Borrowings (Textual) (Details) (USD $)
Dec. 31, 2014
subsidiary
Dec. 31, 2013
Dec. 31, 2012
Line of Credit Facility [Line Items]      
Short-term debt, weighted average interest rate 0.32% 0.29% 1.13%
Subordinated debt $ 46,393,000 $ 46,393,000  
Number of business trust subsidiaries, variable interest entities 3    
Investment in trust preferred securities subsidiaries, common stock owned 1,400,000    
Subordinated debt 45,000,000    
Floating rate 30-year capital securities with interest adjusted and paid quarterly at three-month LIBOR plus 3.10%, with a rate at December 31, 2014 and 2013, of 3.35%      
Line of Credit Facility [Line Items]      
Subordinated debt 15,464,000 15,464,000  
Floating rate 30-year capital securities with interest adjusted and paid quarterly at three-month LIBOR plus 1.89%, with a rate at December 31, 2014 and 2013, of 2.13%      
Line of Credit Facility [Line Items]      
Subordinated debt 10,310,000 10,310,000  
Floating rate 30-year capital securities with interest adjusted and paid quarterly at three-month LIBOR plus 1.40%, with rate at December 31, 2014 and 2013 of 1.64%      
Line of Credit Facility [Line Items]      
Subordinated debt 20,619,000 20,619,000  
Line of Credit      
Line of Credit Facility [Line Items]      
Remaining borrowing capacity 45,000,000 87,000,000  
Federal Home Loan Bank Borrowings | Line of Credit      
Line of Credit Facility [Line Items]      
Line of credit, maximum borrowing capacity $ 104,300,000 $ 119,600,000