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Stock-Based Compensation - Details of Nonvested Restricted Stock Units Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]      
Granted (in dollars per share) $ 0.00 $ 0.00  
Granted (in dollars per share) $ 0.00 $ 0.00  
Weighted average grant-date fair value of shares vested $ 2,633 $ 4,602 $ 3,905
Restricted Stock Units (RSUs)      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Beginning Balance (in shares) 197,388    
Granted (in shares) 143,169    
Vested (in shares) (99,697)    
Canceled (in shares) (3,409)    
Accrued dividend equivalents (in shares) 3,123    
Ending Balance (in shares) 240,574 197,388  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]      
Beginning Balance (in dollars per share) $ 33.50    
Granted (in dollars per share) 36.02 $ 36.35 $ 27.53
Vested (in dollars per share) 32.05    
Canceled (in dollars per share) 34.46    
Accrued dividend equivalents (in dollars per share) 35.09    
Ending Balance (in dollars per share) 35.75 33.50  
Granted (in dollars per share) $ 36.02 $ 36.35 $ 27.53
Weighted average grant-date fair value of shares vested $ 3,195 $ 2,629 $ 1,185