Note 8 - Assets Held for Sale, Asset Sales and Asset Impairments - Summary of Impairment of Vessels (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Impairment and other expense	$ 714	$ 15,643	$ 74,109
Reactivation of asset held for sale	1	1	0
Vessel, Obsolete Inventory [Member]
Impairment and other expense	$ 1,214	$ 1,905	$ 2,959
Obsolete inventory	0	0	0
Vessel, Other [Member]
Other	0	0	0
Other, impairment	$ 0	$ 0	$ (4,027)
Vessels Held for Sale [Member]
Assets held for sale	0	8	47
Impairment and other expense	$ 0	$ 15,388	$ 75,177
Reactivation of asset held for sale	1	3	2
Reactivation of asset held for sale	$ 500	$ 1,650	$ (0)