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Share-based Compensation - Schedule of Changes in Restricted Stock and Stock Units (Detail) - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Time-based Awards [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Non-vested at the beginning of the period (in shares) 379,138  
Granted (in shares) 186,515 203,618
Vested (in shares) (171,451)  
Cancelled (in shares) (35,283)  
Non-vested at the end of the period (in shares) 358,919 379,138
Non-vested at the beginning of period (in dollars per share) $ 32.15  
Granted (in dollars per share) 43.73  
Vested (in dollars per share) 31.86  
Cancelled (in dollars per share) 32.54  
Non-vested at the end of period (in dollars per share) $ 38.27 $ 32.15
Performance-based Awards [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Non-vested at the beginning of the period (in shares) 192,310  
Granted (in shares)   55,330
Non-vested at the end of the period (in shares) 192,310 192,310
Non-vested at the beginning of period (in dollars per share) $ 34.45  
Non-vested at the end of period (in dollars per share) $ 34.45 $ 34.45
Performance-based or Market-based Stock Units [Member]    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Non-vested at the beginning of the period (in shares) 55,330  
Granted (in shares) 96,245  
Non-vested at the end of the period (in shares) 151,575 55,330
Non-vested at the beginning of period (in dollars per share) $ 33.12  
Granted (in dollars per share) 49.53  
Non-vested at the end of period (in dollars per share) $ 43.54 $ 33.12