Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Rental properties:
Land and land improvements	$ 2,719,064	$ 2,719,064
Buildings and improvements	10,657,671	10,629,767
Total rental properties	13,376,735	13,348,831
Less: accumulated depreciation	(2,888,130)	(2,769,297)
Net real estate	10,488,605	10,579,534
Real estate under development	395,710	355,735
Co-investments	1,290,957	1,155,984
Total real estate	12,175,272	12,091,253
Cash and cash equivalents-unrestricted	121,954	44,620
Cash and cash equivalents-restricted	17,124	16,506
Marketable securities	197,745	190,004
Notes and other receivables (includes related party receivables of $9.9 million and $41.2 million as of March 31, 2018 and December 31, 2017, respectively)	70,525	100,926
Prepaid expenses and other assets	60,047	52,397
Total assets	12,642,667	12,495,706
LIABILITIES AND EQUITY/CAPITAL
Unsecured debt, net	3,797,923	3,501,709
Mortgage notes payable, net	1,921,047	2,008,417
Lines of credit	0	179,000
Accounts payable and accrued liabilities	179,641	127,501
Construction payable	48,223	51,770
Dividends/Distributions payable	129,038	121,420
Distributions in excess of investments in co-investments	0	36,726
Other liabilities	33,477	33,132
Total liabilities	6,109,349	6,059,675
Commitments and contingencies
Redeemable noncontrolling interest	41,159	39,206
Equity/Capital:
Common stock; $0.0001 par value, 670,000,000 shares authorized; 66,044,441 and 66,054,399 shares issued and outstanding, respectively	7	7
Additional paid-in capital	7,127,248	7,129,571
Distributions in excess of accumulated earnings	(743,773)	(833,726)
Limited Partners:
Accumulated other comprehensive loss, net	(14,709)	(18,446)
Total stockholders' equity	6,368,773	6,277,406
Noncontrolling interest	123,386	119,419
Total equity	6,492,159	6,396,825
Total liabilities and equity/capital	12,642,667	12,495,706
Essex Portfolio, L.P. [Member]
Rental properties:
Land and land improvements	2,719,064	2,719,064
Buildings and improvements	10,657,671	10,629,767
Total rental properties	13,376,735	13,348,831
Less: accumulated depreciation	(2,888,130)	(2,769,297)
Net real estate	10,488,605	10,579,534
Real estate under development	395,710	355,735
Co-investments	1,290,957	1,155,984
Total real estate	12,175,272	12,091,253
Cash and cash equivalents-unrestricted	121,954	44,620
Cash and cash equivalents-restricted	17,124	16,506
Marketable securities	197,745	190,004
Notes and other receivables (includes related party receivables of $9.9 million and $41.2 million as of March 31, 2018 and December 31, 2017, respectively)	70,525	100,926
Prepaid expenses and other assets	60,047	52,397
Total assets	12,642,667	12,495,706
LIABILITIES AND EQUITY/CAPITAL
Unsecured debt, net	3,797,923	3,501,709
Mortgage notes payable, net	1,921,047	2,008,417
Lines of credit	0	179,000
Accounts payable and accrued liabilities	179,641	127,501
Construction payable	48,223	51,770
Dividends/Distributions payable	129,038	121,420
Distributions in excess of investments in co-investments	0	36,726
Other liabilities	33,477	33,132
Total liabilities	6,109,349	6,059,675
Commitments and contingencies
Redeemable noncontrolling interest	41,159	39,206
Limited Partners:
Common equity (2,273,413 and 2,268,114 units issued and outstanding, respectively)	53,003	49,792
Accumulated other comprehensive loss, net	(11,281)	(15,229)
Total partners' capital	6,425,204	6,330,415
Noncontrolling interest	66,955	66,410
Total capital	6,492,159	6,396,825
Total liabilities and equity/capital	12,642,667	12,495,706
Essex Portfolio, L.P. [Member] | General Partner [Member]
General Partner:
Common equity (66,044,441 and 66,054,399 units issued and outstanding, respectively)	6,383,482	6,295,852
Essex Portfolio, L.P. [Member] | General Partner [Member] | Common Equity [Member]
General Partner:
Common equity (66,044,441 and 66,054,399 units issued and outstanding, respectively)	6,383,482	6,295,852
Limited Partners:
Total capital	$ 6,383,482	$ 6,295,852