Summary of Critical and Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 Community Partnership	Dec. 31, 2012	Dec. 31, 2011
Principles of Consolidation [Abstract]
Noncontrolling interest in Operating Partnership (in hundredths)	5.40%	5.50%
Number of DownREIT limited partnerships the company consolidates	19
Number of communities within the DownREIT partnership	11
Assets related to variable interest entities, net intercompany eliminations	$ 194,900,000	$ 201,100,000
Liabilities related to variable interest entities, net of intercompany eliminations	178,300,000	178,600,000
Redemption rights of limited partners by issuance of common stock for partnership unit, conversion basis	one share per unit basis
Total DownREIT units outstanding (in shares)	1,007,879	1,039,431
Redemption value of the variable interest entities	144,600,000	152,400,000
Real Estate Rental Properties [Abstract]
Threshold useful life of assets for capitalization	1 year
Depreciable life of various categories of fixed assets [Abstract]
Expected lease term of acquired tenant	20 months
Revenues and Gains on Sale of Real Estate [Abstract]
Lease terms, minimum	6 months
Lease terms, maximum	12 months
No rent time period, minimum	1 month
No rent time period, maximum	2 months
Cash Equivalents and Restricted Cash [Abstract]
Original maturities of highly liquid investments to be classified as cash equivalents, maximum	3 months
Marketable Securities [Abstract]
Maturity date of investments in mortgage backed securities, first	November 2019	November 2019
Maturity date of investments in mortgage backed securities, final	September 2020	September 2020
Proceeds from sales of available for sale securities	24,200,000	61,700,000	33,000,000
Gain from sales of available-for-sale securities	1,800,000	800,000	5,000,000
Capitalization Policy [Abstract]
Capitalized internal costs related to development and redevelopment projects	7,500,000	6,200,000	4,300,000
Capitalized salaries	2,600,000	2,400,000	2,200,000
Fair Value of Financial Instruments [Abstract]
Fixed rate debt carrying amount	2,300,000,000	2,130,000,000
Fixed rate debt fair value	2,330,000,000	2,240,000,000
Variable rate debt, carrying amount	737,000,000	692,900,000
Variable rate debt fair value	719,400,000	671,700,000
Mortgage backed securities carrying value	58,700,000
Mortgage backed securities fair value	83,800,000
Schedule of Available-for-sale Securities [Line Items]
Total Amortized Cost	90,876,000	90,182,000
Total Gross Unrealized Gain (Loss)	(792,000)	2,531,000
Total Fair Value	90,084,000	92,713,000
Interest income	9,114,000	10,715,000	10,501,000
Co-investment promote fee	0	2,299,000	0
Gains on sales of marketable securities	2,519,000	819,000	4,956,000
Tax benefit - Taxable REIT Subsidiary	0	0	1,682,000
Total interest and other income	11,633,000	13,833,000	17,139,000
Statement [Line Items]
Balance at beginning	(71,658,000)
Other comprehensive income (loss) before reclassification, derivative	3,468,000
Amounts reclassified from accumulated other comprehensive loss	8,466,000
Net other comprehensive income (loss)	11,934,000
Balance at the end	(59,724,000)	(71,658,000)
Unrealized gains/(losses) on available for sale securities [Abstract]
Balance at beginning	2,397,000
Other comprehensive income (loss) before reclassification, available for sale securities, total	(1,472,000)
Amounts reclassified from accumulated other comprehensive loss	(1,673,000)
Net other comprehensive income (loss)	(3,145,000)
Balance at the end	(748,000)	2,397,000
Accumulated other comprehensive loss, net by component [Abstract]
Balance at beginning	(69,261,000)
Other comprehensive income (loss) before reclassification	1,996,000
Amounts reclassified from accumulated other comprehensive loss	6,793,000
Net other comprehensive income (loss)	8,789,000
Balance at the end	(60,472,000)	(69,261,000)
Essex Portfolio, L.P. [Member]
Schedule of Available-for-sale Securities [Line Items]
Total interest and other income	11,633,000	13,833,000	17,139,000
Statement [Line Items]
Balance at beginning	(70,762,000)
Other comprehensive income (loss) before reclassification, derivative	4,148,000
Amounts reclassified from accumulated other comprehensive loss	8,466,000
Net other comprehensive income (loss)	12,614,000
Balance at the end	(58,148,000)	(70,762,000)
Unrealized gains/(losses) on available for sale securities [Abstract]
Balance at beginning	2,531,000
Other comprehensive income (loss) before reclassification, available for sale securities, total	(1,556,000)
Amounts reclassified from accumulated other comprehensive loss	(1,767,000)
Net other comprehensive income (loss)	(3,323,000)
Balance at the end	(792,000)	2,531,000
Accumulated other comprehensive loss, net by component [Abstract]
Balance at beginning	(68,231,000)
Other comprehensive income (loss) before reclassification	2,592,000
Amounts reclassified from accumulated other comprehensive loss	6,699,000
Net other comprehensive income (loss)	9,291,000
Balance at the end	(58,940,000)	(68,231,000)
Investment-grade unsecured bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,446,000	15,475,000
Gross Unrealized Gain (Loss)	509,000	826,000
Carrying Value	15,955,000	16,301,000
Investment funds-US treasuries [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,675,000	3,788,000
Gross Unrealized Gain (Loss)	3,000	1,000
Carrying Value	3,678,000	3,789,000
Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13,104,000	18,917,000
Gross Unrealized Gain (Loss)	(1,304,000)	1,704,000
Carrying Value	11,800,000	20,621,000
Mortgage backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	58,651,000	52,002,000
Gross Unrealized Gain (Loss)	0	0
Carrying Value	$ 58,651,000	$ 52,002,000
Common Stock [Member]
Status of cash dividends distributed [Abstract]
Ordinary income (in hundredths)	77.34%	70.58%	63.68%
Capital gains (in hundredths)	17.64%	8.75%	11.16%
Unrecaptured section 1250 capital gain (in hundredths)	5.02%	7.97%	0.74%
Return of capital (in hundredths)	0.00%	12.70%	24.42%
Total cash dividends distributed (in hundredths)	100.00%	100.00%	100.00%
Series F, G and H Preferred Stock [Member]
Status of cash dividends distributed [Abstract]
Ordinary income (in hundredths)	77.34%	80.85%	100.00%
Capital gains (in hundredths)	17.64%	10.02%	0.00%
Unrecaptured section 1250 capital gain (in hundredths)	5.02%	9.13%	0.00%
Total cash dividends distributed (in hundredths)	100.00%	100.00%	100.00%
Computer Software and Equipment [Member] | Minimum [Member]
Depreciable life of various categories of fixed assets [Abstract]
Depreciable life, average	3 years
Computer Software and Equipment [Member] | Maximum [Member]
Depreciable life of various categories of fixed assets [Abstract]
Depreciable life, average	5 years
Interior Unit Improvements [Member]
Depreciable life of various categories of fixed assets [Abstract]
Depreciable life, average	5 years
Land Improvements and Certain Exterior Components of Real Property [Member]
Depreciable life of various categories of fixed assets [Abstract]
Depreciable life, average	10 years
Real Estate Structures [Member]
Depreciable life of various categories of fixed assets [Abstract]
Depreciable life, average	30 years