Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income	$ 162,477	$ 89,633
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	336,946	253,890
Amortization of discount on marketable securities	(9,012)	(6,555)
Amortization of (premium) discount and debt financing costs, net	(15,064)	(4,987)
Gain on sale of marketable securities and other investments	(598)	(886)
Company's share of gain on the sales of co-investments	(469)	(3,211)
Earnings from co-investments	(15,493)	(17,854)
Operating distributions from co-investments	28,632	20,122
Gains on the sales of real estate and land	(7,112)	(38,853)
Non cash merger and integration expenses	0	7,562
Equity-based compensation	5,511	4,996
Gain on remeasurement of co-investments	(34,014)	0
Changes in operating assets and liabilities:
Prepaid expense, receivables and other assets	(1,851)	8,923
Accounts payable and accrued liabilities	36,480	43,988
Other liabilities	1,475	1,393
Net cash provided by operating activities	487,908	358,161
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(327,799)	(438,088)
Redevelopment	(66,783)	(55,921)
Development acquisitions of and additions to real estate under development	(138,101)	(108,659)
Capital expenditures on rental properties	(42,809)	(21,074)
Acquisition of membership interest in co-investments	(115,724)	0
Proceeds from insurance for property losses	12,044	29,160
Proceeds from dispositions of real estate	74,485	61,331
BRE merger consideration paid	0	(555,826)
Proceeds from dispositions of co-investments	31,556	13,900
Contributions to co-investments	(119,120)	(128,268)
Changes in restricted cash and refundable deposits	38,282	(39,482)
Purchases of marketable securities	(14,300)	(15,516)
Sales and maturities of marketable securities and other investments	7,566	6,275
Collections of notes and other receivables	0	76,585
Non-operating distributions from co-investments	382	23,248
Net cash used in investing activities	(660,321)	(1,152,335)
Cash flows from financing activities:
Borrowings under debt agreements	1,068,032	1,737,322
Repayment of debt	(924,844)	(1,327,840)
Additions to deferred charges	(4,320)	(16,941)
Net proceeds from issuance of common stock	307,835	449,464
Net proceeds from stock options exercises	22,173	6,526
Distributions to noncontrolling interest	(15,789)	(13,217)
Redemption of noncontrolling interest	(2,621)	(4,707)
Common and preferred stock dividends paid	(272,000)	(177,400)
Net cash provided by financing activities	178,466	653,207
Cash acquired from the BRE merger	0	140,353
Cash acquired in consolidation of co-investment	4,005	0
Net increase (decrease) in cash and cash equivalents	10,058	(614)
Cash and cash equivalents at beginning of period	25,610	18,491
Cash and cash equivalents at end of period	35,668	17,877
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $12.2 million and $17.8 million capitalized in 2015 and 2014, respectively	135,736	93,342
Supplemental disclosure of noncash investing and financing activities:
Issuance of Operating Partnership units for contributed properties	0	1,419,816
Retirement of Operating Partnership units	0	(1,419,816)
Transfer from real estate under development to rental properties	308,069	71,496
Transfer from real estate under development to co-investments	5,913	81,332
Reclassifications of and changes in redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	1,333	18,764
Debt assumed in connection with acquisition of co-investment	114,435	0
Essex Portfolio, L.P. [Member]
Cash flows from operating activities:
Net income	162,477	89,633
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	336,946	253,890
Amortization of discount on marketable securities	(9,012)	(6,555)
Amortization of (premium) discount and debt financing costs, net	(15,064)	(4,987)
Gain on sale of marketable securities and other investments	(598)	(886)
Company's share of gain on the sales of co-investments	(469)	(3,211)
Earnings from co-investments	(15,493)	(17,854)
Operating distributions from co-investments	28,632	20,122
Gains on the sales of real estate and land	(7,112)	(38,853)
Non cash merger and integration expenses	0	7,562
Equity-based compensation	5,511	4,996
Gain on remeasurement of co-investments	(34,014)	0
Changes in operating assets and liabilities:
Prepaid expense, receivables and other assets	(1,851)	8,923
Accounts payable and accrued liabilities	36,480	43,988
Other liabilities	1,475	1,393
Net cash provided by operating activities	487,908	358,161
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(327,799)	(438,088)
Redevelopment	(66,783)	(55,921)
Development acquisitions of and additions to real estate under development	(138,101)	(108,659)
Capital expenditures on rental properties	(42,809)	(21,074)
Acquisition of membership interest in co-investments	(115,724)	0
Proceeds from insurance for property losses	12,044	29,160
Proceeds from dispositions of real estate	74,485	61,331
BRE merger consideration paid	0	(555,826)
Proceeds from dispositions of co-investments	31,556	13,900
Contributions to co-investments	(119,120)	(128,268)
Changes in restricted cash and refundable deposits	38,282	(39,482)
Purchases of marketable securities	(14,300)	(15,516)
Sales and maturities of marketable securities and other investments	7,566	6,275
Collections of notes and other receivables	0	76,585
Non-operating distributions from co-investments	382	23,248
Net cash used in investing activities	(660,321)	(1,152,335)
Cash flows from financing activities:
Borrowings under debt agreements	1,068,032	1,737,322
Repayment of debt	(924,844)	(1,327,840)
Additions to deferred charges	(4,320)	(16,941)
Net proceeds from issuance of common stock	307,835	449,464
Net proceeds from stock options exercises	22,173	6,526
Distributions to noncontrolling interest	(6,455)	(3,462)
Redemption of noncontrolling interest	(2,621)	(308)
Common and preferred stock dividends paid	(281,334)	(191,554)
Net cash provided by financing activities	178,466	653,207
Cash acquired from the BRE merger	0	140,353
Cash acquired in consolidation of co-investment	4,005	0
Net increase (decrease) in cash and cash equivalents	10,058	(614)
Cash and cash equivalents at beginning of period	25,610	18,491
Cash and cash equivalents at end of period	35,668	17,877
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $12.2 million and $17.8 million capitalized in 2015 and 2014, respectively	135,736	93,342
Supplemental disclosure of noncash investing and financing activities:
Issuance of Operating Partnership units for contributed properties	0	1,419,816
Retirement of Operating Partnership units	0	(1,419,816)
Transfer from real estate under development to rental properties	308,069	71,496
Transfer from real estate under development to co-investments	5,913	81,332
Reclassifications of and changes in redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	1,333	18,764
Debt assumed in connection with acquisition of co-investment	$ 114,435	$ 0