Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Rental properties:
Land and land improvements	$ 2,710,139	$ 2,719,064
Buildings and improvements	10,693,682	10,639,108
Total rental properties	13,403,821	13,358,172
Less: accumulated depreciation	(2,992,819)	(2,769,297)
Net real estate	10,411,002	10,588,875
Real estate under development	343,841	355,735
Co-investments	1,291,320	1,155,984
Total real estate	12,046,163	12,100,594
Cash and cash equivalents-unrestricted	160,902	44,620
Cash and cash equivalents-restricted	16,674	16,506
Marketable securities	207,191	190,004
Notes and other receivables (includes related party receivables of $10.8 million and $41.2 million as of June 30, 2018 and December 31, 2017, respectively)	68,386	100,926
Prepaid expenses and other assets	56,338	43,056
Total assets	12,555,654	12,495,706
LIABILITIES AND EQUITY/CAPITAL
Unsecured debt, net	3,798,097	3,501,709
Mortgage notes payable, net	1,890,326	2,008,417
Lines of credit	2,670	179,000
Accounts payable and accrued liabilities	132,796	127,501
Construction payable	58,321	51,770
Dividends/Distributions payable	129,007	121,420
Distributions in excess of investments in co-investments	0	36,726
Other liabilities	33,497	33,132
Total liabilities	6,044,714	6,059,675
Commitments and contingencies
Redeemable noncontrolling interest	36,257	39,206
Equity/Capital:
Common stock; $0.0001 par value, 670,000,000 shares authorized; 66,049,618 and 66,054,399 shares issued and outstanding, respectively	7	7
Additional paid-in capital	7,131,809	7,129,571
Distributions in excess of accumulated earnings	(766,193)	(833,726)
Limited Partners:
Accumulated other comprehensive loss, net	(11,438)	(18,446)
Total stockholders' equity	6,354,185	6,277,406
Noncontrolling interest	120,498	119,419
Total equity	6,474,683	6,396,825
Total liabilities and equity/capital	12,555,654	12,495,706
Essex Portfolio, L.P. [Member]
Rental properties:
Land and land improvements	2,710,139	2,719,064
Buildings and improvements	10,693,682	10,639,108
Total rental properties	13,403,821	13,358,172
Less: accumulated depreciation	(2,992,819)	(2,769,297)
Net real estate	10,411,002	10,588,875
Real estate under development	343,841	355,735
Co-investments	1,291,320	1,155,984
Total real estate	12,046,163	12,100,594
Cash and cash equivalents-unrestricted	160,902	44,620
Cash and cash equivalents-restricted	16,674	16,506
Marketable securities	207,191	190,004
Notes and other receivables (includes related party receivables of $10.8 million and $41.2 million as of June 30, 2018 and December 31, 2017, respectively)	68,386	100,926
Prepaid expenses and other assets	56,338	43,056
Total assets	12,555,654	12,495,706
LIABILITIES AND EQUITY/CAPITAL
Unsecured debt, net	3,798,097	3,501,709
Mortgage notes payable, net	1,890,326	2,008,417
Lines of credit	2,670	179,000
Accounts payable and accrued liabilities	132,796	127,501
Construction payable	58,321	51,770
Dividends/Distributions payable	129,007	121,420
Distributions in excess of investments in co-investments	0	36,726
Other liabilities	33,497	33,132
Total liabilities	6,044,714	6,059,675
Commitments and contingencies
Redeemable noncontrolling interest	36,257	39,206
Limited Partners:
Common equity (2,272,983 and 2,268,114 units issued and outstanding, respectively)	52,339	49,792
Accumulated other comprehensive loss, net	(7,898)	(15,229)
Total partners' capital	6,410,064	6,330,415
Noncontrolling interest	64,619	66,410
Total capital	6,474,683	6,396,825
Total liabilities and equity/capital	12,555,654	12,495,706
Essex Portfolio, L.P. [Member] | General Partner [Member]
General Partner:
Common equity (66,049,618 and 66,054,399 units issued and outstanding, respectively)	6,365,623	6,295,852
Essex Portfolio, L.P. [Member] | General Partner [Member] | Common Equity [Member]
General Partner:
Common equity (66,049,618 and 66,054,399 units issued and outstanding, respectively)	6,365,623	6,295,852
Limited Partners:
Total capital	$ 6,365,623	$ 6,295,852