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Stock-Based Compensation - Schedule of Stock Option Activity (Details) - $ / shares
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Stock Options      
Outstanding at period start (in shares) 2,677,449    
Granted (in shares) 43,770    
Exercised (in shares) (1,171,786) (770,597) (840,175)
Forfeited (in shares) (23,308)    
Outstanding at period end (in shares) 1,526,125 2,677,449  
Weighted- Average Exercise Price       
Stock options outstanding at period start (in dollars per share) $ 91.51    
Granted (in dollars per share) 213.54    
Exercised (in dollars per share) 86.12    
Forfeited (in dollars per share) 156.02    
Stock options outstanding at period end (in dollars per share) $ 98.17 $ 91.51