v3.24.3
Stock-based compensation - Stock Options Outstanding and Activity During the Period (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 9 Months Ended 12 Months Ended
Sep. 30, 2024
Dec. 31, 2023
Options Outstanding    
Beginning Balance (in shares) 1.1  
Granted (in shares) 0.1  
Exercised (in shares) (0.2)  
Canceled/Forfeited (in shares) (0.0)  
Ending Balance (in shares) 1.0 1.1
Vested and expected to vest (in shares) 1.0  
Exercisable (in shares) 0.8  
Weighted-Average Exercise Price    
Beginning Balance (in usd per share) $ 41.38  
Granted (in usd per share) 85.18  
Exercised (in usd per share) 34.46  
Canceled/Forfeited (in usd per share) 61.58  
Ending Balance (in usd per share) 46.92 $ 41.38
Vested and expected to vest (in usd per share) 46.54  
Exercisable (in usd per share) $ 39.30  
Weighted-Average Remaining Contractual Term (Years)    
Balance 5 years 7 months 6 days 5 years 9 months 18 days
Vested and expected to vest 5 years 7 months 6 days  
Exercisable 4 years 9 months 18 days  
Aggregate Intrinsic Value    
Balance $ 40.3 $ 51.3
Vested and expected to vest 40.2  
Exercisable $ 37.1