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Share-Based Compensation - Schedule of Fair Value Options Granted and Assumptions (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Share-based Compensation    
Stock options granted, weighted average fair value (in dollars per share) $ 33.58 $ 53.81
Stock Options    
Share-based Compensation    
Stock options granted, fair value $ 0.5 $ 0.5
Stock options, expiration period (in years) 7 years  
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]    
Dividend yield 1.20% 0.70%
Expected volatility 31.90% 24.60%
Risk-fee interest rate 2.60% 2.60%
Expected life of options (in years) 5 years 8 months 12 days 5 years 8 months 12 days
Forfeiture rate 0.00% 0.00%
Stock Options | Minimum    
Share-based Compensation    
Stock options, vesting period (in years) 3 years  
Stock Options | Maximum    
Share-based Compensation    
Stock options, vesting period (in years) 4 years