Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net income	$ 64,753	$ 26,406
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	106,907	50,312
Amortization of discount on marketable securities	(2,856)	(1,938)
Amortization of (premium) discount and debt financing costs, net	(6,530)	2,986
Gain on sale of marketable securities	0	(427)
Company's share of gain on the sales of co-investment	(469)	(3,211)
Earnings from co-investments	(3,842)	(7,315)
Company's/Operating Partnership's share of gain on the sales of co-investment	6,055	9,569
Gains on the sales of real estate and land	(7,112)	(7,481)
Non cash merger and integration expenses	0	3,750
Equity-based compensation	1,370	1,233
Gain on remeasurement of co-investment	(21,362)	0
Changes in operating assets and liabilities:
Prepaid expense, receivables and other assets	3,548	2,787
Accounts payable and accrued liabilities	21,741	15,131
Other liabilities	346	92
Net cash provided by operating activities	162,549	91,894
Additions to real estate:
Acquisitions of real estate	(199,190)	(33,825)
Redevelopment	(19,140)	(10,281)
Acquisitions of and additions to real estate under development	(90,925)	(11,919)
Capital expenditures on rental properties	(16,196)	(10,697)
Acquisition of membership interest in co-investment	(41,513)	0
Proceeds from insurance for property losses	4,589	0
Proceeds from dispositions of real estate	74,485	14,123
Proceeds from dispositions of co-investments	11,072	0
Contributions to co-investments	(48,650)	(39,679)
Changes in restricted cash and refundable deposits	45,145	2,512
Purchases of marketable securities	(7,250)	(10,340)
Sales and maturities of marketable securities	717	4,016
Collections of notes and other receivables	0	35,500
Net cash used in investing activities	(286,856)	(60,590)
Cash flows from financing activities:
Borrowings under debt agreements	756,562	233,780
Repayment of debt	(536,830)	(312,585)
Additions to deferred charges	(4,456)	(9,294)
Net proceeds from issuance of common stock	174,592	157,596
Equity related issuance cost	0	(92)
Net proceeds from stock options exercises	15,613	1,176
Distributions to noncontrolling interest	(3,574)	(3,969)
Redemption of noncontrolling interest	(2,154)	(101)
Common and preferred stock dividends paid	(83,663)	(96,388)
Net cash provided by (used in) financing activities	316,090	(29,877)
Cash acquired in consolidation of co-investment	1,807	0
Net increase in cash and cash equivalents	193,590	1,427
Cash and cash equivalents at beginning of period	25,610	18,491
Cash and cash equivalents at end of period	219,200	19,918
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $4.3 million and $3.1 million capitalized in 2015 and 2014, respectively	50,343	26,447
Supplemental disclosure of noncash investing and financing activities:
Issuance of Operating Partnership units for contributed properties	0	1,419,816
Transfer from real estate under development to rental properties	162,345	3,070
Transfer from real estate under development to co-investments	1,562	3,125
Change in accrual of dividends	10,653	0
Change in fair value of marketable securities	1,934	1,575
Change in construction payable	2,139	376
Reclassifications of and changes in redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	1,660	0
Debt assumed in connection with acquisition of co-investment	114,435	0
Receivable for sales of common stock	9,566	440
Essex Portfolio, L.P. [Member]
Cash flows from operating activities:
Net income	64,753	26,406
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	106,907	50,312
Amortization of discount on marketable securities	(2,856)	(1,938)
Amortization of (premium) discount and debt financing costs, net	(6,530)	2,986
Gain on sale of marketable securities	0	(427)
Company's share of gain on the sales of co-investment	(469)	(3,211)
Earnings from co-investments	(3,842)	(7,315)
Company's/Operating Partnership's share of gain on the sales of co-investment	6,055	9,569
Gains on the sales of real estate and land	(7,112)	(7,481)
Non cash merger and integration expenses	0	3,750
Equity-based compensation	1,370	1,233
Gain on remeasurement of co-investment	(21,362)	0
Changes in operating assets and liabilities:
Prepaid expense, receivables and other assets	3,548	2,787
Accounts payable and accrued liabilities	21,741	15,131
Other liabilities	346	92
Net cash provided by operating activities	162,549	91,894
Additions to real estate:
Acquisitions of real estate	(199,190)	(33,825)
Redevelopment	(19,140)	(10,281)
Acquisitions of and additions to real estate under development	(90,925)	(11,919)
Capital expenditures on rental properties	(16,196)	(10,697)
Acquisition of membership interest in co-investment	(41,513)	0
Proceeds from insurance for property losses	4,589	0
Proceeds from dispositions of real estate	74,485	14,123
Proceeds from dispositions of co-investments	11,072	0
Contributions to co-investments	(48,650)	(39,679)
Changes in restricted cash and refundable deposits	45,145	2,512
Purchases of marketable securities	(7,250)	(10,340)
Sales and maturities of marketable securities	717	4,016
Collections of notes and other receivables	0	35,500
Net cash used in investing activities	(286,856)	(60,590)
Cash flows from financing activities:
Borrowings under debt agreements	756,562	233,780
Repayment of debt	(536,830)	(312,585)
Additions to deferred charges	(4,456)	(9,294)
Net proceeds from issuance of common stock	174,592	157,596
Equity related issuance cost	0	(92)
Net proceeds from stock options exercises	15,613	1,176
Distributions to noncontrolling interest	(221)	(1,335)
Redemption of noncontrolling interest	(2,154)	(101)
Common and preferred stock dividends paid	(87,016)	(99,022)
Net cash provided by (used in) financing activities	316,090	(29,877)
Cash acquired in consolidation of co-investment	1,807	0
Net increase in cash and cash equivalents	193,590	1,427
Cash and cash equivalents at beginning of period	25,610	18,491
Cash and cash equivalents at end of period	219,200	19,918
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $4.3 million and $3.1 million capitalized in 2015 and 2014, respectively	50,343	26,447
Supplemental disclosure of noncash investing and financing activities:
Issuance of Operating Partnership units for contributed properties	0	1,419,816
Transfer from real estate under development to rental properties	162,345	3,070
Transfer from real estate under development to co-investments	1,562	3,125
Change in accrual of dividends	10,653	0
Change in fair value of marketable securities	1,934	1,575
Change in construction payable	2,139	376
Reclassifications of and changes in redeemable noncontrolling interest from additional paid in capital and noncontrolling interest	1,660	0
Debt assumed in connection with acquisition of co-investment	114,435	0
Receivable for sales of common stock	$ 9,566	$ 440