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Stock Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares available for future grant (in shares) 4,130,264.000 5,992,621 6,439,532 6,517,310
Aggregate unamortized outstanding stock based compensation $ 18.8 $ 15.2 $ 16.0  
Aggregate intrinsic value exercised based on market price (usd per share) $ 19.26      
Shares withheld on net settlement (in shares) 203 2,703 203  
Stock options [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expiration period 10 years      
Stock options [Member] | Minimum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period 4 years      
Stock options [Member] | Maximum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period 5 years      
Performance Restricted Stock Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period 3 years      
Non-performance Restricted Stock Units (RSUs) [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Percentage of units vested 33.00%