Note 11 - Retirement Plans - Allocation of Plan Assets (Details)	Dec. 31, 2022	Dec. 31, 2021
Plan assets, percent	100.00%	100.00%
Insurance General Account [Member]
Plan assets, percent	14.00%	13.00%
Cash and Cash Equivalents [Member]
Plan assets, percent	4.00%	2.00%
Equity Securities [Member]
Plan assets, percent	51.00%	50.00%
Fixed Income Securities [Member]
Plan assets, percent	28.00%	33.00%
Real Estate [Member]
Plan assets, percent	3.00%	2.00%