Real Estate Investments Real Estate Investments - Acquisitions And Sales Of Real Estate (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) community unit	Dec. 31, 2015 USD ($) community unit
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit	753
Purchase Price	$ 333.7
Land and Land Improvements [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price	72.4
Building and Building Improvements [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price	259.3
Leases, Acquired-in-Place [Member]
Schedule of Equity Method Investments [Line Items]
Purchase Price	$ 2.0
Mio Apartment Community [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit	103
Purchase Price	$ 51.3
Essex Ownership Percentage	100.00%
Form 15 [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit	242
Purchase Price	$ 97.4
Essex Ownership Percentage	100.00%
Emerson Valley Village [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit	144
Purchase Price	$ 67.0
Essex Ownership Percentage	100.00%
Ashton Sherman Village [Member]
Schedule of Equity Method Investments [Line Items]
Number of units acquired | unit	264
Purchase Price	$ 118.0
Essex Ownership Percentage	100.00%
Apartment Building [Member]
Schedule of Equity Method Investments [Line Items]
Number of communities acquired | community	4	7
Number of units acquired | unit	753	1,722
Purchase Price	$ 333.7	$ 638.1