Note 5 - Investment in Unconsolidated Affiliates - Company Operations Due from Affiliates (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Less impairment of due from affiliate		$ 0	$ (400)	$ (52,981)
Sonatide Marine Ltd [Member]
Due from Sonatide at beginning of year		49,011	41,623	89,246
Revenue earned by the company through Sonatide		0	41,775	44,254
Less amounts received from Sonatide		0	(26,429)	(36,160)
Less amounts used to offset Due to Sonatide obligations (A)	[1]	0	(8,530)	(11,848)
Less impairment of due from affiliate		0	(400)	(40,900)
Write off of due from affiliate in connection with the acquisition		(49,011)	0	0
Other		0	972	(2,969)
Due from Affiliates		$ 0	$ 49,011	$ 41,623

[1] We reduced the respective due from affiliates and due to affiliates balances each period through netting transactions based on agreement with the joint venture.