Stock Options And Restricted Stock Awards (Weighted-Average Estimated Fair Value of Employee Stock Options Granted) (Details) - Stock Options [Member] - $ / shares |
12 Months Ended | |
---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Weighted average fair value | $ 29.78 | $ 14.72 |
Risk-free discount rate, minimum | 1.72% | 2.32% |
Risk-free discount rate, maximum | 2.29% | 2.84% |
Volatility | 43.00% | 45.00% |
Minimum [Member] | ||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Expected life | 4 years 2 months 12 days | 4 years 1 month 6 days |
Maximum [Member] | ||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Expected life | 4 years 4 months 24 days | 4 years 2 months 12 days |