Business Combination - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Nov. 01, 2013
Business Acquisition [Line Items]      
Preferred stock, shares authorized 3,000,000   3,000,000
Preferred stock, par value         
Common stock, shares authorized 5,000,000 5,000,000 5,000,000
Common stock, par value   $ 0.5   
Common stock, shares issued 2,703,840 1,750,003 987,524
Common stock, shares outstanding 2,703,840 1,716,316 2,703,840
Bargain purchase price gain $ 629,000    
Pre-tax expenses associated with consolidation 1,611,000    
Net income 1,910,000 1,636,000  
Riverview Bank [Member]
     
Business Acquisition [Line Items]      
Common stock, shares issued 987,524    
Common stock exchange ratio     1.00
Union Bank [Member]
     
Business Acquisition [Line Items]      
Common stock, shares outstanding 506,513    
Common stock exchange ratio 1.95   1.95
Net income $ 448,000