Fair Value Measurements Narrative (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 12 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2012
Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair Value Inputs, Market Risk Premium     25.00%  
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount     $ 32,243  
Asset, Level 2 to Level 1 transfers     2,735  
Impaired loan recorded investment     2,915 [1] 3,789
Loans guaranteed     2,328 2,354
Write-offs against allowance for loan losses $ 1 $ 1,589    
Fair Value Measurements, EBITDA Multiple     3  
[1] $2,328 is guaranteed by the USDA or SBA.