Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Rental properties:
Land and land improvements	$ 2,710,139	$ 2,719,064
Buildings and improvements	10,744,841	10,643,009
Total rental properties	13,454,980	13,362,073
Less: accumulated depreciation	(3,113,386)	(2,769,297)
Net real estate	10,341,594	10,592,776
Real estate under development	403,644	355,735
Co-investments	1,267,593	1,155,984
Total real estate	12,012,831	12,104,495
Cash and cash equivalents-unrestricted	157,279	44,620
Cash and cash equivalents-restricted	17,347	16,506
Marketable securities	210,596	190,004
Notes and other receivables (includes related party receivables of $10.3 million and $41.2 million as of September 30, 2018 and December 31, 2017, respectively)	69,166	100,926
Prepaid expenses and other assets	50,924	39,155
Total assets	12,518,143	12,495,706
LIABILITIES AND EQUITY/CAPITAL
Unsecured debt, net	3,798,705	3,501,709
Mortgage notes payable, net	1,834,967	2,008,417
Lines of credit	0	179,000
Accounts payable and accrued liabilities	185,426	127,501
Construction payable	63,905	51,770
Dividends/Distributions payable	128,831	121,420
Distributions in excess of investments in co-investments	0	36,726
Other liabilities	33,616	33,132
Total liabilities	6,045,450	6,059,675
Commitments and contingencies
Redeemable noncontrolling interest	36,665	39,206
Equity/Capital:
Common stock; $0.0001 par value, 670,000,000 shares authorized; 66,055,166 and 66,054,399 shares issued and outstanding, respectively	7	7
Additional paid-in capital	7,133,587	7,129,571
Distributions in excess of accumulated earnings	(808,085)	(833,726)
Limited Partners:
Accumulated other comprehensive loss, net	(8,548)	(18,446)
Total stockholders' equity	6,316,961	6,277,406
Noncontrolling interest	119,067	119,419
Total equity	6,436,028	6,396,825
Total liabilities and equity/capital	12,518,143	12,495,706
Essex Portfolio, L.P. [Member]
Rental properties:
Land and land improvements	2,710,139	2,719,064
Buildings and improvements	10,744,841	10,643,009
Total rental properties	13,454,980	13,362,073
Less: accumulated depreciation	(3,113,386)	(2,769,297)
Net real estate	10,341,594	10,592,776
Real estate under development	403,644	355,735
Co-investments	1,267,593	1,155,984
Total real estate	12,012,831	12,104,495
Cash and cash equivalents-unrestricted	157,279	44,620
Cash and cash equivalents-restricted	17,347	16,506
Marketable securities	210,596	190,004
Notes and other receivables (includes related party receivables of $10.3 million and $41.2 million as of September 30, 2018 and December 31, 2017, respectively)	69,166	100,926
Prepaid expenses and other assets	50,924	39,155
Total assets	12,518,143	12,495,706
LIABILITIES AND EQUITY/CAPITAL
Unsecured debt, net	3,798,705	3,501,709
Mortgage notes payable, net	1,834,967	2,008,417
Lines of credit	0	179,000
Accounts payable and accrued liabilities	185,426	127,501
Construction payable	63,905	51,770
Dividends/Distributions payable	128,831	121,420
Distributions in excess of investments in co-investments	0	36,726
Other liabilities	33,616	33,132
Total liabilities	6,045,450	6,059,675
Commitments and contingencies
Redeemable noncontrolling interest	36,665	39,206
Limited Partners:
Common equity (2,272,983 and 2,268,114 units issued and outstanding, respectively)	51,093	49,792
Accumulated other comprehensive loss, net	(4,908)	(15,229)
Total partners' capital	6,371,694	6,330,415
Noncontrolling interest	64,334	66,410
Total capital	6,436,028	6,396,825
Total liabilities and equity/capital	12,518,143	12,495,706
Essex Portfolio, L.P. [Member] | General Partner [Member]
General Partner:
Common equity (66,055,166 and 66,054,399 units issued and outstanding, respectively)	6,325,509	6,295,852
Essex Portfolio, L.P. [Member] | General Partner [Member] | Common Equity [Member]
General Partner:
Common equity (66,055,166 and 66,054,399 units issued and outstanding, respectively)	6,325,509	6,295,852
Limited Partners:
Total capital	$ 6,325,509	$ 6,295,852