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Note 13 - Long-term Debt and Credit Arrangements - Schedule of Long-term Debt (Details) (Parentheticals) - The 2.75% Convertible Notes [Member] | Sep. 30, 2021 | Dec. 31, 2020 | Sep. 30, 2020 | Nov. 30, 2019
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Interest rate | 2.75% | 2.75% | 2.75% | 2.75%
Convertible Debt [Member] |  |  |  |
Interest rate | 2.75% |  | 2.75% |

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