Note 5 - Retirement Plans - Pension Plan Asset Allocation (Details) |
Dec. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Asset allocation percentage | 100.00% | 100.00% |
| Defined Benefit Plan, Equity Securities [Member] | ||
| Asset allocation percentage | 57.00% | 63.00% |
| Defined Benefit Plan, Equity Securities [Member] | Minimum [Member] | ||
| Target Allocation | 45.00% | |
| Defined Benefit Plan, Equity Securities [Member] | Maximum [Member] | ||
| Target Allocation | 55.00% | |
| Defined Benefit Plan, Debt Security [Member] | ||
| Asset allocation percentage | 42.00% | 34.00% |
| Defined Benefit Plan, Debt Security [Member] | Minimum [Member] | ||
| Target Allocation | 45.00% | |
| Defined Benefit Plan, Debt Security [Member] | Maximum [Member] | ||
| Target Allocation | 55.00% | |
| Defined Benefit Plan, Real Estate [Member] | ||
| Asset allocation percentage | 1.00% | 3.00% |
| Defined Benefit Plan, Real Estate [Member] | Minimum [Member] | ||
| Target Allocation | 0.00% | |
| Defined Benefit Plan, Real Estate [Member] | Maximum [Member] | ||
| Target Allocation | 2.00% |