Stock-Based Compensation (Fair Value Of Grant On Date Of Grant Using The Black-Scholes Options Pricing Model) (Details)	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Risk-free interest rate (in hundredths)	0.68%	2.63%
Expected dividend yield (in hundredths)
Expected volatility (in hundredths)	45.20%	41.83%
Minimum [Member]
Expected lives (years)	1 year	1 year
Maximum [Member]
Expected lives (years)	6 years 3 months 18 days	6 years 3 months 18 days

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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