Borrowings (Junior Subordinated Debentures) (Details) (USD $)
12 Months Ended 1 Months Ended 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Apr. 30, 2006
Dec. 31, 2006
Dec. 31, 2008
Junior Subordinated Debt [Member]            
Debt Instrument [Line Items]            
Interest expense on junior subordinated debentures $ 2,500,000 $ 2,500,000 $ 2,500,000      
Value of trust preferred securities included in Tier I Capital 43,000,000          
Percentage of trust preferred securities included in Tier I Capital ratio 17.30%          
Junior Subordinated Debt [Member] | Subsidiary One [Member]            
Debt Instrument [Line Items]            
Proceeds from issuance of trust preferred securities       36,100,000    
Value of outstanding common shares of subsidiary owned by company       1,100,000    
Debt instrument, interest rate       6.71%    
Debt instrument, interest rate terms       now floats at the 3 month LIBOR plus 140 basis points    
Debt interest rate, additional rate over three month LIBOR       1.40%    
Junior Subordinated Debt [Member] | Union Bankshares Capital Trust I [Member]            
Debt Instrument [Line Items]            
Value of outstanding common shares of subsidiary owned by company         248,000  
Debt instrument, interest rate terms         The interest rate of the trust preferred securities until April 7, 2011 was a blended rate equal to the sum of (1) the product of 50% times the average three-month LIBOR plus 1.42%, plus (2) the product of 50% times 6.4725%. The rate is now the average three-month LIBOR plus 1.42%.  
Debt interest rate, additional rate over three month LIBOR         1.42%  
Trust preferred securities assumed in acquisition           8,000,000
Aggregate amount of junior subordinated debt issued to subsidiary by acquired company, prior to acquisition         8,200,000  
Debt Instrument, Term         30 years  
Debt instrument fixed rate         6.4725%  
interest rate multiplier applied to variable rate         50.00%  
interest rate multiplier applied to fixed rate         50.00%  
Interest rate swaps            
Debt Instrument [Line Items]            
Notional amount of derivative $ 43,000,000 $ 43,000,000