Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Rental properties:
Land and land improvements	$ 2,505,257	$ 2,424,930
Buildings and improvements	9,332,472	8,819,751
Total rental properties	11,837,729	11,244,681
Less accumulated depreciation	(1,658,692)	(1,564,806)
Net real estate	10,179,037	9,679,875
Real estate under development	339,386	429,096
Co-investments	1,057,298	1,042,423
Real estate held for sale, net	0	56,300
Total real estate	11,575,721	11,207,694
Cash and cash equivalents-unrestricted	219,200	25,610
Cash and cash equivalents-restricted	36,030	70,139
Marketable securities and other investments	128,502	117,240
Notes and other receivables	28,954	24,923
Prepaid expenses and other assets	25,836	33,378
Acquired in place lease value	37,967	47,748
Deferred charges, net	32,949	29,439
Total assets	12,085,159	11,556,171
Liabilities and Equity
Mortgage notes payable	2,322,837	2,246,255
Unsecured debt	3,113,216	2,617,482
Lines of credit	0	246,391
Accounts payable and accrued liabilities	162,100	135,162
Construction payable	28,753	30,892
Dividends payable	98,874	88,221
Other liabilities	33,607	32,444
Total liabilities	5,759,387	5,396,847
Commitments and contingencies
Redeemable noncontrolling interest	24,916	23,256
Equity:
Common stock; $0.0001 par value, 656,020,000 shares authorized; 64,620,378 and 63,682,646 shares issued and outstanding, respectively	6	6
Cumulative redeemable 7.125% Series H preferred stock at liquidation value	73,750	73,750
Additional paid-in capital	6,848,255	6,651,165
Distributions in excess of accumulated earnings	(684,436)	(650,797)
Accumulated other comprehensive loss, net	(50,868)	(51,452)
Total stockholders' equity	6,186,707	6,022,672
Noncontrolling interest	114,149	113,396
Total equity	6,300,856	6,136,068
Total liabilities and equity	12,085,159	11,556,171
Essex Portfolio, L.P. [Member]
Rental properties:
Land and land improvements	2,505,257	2,424,930
Buildings and improvements	9,332,472	8,819,751
Total rental properties	11,837,729	11,244,681
Less accumulated depreciation	(1,658,692)	(1,564,806)
Net real estate	10,179,037	9,679,875
Real estate under development	339,386	429,096
Co-investments	1,057,298	1,042,423
Real estate held for sale, net	0	56,300
Total real estate	11,575,721	11,207,694
Cash and cash equivalents-unrestricted	219,200	25,610
Cash and cash equivalents-restricted	36,030	70,139
Marketable securities and other investments	128,502	117,240
Notes and other receivables	28,954	24,923
Prepaid expenses and other assets	25,836	33,378
Acquired in place lease value	37,967	47,748
Deferred charges, net	32,949	29,439
Total assets	12,085,159	11,556,171
Liabilities and Equity
Mortgage notes payable	2,322,837	2,246,255
Unsecured debt	3,113,216	2,617,482
Lines of credit	0	246,391
Accounts payable and accrued liabilities	162,100	135,162
Construction payable	28,753	30,892
Dividends payable	98,874	88,221
Other liabilities	33,607	32,444
Total liabilities	5,759,387	5,396,847
Commitments and contingencies
Redeemable noncontrolling interest	24,916	23,256
Equity:
General Partner	6,237,575	6,074,124
Limited Partners, Common equity	47,803	48,665
Accumulated other comprehensive loss, net	(48,757)	(49,356)
Total partners' capital	6,236,621	6,073,433
Noncontrolling interest	64,235	62,635
Total capital	6,300,856	6,136,068
Total liabilities and equity	12,085,159	11,556,171
Essex Portfolio, L.P. [Member] | General Partner [Member] | Common Capital [Member]
Equity:
General Partner	6,166,366	6,002,915
Total capital	6,166,366	6,002,915
Essex Portfolio, L.P. [Member] | General Partner [Member] | Preferred Capital [Member]
Equity:
General Partner	71,209	71,209
Total capital	$ 71,209	$ 71,209