Investment securities (Available For Sale Securities Continuous Unrealized Loss Position Fair Value) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Available-for-sale    
Estimated fair value, Less than 12 months $ 40,478 $ 45,712
Unrealized losses, Less than 12 months (243) (1,226)
Estimated fair value, 12 months or more 49,472 32,733
Unrealized losses, 12 months or more (1,102) (2,855)
Estimated fair value, Total 89,950 78,445
Unrealized losses, Total (1,345) (4,081)
Held-to-maturity    
Eestimated fair value, Less than 12 months 3,806  
Unrealized losses, Less than 12 months (18)  
Estimated fair value, 12 months or more 0  
Unrealized losses, 12 months or more 0  
Estimated fair value, Total 3,806  
Unrealized losses, Total (18)  
U.S. Agency (MBS)    
Available-for-sale    
Estimated fair value, Less than 12 months 15,807 35,440
Unrealized losses, Less than 12 months (17) (810)
Estimated fair value, 12 months or more 41,479 30,779
Unrealized losses, 12 months or more (879) (2,836)
Estimated fair value, Total 57,286 66,219
Unrealized losses, Total (896) (3,646)
Non-agency MBS    
Available-for-sale    
Estimated fair value, Less than 12 months 23,953 9,569
Unrealized losses, Less than 12 months (220) (412)
Estimated fair value, 12 months or more 6,411 179
Unrealized losses, 12 months or more (187) (2)
Estimated fair value, Total 30,364 9,748
Unrealized losses, Total (407) (414)
U.S. Agency asset-backed securities    
Available-for-sale    
Estimated fair value, Less than 12 months 718 703
Unrealized losses, Less than 12 months (6) (4)
Estimated fair value, 12 months or more 1,582 1,775
Unrealized losses, 12 months or more (36) (17)
Estimated fair value, Total 2,300 2,478
Unrealized losses, Total (42) (21)
Obligations of state and political subdivisions    
Held-to-maturity    
Eestimated fair value, Less than 12 months 3,806  
Unrealized losses, Less than 12 months (18)  
Estimated fair value, 12 months or more 0  
Unrealized losses, 12 months or more 0  
Estimated fair value, Total 3,806  
Unrealized losses, Total $ (18)