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Share-Based Compensation Plans (Schedule of Fair Value of Option Granted Estimated on Date of Grant Using Weighted Average Assumptions) (Details)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share Based Compensation [Abstract]      
Expected volatility 64.00% 64.00% 65.00%
Expected term in years 5 years 6 years 4 years
Risk-free interest rate 1.80% 2.80% 1.70%
Dividend yield 0.00% 0.00% 0.00%