Note 1 - Description of the Business and Summary of Significant Accounting Policies - Estimated Fair Value of Long-term Debt (Details) - USD ($) $ in Thousands |
Dec. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Long-term Debt, carrying amount | $ 615,743 | |
| Reported Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | ||
| Long-term Debt, carrying amount | 615,743 | $ 622,509 |
| Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | ||
| Long-term Debt, fair value | $ 613,706 | $ 602,485 |