Investments In Unconsolidated Joint Ventures (Red Bank Corporate Plaza) (Details) (Red Bank Corporate Plaza [Member], USD $)
0 Months Ended 1 Months Ended 12 Months Ended
Sep. 22, 2011
May 31, 2011
Dec. 31, 2011
sqft
Dec. 31, 2010
Dec. 31, 2009
Schedule of Equity Method Investments [Line Items]          
Percentage of interest in venture     50.00%    
Mortgage loans, carrying amount   $ 20,300,000      
New mortgage loan     18,100,000    
Fixed interest rate 3.99375%        
Mortgage loan, maturity date     May 17, 2016    
Repayment of mortgage loan   1,700,000      
Area of office property     92,878    
Spread over LIBOR     300    
LIBOR interest rate     0.29%    
Percentage of loan principal swapped 75.00%        
Management, leasing and other services fees     $ 100,000 $ 91,000 $ 92,600
Previous Mortgage Loan [Member]
         
Schedule of Equity Method Investments [Line Items]          
Spread over LIBOR     125