v2.4.0.8
Fair Value Measurements - Financial Instruments Measured at Fair Value on a Recurring Basis (Details) (USD $)
In Thousands, unless otherwise specified
9 Months Ended
Sep. 30, 2013
Dec. 31, 2012
Assets    
Securities available for sale $ 453,046 $ 640,212
State tax credits held for sale 20,139 23,020
Liabilities    
State tax credits, held for sale 55,810 61,284
Tax credit stream, term 10 years  
Years of tax credits generated 10 years  
Obligations of U.S. Government sponsored enterprises
   
Assets    
Securities available for sale 93,974 152,368
Obligations of states and political subdivisions
   
Assets    
Securities available for sale 51,193 53,003
Residential mortgage-backed securities
   
Assets    
Securities available for sale 307,879 434,841
Quoted Prices in Active Markets for Identical Assets (Level 1)
   
Assets    
State tax credits held for sale 0 0
Significant Other Observable Inputs (Level 2)
   
Assets    
State tax credits held for sale 0 0
Significant Unobservable Inputs (Level 3)
   
Assets    
State tax credits held for sale 40,798 43,802
Significant Unobservable Inputs (Level 3) | Auction Rate Securities
   
Liabilities    
Number of securities 3  
Total Fair Value
   
Assets    
State tax credits held for sale 40,798 43,802
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
   
Assets    
Securities available for sale 0  
State tax credits held for sale 0  
Derivative financial instruments 0  
Total assets 0  
Liabilities    
Derivative financial instruments 0  
Total liabilities 0  
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Obligations of U.S. Government sponsored enterprises
   
Assets    
Securities available for sale 0  
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Obligations of states and political subdivisions
   
Assets    
Securities available for sale 0  
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities
   
Assets    
Securities available for sale 0  
Recurring basis | Significant Other Observable Inputs (Level 2)
   
Assets    
Securities available for sale 450,004  
State tax credits held for sale 0  
Derivative financial instruments 1,128  
Total assets 451,132  
Liabilities    
Derivative financial instruments 1,114  
Total liabilities 1,114  
Recurring basis | Significant Other Observable Inputs (Level 2) | Obligations of U.S. Government sponsored enterprises
   
Assets    
Securities available for sale 93,974  
Recurring basis | Significant Other Observable Inputs (Level 2) | Obligations of states and political subdivisions
   
Assets    
Securities available for sale 48,151  
Recurring basis | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities
   
Assets    
Securities available for sale 307,879  
Recurring basis | Significant Unobservable Inputs (Level 3)
   
Assets    
Securities available for sale 3,042  
State tax credits held for sale 20,139  
Derivative financial instruments 0  
Total assets 23,181  
Liabilities    
Derivative financial instruments 0  
Total liabilities 0  
Recurring basis | Significant Unobservable Inputs (Level 3) | Obligations of U.S. Government sponsored enterprises
   
Assets    
Securities available for sale 0  
Recurring basis | Significant Unobservable Inputs (Level 3) | Obligations of states and political subdivisions
   
Assets    
Securities available for sale 3,042  
Recurring basis | Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities
   
Assets    
Securities available for sale 0  
Recurring basis | Total Fair Value
   
Assets    
Securities available for sale 453,046  
State tax credits held for sale 20,139  
Derivative financial instruments 1,128  
Total assets 474,313  
Liabilities    
Derivative financial instruments 1,114  
Total liabilities 1,114  
Recurring basis | Total Fair Value | Obligations of U.S. Government sponsored enterprises
   
Assets    
Securities available for sale 93,974  
Recurring basis | Total Fair Value | Obligations of states and political subdivisions
   
Assets    
Securities available for sale 51,193  
Recurring basis | Total Fair Value | Residential mortgage-backed securities
   
Assets    
Securities available for sale 307,879  
Portion at Fair Value, Fair Value Disclosure | Recurring basis | Total Fair Value
   
Assets    
State tax credits held for sale 20,100  
Portion at Other than Fair Value, Fair Value Disclosure
   
Assets    
State tax credits held for sale $ 35,700  
LIBOR Swap Curve
   
Liabilities    
Discount rate, basis point spread 205