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Stock-Based Compensation - Assumptions Used to Estimate Fair Value (Details) - Stock Options
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield 1.40% 1.70% 2.20%
Expected volatility 32.00% 45.00% 43.00%
Risk free interest rate 2.90% 2.20% 1.30%
Weighted average expected option life in years 5 years 10 months 25 days 7 years 6 months 5 years 9 months 18 days