Significant Transactions During the First Quarter of 2013 and Subsequent Events (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Secured Debt [Member]	Jun. 30, 2013 Mello Roos Bonds [Member]	Jun. 30, 2013 Essex Apartment Value Fund II, LP [Member] Unit	Jun. 30, 2013 Essex Apartment Value Fund II, LP [Member] Subsequent Event [Member]	May 30, 2013 Regency at Mountain View [Member] Unit	Jun. 30, 2013 Gas Company Lofts [Member] Unit
Acquisitions [Abstract]
Cost of acquired entity									$ 42,500,000	$ 71,000,000
Number of units							222		142	251
Dispositions [Abstract]
Ownership percentage in Fund II							28.20%		50.00%
Sale of land held for future development							26,400,000	244,000,000
Number of units disposed of							222		142	251
Penalty paid on repayment of debt							200,000
Sale of land, subsequent event							26,400,000	244,000,000
Secured Debt [Abstract]
Early extinguishment of debt					27,300,000	14,200,000
(Gain) loss on early retirement of debt	(1,024,000)	1,450,000	(1,024,000)	1,450,000	200,000	1,500,000
Line of Credit Facility, Remaining Borrowing Capacity	621,000,000		621,000,000
Structured Financing [Abstract]
Cash proceeds from redemption of preferred equity investment			13,100,000
Early redemption of investment penalty			$ 500,000