Note 3 - Long-term Debt (Details Textual) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Line of Credit Facility, Maximum Borrowing Capacity	$ 30.0
Letters of Credit Outstanding, Amount	20.7	$ 20.7
Line of Credit Facility, Remaining Borrowing Capacity	$ 9.3
Line of Credit Facility, Dividends Payment, Maximum		$ 150.0
Credit Facility [Member]
Long-Term Debt, Weighted Average Interest Rate, at Point in Time	8.50%