Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Related Party Transactions [Abstract]
Management and other fees from affiliates including management, property management, development and redevelopment fees from co-investments, net of intercompany amounts eliminated by company	$ 2.4	$ 1.2
Essex Skyline at MacArthrur Place [Member]
Related Party Transaction [Line Items]
Executive Vice President of the Company invested	$ 4.0
Limited partnership interest in partnership investments (in hundredths)	6.00%
Invested company's interest in a limited liability company that acquired Essex Skyline at MacArthur (in hundredths)	50.00%