
Supplemental disclosure of noncash investing and financing activities:
Transfers between real estate under development to rental properties, net	107,643	162,345
Transfer from real estate under development to co-investments	2,338	1,562
Reclassifications to redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	751	1,660
Debt assumed in connection with acquisition	$ 48,832	$ 114,435