Deposits (Details) (USD $)
Dec. 31, 2014
Dec. 31, 2013
Deposits    
Demand deposits, non-interest-bearing $ 666,607,000 $ 547,531,000
Interest-bearing transaction deposits 67,774,000 61,384,000
Savings deposits 210,673,000 206,587,000
Money market deposits 1,459,723,000 1,471,265,000
Time deposits 496,071,000 582,371,000
Total deposits 2,900,848,000 2,869,138,000
Time deposits minimum denomination of $100,000 or more 138,400,000 163,700,000
Time deposits minimum denomination of $250,000 or more 24,400,000 28,800,000
Brokered and National included in the balance of time deposits 500,000  
Deposits    
2015 309,598,000  
2016 95,118,000  
2017 61,161,000  
2018 18,934,000  
2019 11,250,000  
Thereafter 10,000  
Total $ 496,071,000 $ 582,371,000