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Share-Based Compensation - Valuation Assumptions (Details) - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Equity [Abstract]      
Risk-free interest rate 2.49% 2.67% 1.84%
Expected life in years 5 years 10 months 24 days 6 years 5 years
Expected volatility 20.00% 20.00% 21.00%
Expected dividend yield 1.44% 1.43% 1.40%
Estimated fair value of options granted per share (in dollars per share) $ 15.45 $ 14.08 $ 10.50