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, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Vessels sold from active fleet		10	3
Gain on sale of vessels	$ 250	$ (2,901)	$ 7,591
Vessels sold from assets held for sale			53
Total vessels sold	12	9
Vessels Held for Sale [Member]
Gain on sale of vessels	$ 5	$ (6,209)	$ 6,384
Vessels sold from assets held for sale	12	9	53
Vessels, Active Fleet [Member]
Vessels sold from active fleet	2	10	3
Gain on sale of vessels	$ 553	$ 3,499	$ 1,217
Vessel [Member]
Gain on sale of vessels	$ 558	$ (2,710)	$ 7,601
Total vessels sold	14	19	56