Variable Interest Entities (VIE) (Narrative) (Details) (USD $)
9 Months Ended
Sep. 30, 2012
Dec. 31, 2011
Variable Interest Entity [Line Items]    
Long-term Debt $ 182,750,000 $ 207,044,000
VIE purpose purchase the land and construct a 36-unit low income housing rental complex  
Federal investment tax credits 8,600,000  
Federal investment tax credit duration 10-year  
Variable Interest Entity, Not Primary Beneficiary [Member]
   
Variable Interest Entity [Line Items]    
Long-term Debt 41,700,000  
Equity Method Investments 1,300,000  
Ownership in Liberty Mews Limited Partnership 99.99%  
VIE financing 10,600,000  
Construction and Development Costs 10,600,000  
Partnership total assets 10,100,000 10,900,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Junior Subordinated Debt [Member]
   
Variable Interest Entity [Line Items]    
Long-term Debt 5,000,000  
Issuance of Equity [Member]
   
Variable Interest Entity [Line Items]    
VIE financing $ 6,100,000