Note 10 - Benefit Plans - Target Allocation (Details)	Dec. 31, 2021
Minimum [Member] | Fixed Income Securities [Member]
Target Allocation	80.00%
Minimum [Member] | Defined Benefit Plan, Equity Securities, US [Member]
Target Allocation	10.00%
Minimum [Member] | Defined Benefit Plan, Equity Securities, Non-US [Member]
Target Allocation	0.00%
Minimum [Member] | Defined Benefit Plan, Real Estate [Member]
Target Allocation	0.00%
Maximum [Member] | Fixed Income Securities [Member]
Target Allocation	100.00%
Maximum [Member] | Defined Benefit Plan, Equity Securities, US [Member]
Target Allocation	30.00%
Maximum [Member] | Defined Benefit Plan, Equity Securities, Non-US [Member]
Target Allocation	20.00%
Maximum [Member] | Defined Benefit Plan, Real Estate [Member]
Target Allocation	10.00%