Note 10 - Benefit Plans (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Other Assets [Member]
Cash Surrender Value of Life Insurance	$ 9.2	$ 7.7
Other Noncurrent Liabilities [Member]
Deferred Compensation Liability, Classified, Noncurrent	7.9	7.7
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(13.6)
Defined Benefit Plan, Expected Amortization, Next Fiscal Year	0.1
Postretirement Life Insurance [Member]
Cash Surrender Value of Life Insurance	4.5	3.9
Gain (Loss) on Investments	$ 0.6	(0.8)
401(K) Plan [Member}
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	25.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0.5	$ 0.6