Note 8 - Assets Held for Sale, Asset Sales and Asset Impairments - Summary of Vessel Sales and Gains on Sales of Vessels (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Vessels sold from active fleet			10
Gain on sale of vessels	$ 8,701	$ 250	$ (2,901)
Total vessels sold/recycled	7	12	9
Vessels Held for Sale [Member]
Gain on sale of vessels	$ 3,088	$ 5	$ (6,209)
Vessels sold/recycled from assets held for sale	8	12	9
Vessels, Active Fleet [Member]
Vessels sold from active fleet	7	2	10
Gain on sale of vessels	$ 5,613	$ 553	$ 3,499
Vessel [Member]
Gain on sale of vessels	$ 8,701	$ 558	$ (2,710)
Total vessels sold/recycled	15	14	19