Note 11 - Properties and Equipment, Accrued Expenses, Other Current Liabilities, and Other Liabilities (Details Textual) $ in Thousands, € in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2025 USD ($)	Mar. 31, 2025 EUR (€)	Mar. 31, 2024 USD ($)	Dec. 31, 2024
Number of Vessels	214	214		211
Proceeds from Sale of Productive Assets	$ 3,816		$ 12,463
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property	$ 2,538		$ 11,039
Crew Boats [Member]
Number of Vessels	1	1
Down Payment To Start Construction On Crew Boats	$ 400	€ 0.4
Expected Cost of Boats	$ 1,700	€ 1.6
Vessel [Member]
Number of Vessels Sold	2	2	3
Proceeds from Sale of Productive Assets	$ 3,800		$ 12,500
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property	$ 2,500		$ 11,000