Stock-Based Compensation (Valuation Assumptions) (Details) - Stock Appreciation Rights (SARs) [Member]	6 Months Ended
Jun. 30, 2021 $ / shares
1/24/2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Year	2020
Grant Date	Jan. 24, 2020
Expected Life	4 years 9 months 18 days
Expected Volatility	78.14%
Expected Dividend Yield	0.00%
Risk Free Interest Rate	0.83%
Fair Value Per Award	$ 4.88
9/14/2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Year	2020
Grant Date	Sep. 14, 2020
Expected Life	5 years 2 months 12 days
Expected Volatility	76.23%
Expected Dividend Yield	0.00%
Risk Free Interest Rate	0.89%
Fair Value Per Award	$ 4.74
11/30/2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Year	2020
Grant Date	Nov. 30, 2020
Expected Life	5 years 4 months 24 days
Expected Volatility	75.69%
Expected Dividend Yield	0.00%
Risk Free Interest Rate	0.92%
Fair Value Per Award	$ 4.57
1/5/2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Year	2021
Grant Date	Jan. 05, 2021
Expected Life	5 years 6 months
Expected Volatility	75.48%
Expected Dividend Yield	0.00%
Risk Free Interest Rate	0.93%
Fair Value Per Award	$ 4.65

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Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Fair Value Per Award

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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