v2.4.0.6
Covered Assets and FDIC Loss-sharing Asset (Narrative) (Details) (USD $)
 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Covered Assets And FDIC Loss Sharing Asset [Line Items]      
Payment Of Clawback If Losses Less Than Stated Levels, Period After Acquisition 10 years 45 days    
Percentage of Clawback 50.00%    
Percentage of stated threshold 20.00%    
Percentage of assets premium 25.00%    
Amount of estimated clawback liability $ 3,700,000 $ 0  
Provision (recapture) for loan and lease losses 5,752,000 47,346,000 63,500,000
Federal deposit insurance corporation loss-sharing indemnified assets 157,500,000 170,700,000  
Federal deposit insurance corporation loss-sharing indemnified assets receivable 17,600,000 35,300,000  
Maximum [Member]
      
Covered Assets And FDIC Loss Sharing Asset [Line Items]      
Loss Recovery Provision Effective Years 10 years    
Loss Sharing Agreement Effective Years 10 years    
Percentage of cumulative loss-sharing 25.00%    
Minimum [Member]
      
Covered Assets And FDIC Loss Sharing Asset [Line Items]      
Loss Recovery Provision Effective Years 8 years    
Loss Sharing Agreement Effective Years 5 years    
Percentage of cumulative loss-sharing 20.00%    
Covered Loans [Member]
      
Covered Assets And FDIC Loss Sharing Asset [Line Items]      
Percentage of loss shared by FDIC When Loss Share Thresholds Met   95.00%  
Percentage of loss shared by FDIC 80.00%    
FDIC Percentage Of Loss Recoveries 80.00% 95.00%  
Provision (recapture) for loan and lease losses (1,648,000) 6,055,000 0
Impairment expenses (589,000)    
Negative provision to adjust allowance for loss $ (1,000,000)