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Stock-Based Compensation Expense - Additional Information (Detail)
12 Months Ended
Dec. 31, 2019
USD ($)
group
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
Dec. 31, 2017
USD ($)
$ / shares
Dec. 31, 2016
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of groups within the employee population | group 2      
Estimated forfeiture rate for unvested options for senior management 9.00%      
Estimated forfeiture rate for unvested options for all non-senior management 12.00%      
Increase in compensation expense due to revised estimated forfeiture rates $ 499,000 $ 1,283,000 $ 673,000  
Weighted-average grant-date fair values of stock options granted | $ / shares $ 18.62 $ 20.84 $ 15.59  
Total intrinsic values of stock options exercised $ 90,762,000 $ 52,629,000 $ 136,672,000  
Total fair values of stock options vested 38,974,000 31,106,000 21,519,000  
Total unrecognized compensation expense related to non-vested stock options $ 53,491,000      
Recognition period for unrecognized compensation expense 1 year 7 months 28 days      
Stock-based compensation expense $ 45,589,000 41,090,000 31,942,000  
Income tax benefit recognized related to stock-based compensation expense 7,756,000 $ 7,317,000 10,473,000  
Compensation expense capitalized $ 0   $ 0 $ 0
Employee Stock Option [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares available for grant under stock option plans | shares 17,300,802      
Vesting period for stock option plans      
Expiration period of stock option plan 10 years      
Minimum [Member] | Employee Stock Option [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for stock option plans 4 years      
Minimum [Member] | Performance Shares [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for stock option plans 3 years      
Maximum [Member] | Employee Stock Option [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for stock option plans 5 years      
Maximum [Member] | Performance Shares [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period for stock option plans 3 years