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Stock-Based Compensation (Details 2) - Stock Options [Member]
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
Expected life 7 years 7 years 7 years
Expected volatility 32.08% 34.63% 43.22%
Risk-free interest rate 2.50% 2.04% 1.65%