Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 115,295	$ 31,052
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	220,638	151,604
Amortization of discount on marketable securities	(5,777)	(3,965)
Amortization of (premium) discount and debt financing costs, net	(11,125)	(846)
Gain on sale of marketable securities	0	(886)
Company's share of gain on the sales of co-investment	(469)	(3,211)
Earnings from co-investments	(8,314)	(12,944)
Operating distributions from co-investments	14,804	12,091
Gains on the sales of real estate and land	(7,112)	(7,481)
Non cash merger and integration expenses	0	7,562
Equity-based compensation	3,457	3,625
Gain on remeasurement of co-investments	(34,014)	0
Changes in operating assets and liabilities:
Prepaid expense, receivables and other assets	(6,646)	2,425
Accounts payable and accrued liabilities	4,924	9,299
Other liabilities	1,387	665
Net cash provided by operating activities	287,048	188,990
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(314,890)	(108,820)
Redevelopment	(41,796)	(31,470)
Development acquisitions of and additions to real estate under development	(122,377)	(58,899)
Capital expenditures on rental properties	(24,673)	(13,710)
Acquisition of membership interest in co-investments	(115,724)	0
Proceeds from insurance for property losses	11,735	10,000
Proceeds from dispositions of real estate	74,485	14,123
BRE merger consideration paid	0	(555,826)
Proceeds from dispositions of co-investments	11,072	13,900
Contributions to co-investments	(97,512)	(58,029)
Changes in restricted cash and refundable deposits	49,808	(3,606)
Purchases of marketable securities	(7,250)	(14,341)
Sales and maturities of marketable securities	1,968	5,192
Collections of notes and other receivables	0	56,750
Non-operating distributions from co-investments	0	8,599
Net cash used in investing activities	(575,154)	(736,137)
Cash flows from financing activities:
Borrowings under debt agreements	923,431	1,321,044
Repayment of debt	(730,712)	(1,077,210)
Additions to deferred charges	(4,456)	(16,401)
Net proceeds from issuance of common stock	272,664	278,334
Net proceeds from stock options exercises	18,346	5,503
Distributions to noncontrolling interest	(11,033)	(7,510)
Redemption of noncontrolling interest	(2,488)	(2,550)
Common and preferred stock dividends paid	(177,019)	(94,961)
Net cash provided by financing activities	288,733	406,249
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	4,632	(545)
Cash and cash equivalents at beginning of period	25,610	18,491
Cash and cash equivalents at end of period	30,242	17,946
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $8.3 million and $11.7 million capitalized in 2015 and 2014, respectively	86,347	44,437
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	300,751	4,580
Transfer from real estate under development to co-investments	3,780	49,776
Reclassifications of and changes in redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	574	18,766
Debt assumed in connection with acquisition of co-investment	114,435	0
Essex Portfolio, L.P. [Member]
Cash flows from operating activities:
Net income	115,295	31,052
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	220,638	151,604
Amortization of discount on marketable securities	(5,777)	(3,965)
Amortization of (premium) discount and debt financing costs, net	(11,125)	(846)
Gain on sale of marketable securities	0	(886)
Company's share of gain on the sales of co-investment	(469)	(3,211)
Earnings from co-investments	(8,314)	(12,944)
Operating distributions from co-investments	14,804	12,091
Gains on the sales of real estate and land	(7,112)	(7,481)
Non cash merger and integration expenses	0	7,562
Equity-based compensation	3,457	3,625
Gain on remeasurement of co-investments	(34,014)	0
Changes in operating assets and liabilities:
Prepaid expense, receivables and other assets	(6,646)	2,425
Accounts payable and accrued liabilities	4,924	9,299
Other liabilities	1,387	665
Net cash provided by operating activities	287,048	188,990
Additions to real estate:
Acquisitions of real estate and acquisition related capital expenditures	(314,890)	(108,820)
Redevelopment	(41,796)	(31,470)
Development acquisitions of and additions to real estate under development	(122,377)	(58,899)
Capital expenditures on rental properties	(24,673)	(13,710)
Acquisition of membership interest in co-investments	(115,724)	0
Proceeds from insurance for property losses	11,735	10,000
Proceeds from dispositions of real estate	74,485	14,123
BRE merger consideration paid	0	(555,826)
Proceeds from dispositions of co-investments	11,072	13,900
Contributions to co-investments	(97,512)	(58,029)
Changes in restricted cash and refundable deposits	49,808	(3,606)
Purchases of marketable securities	(7,250)	(14,341)
Sales and maturities of marketable securities	1,968	5,192
Collections of notes and other receivables	0	56,750
Non-operating distributions from co-investments	0	8,599
Net cash used in investing activities	(575,154)	(736,137)
Cash flows from financing activities:
Borrowings under debt agreements	923,431	1,321,044
Repayment of debt	(730,712)	(1,077,210)
Additions to deferred charges	(4,456)	(16,401)
Net proceeds from issuance of common stock	272,664	278,334
Net proceeds from stock options exercises	18,346	5,503
Distributions to noncontrolling interest	(4,884)	(2,045)
Redemption of noncontrolling interest	(2,488)	(414)
Common and preferred stock dividends paid	(183,168)	(102,562)
Net cash provided by financing activities	288,733	406,249
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	4,632	(545)
Cash and cash equivalents at beginning of period	25,610	18,491
Cash and cash equivalents at end of period	30,242	17,946
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $8.3 million and $11.7 million capitalized in 2015 and 2014, respectively	86,347	44,437
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	300,751	4,580
Transfer from real estate under development to co-investments	3,780	47,776
Reclassifications of and changes in redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	574	18,766
Debt assumed in connection with acquisition of co-investment	$ 114,435	$ 0