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Stock-Based Compensation - Summary of Stock Based Compensation Activity (Detail) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Restricted Shares [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Stock based compensation, Shares Outstanding, beginning balance 5,067 5,067 7,900
Stock based compensation, Shares, Vested (2,034)    
Stock based compensation, Shares, Forfeited (633)   (2,833)
Stock based compensation, Shares Outstanding, ending balance 2,400 5,067 5,067
Stock based compensation, Weighted Average Fair Value Per Share, beginning balance $ 23.13 $ 23.13 $ 23.13
Stock based compensation, Weighted Average Fair Value Per Share, Vested 22.80    
Stock based compensation, Weighted Average Fair Value Per Share, Forfeited 22.80 23.13 23.13
Stock based compensation, Weighted Average Fair Value Per Share, ending balance $ 23.42 $ 23.13 $ 23.13
Three Year Vest Non-Vested Restricted Stock [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Stock based compensation, Shares Outstanding, beginning balance 14,200    
Stock based compensation, Shares, Granted 19,700 14,500  
Stock based compensation, Shares, Vested (4,734)    
Stock based compensation, Shares, Forfeited (2,266) (300)  
Stock based compensation, Shares Outstanding, ending balance 26,900 14,200  
Stock based compensation, Weighted Average Fair Value Per Share, beginning balance $ 36.08    
Stock based compensation, Weighted Average Fair Value Per Share, Granted 55.93 $ 36.08  
Stock based compensation, Weighted Average Fair Value Per Share, Vested 36.08    
Stock based compensation, Weighted Average Fair Value Per Share, Forfeited 46.59 36.08  
Stock based compensation, Weighted Average Fair Value Per Share, ending balance $ 49.73 $ 36.08