Note 5 - Investment in Unconsolidated Affiliates - Company Operations Due to Affiliates (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Due to Sonatide at beginning of year		$ 40,432	$ 32,767	$ 31,475
Plus commissions payable to Sonatide		0	3,832	4,152
Plus amounts paid by Sonatide on behalf of the company		0	10,914	9,037
Less amounts used to offset Due from Sonatide obligations (A)	[1]	0	(8,530)	(11,848)
Write off of due to affiliate in connection with the acquisition		(40,432)	0	0
Other		0	1,449	(49)
Due to Affiliate		$ 0	$ 40,432	$ 32,767

[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.