Significant Transactions During the First Quarter of 2013 and Subsequent Events (Details) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2013 Unit	Jun. 30, 2012	Jun. 30, 2013 Unit	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]	May 30, 2013 Regency at Mountain View [Member] Unit	May 30, 2013 Gas Company Lofts [Member] Unit
Acquisitions [Abstract]
Cost of acquired entity								$ 42,500,000	$ 71,000,000
Number of units	222		222					142	251
Dispositions [Abstract]
Sale of land held for future development	244,000,000						26,400,000
Ownership percentage in Fund II							28.20%	50.00%
Number of units disposed of	222		222					142	251
Gain on sale of land	0	0	1,503,000	0			2,400,000
Penalty paid on repayment of debt							200,000
Sale of land, subsequent event	244,000,000						26,400,000
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)