Investments (Debt maturities) (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Available-for-sale Securities, Amortized Cost:    
One year or less $ 0  
After one year through five years 3,600  
After five years through ten years 0  
After ten years 47,699  
Subtotal 51,299  
Total securities 284,158  
Available-for-sale Securities, Fair Value:    
One year or less 0  
After one year through five years 3,767  
After five years through ten years 0  
After ten years 50,150  
Subtotal 53,917  
Fair Value/ Carrying Value 290,311 219,039
Held-to-maturity Securities, Amortized Cost:    
One year or less 504  
After one year through five years 1,856  
After five years through ten years 8,040  
After ten years 4,443  
Subtotal 14,843  
Total securities 14,843 16,143
Held-to-maturity Securities, Fair Value:    
One year or less 520  
After one year through five years 2,002  
After five years through ten years 8,868  
After ten years 5,057  
Subtotal 16,447  
Fair Value 16,447  
Mortgage-backed securities
    
Available-for-sale Securities, Amortized Cost:    
No single maturity date 212,055  
Available-for-sale Securities, Fair Value:    
No single maturity 215,271  
Held-to-maturity Securities, Amortized Cost:    
No single maturity date 0  
Held-to-maturity Securities, Fair Value:    
No single maturity date 0  
SBA Pools
    
Available-for-sale Securities, Amortized Cost:    
No single maturity date 20,804  
Available-for-sale Securities, Fair Value:    
No single maturity 21,123  
Fair Value/ Carrying Value 21,123  
Held-to-maturity Securities, Amortized Cost:    
No single maturity date 0  
Held-to-maturity Securities, Fair Value:    
No single maturity date $ 0