Real Estate Investments Acquisitions And Sales Of Real Estate (Details) $ in Millions	1 Months Ended		12 Months Ended
	Apr. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) community unit	Dec. 31, 2014 USD ($) community unit
Schedule of Equity Method Investments [Line Items]
Purchase Price			$ 638.1
Land and Land Improvements [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price			117.9
Building and Building Improvements [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price			513.3
Leases, Acquired-in-Place [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price			5.3
Prepaid Expenses and Other Current Assets [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price			$ 1.6
Apartment Building [Member]
Schedule of Equity Method Investments [Line Items]
Number of businesses acquired | community			7	6
Number of units acquired | unit			1,722	1,480
Purchase Price			$ 638.1	$ 460.7
Eighth And Hope [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit			290
Purchase Price			$ 200.0
Essex Ownership Percentage			100.00%
The Huxley [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit			187
Purchase Price			$ 48.8
Essex Ownership Percentage			100.00%
The Dylan [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit			184
Purchase Price			$ 51.3
Essex Ownership Percentage			100.00%
The Reveal [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit			438
Purchase Price	$ 73.0		$ 73.0
Essex Ownership Percentage			99.75%
Ownership percentage by partners	49.50%
Avant [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit			247
Purchase Price			$ 99.0
Essex Ownership Percentage			100.00%
Avant II [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit			193
Purchase Price			$ 73.0
Essex Ownership Percentage			100.00%
Enso [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit			183
Purchase Price			$ 93.0
Essex Ownership Percentage			100.00%
The Huxley And The Dylan [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price		$ 100.1