Summary of Significant Accounting Policies - Components of Accumulated Other Comprehensive Income, Included in Stockholders' Equity (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]      
Net unrealized gain on securities available for sale $ 7,416 $ 9,063  
Comprehensive income 14,618 13,356 7,917
Tax effect (2,969) (3,615)  
Net-of-tax amount 4,447 5,448  
Accumulated other comprehensive income 4,104 4,915  
Supplemental Director Retirement Plan [Member]
     
Schedule of Available-for-sale Securities [Line Items]      
Unrecognized net actuarial loss (104) (302)  
Unrecognized prior service cost (62) (90)  
Comprehensive income (166) (392)  
Tax effect 58 137  
Net-of-tax amount (108) (255)  
Long-Term Health Care Plan [Member]
     
Schedule of Available-for-sale Securities [Line Items]      
Unrecognized net actuarial loss (112) (161)  
Unrecognized prior service cost (249) (266)  
Comprehensive income (361) (427)  
Tax effect 126 149  
Net-of-tax amount $ (235) $ (278)