Significant Transactions (Details Textual) (USD $)	12 Months Ended					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 West Harlem Property Loans [Member]	Dec. 31, 2012 West Harlem Property Loans [Member] Units Property	Dec. 31, 2013 First Mortgage [Member] West Harlem Property Loans [Member]	Dec. 31, 2006 Second Mortgage [Member] West Harlem Property Loans [Member]
Noncontrolling Interest [Line Items]
Number of communities collateralizing notes receivable					84
Payments to Acquire Notes Receivable	$ 119,101,000	$ 0	$ 0			$ 119,100,000
Number Of Apartment Homes In Communities Collateralizing Notes Receivable					1,596
Number Of Commercial Spaces In Communities Collateralizing Notes Receivable					43
Aggregate Carrying Amount Of Second Mortgage Loans And Purchase Option					110,500,000
Mortgage Loans on Real Estate, Face Amount of Mortgages							100,100,000
Proceeds from repayment of first and second mortgage loans and unexercised option				$ 229,800,000