Note 4 - Stock Options and Other Stock Plans - Stock Option Assumption (Details) - Share-based Payment Arrangement, Option [Member] - $ / shares |
12 Months Ended | ||
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Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
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| Risk-free interest rate | 0.40% | 1.50% | 2.50% |
| Dividend yield | 1.90% | 2.10% | 2.20% |
| Expected life (years) (Year) | 4 years 7 months 6 days | 4 years 10 months 24 days | 5 years 2 months 12 days |
| Volatility | 28.30% | 23.40% | 22.70% |
| Weighted-average grant-date fair value of options granted (in dollars per share) | $ 39.97 | $ 32.20 | $ 30.37 |
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- Definition 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Details
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