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Share-based Compensation - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expenses $ 2.0 $ 1.6
Restricted Stock Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Maximum unrecognized cost for stock options $ 18.8  
Unrecognized compensation cost, weighted average period of recognition 2 years 3 months 11 days  
Time Based Awards    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Vesting period 3 years  
Awards with Performance Conditions | 2015 LTIP    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Vesting period 3 years  
Awards with Performance Conditions | 2016 LTIP    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Performance measurement period 1 year  
Requisite service period 2 years  
Awards with Performance Conditions | 2017 LTIP    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Vesting period 3 years  
Performance measurement period 1 year  
Requisite service period 2 years  
Performance adjustment percent 25.00%