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Stock-Based Compensation - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Stock-based compensation $ 20,954,000 $ 20,185,000
Total unrecognized stock-based compensation expense $ 227,900,000  
Unrecognized compensation expense recognition period 2 years 10 months 24 days  
Recognized excess tax benefits (deficiencies) from stock-based compensation $ 0 (2,500,000)
Stock-based compensation capitalized as website and software development cost $ 4,600,000 4,800,000
Options, Granted 16,841  
Aggregate intrinsic value of awards exercised $ 1,400,000 2,000,000.0
Stock Options    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Stock-based compensation $ 2,100,000 3,200,000
Unrecognized compensation expense recognition period 1 year 9 months 18 days  
Unrecognized stock-based compensation expense $ 11,000,000.0  
Restricted Stock Units    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Stock-based compensation $ 18,900,000 17,000,000.0
Unrecognized compensation expense recognition period 2 years 10 months 24 days  
Fair value of awards vested during the period $ 25,600,000 $ 22,500,000
Unrecognized compensation expense related to share based awards other than options $ 216,900,000  
Non-vested restricted stock units or awards expected to vest 3,580,526  
Weighted average grant date fair value $ 65.44  
2015 Long-Term Incentive Plan    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Options, Granted 16,841 224,509