Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]      
Reserve $ 2,436,000 $ 15,322,000  
Federal fund sold period 1 day    
Mortgage loans maturity date 60 days    
Interest rate lock commitment derivatives 98,000 79,000  
Income recognized $ 18,000 $ 79,000  
Anti-dilutive potential common shares are excluded from the diluted earnings per share computation   30,000 30,000
Minimum [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Estimated useful life of Intangible assets 3 years    
Maximum [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Estimated useful life of Intangible assets 10 years