Note 7 - Affiliate Balances - Amounts Due From Affiliate (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Due from Sonatide at December 31, 2019				$ 125,972
Affiliate credit loss impairment expense		$ 0	$ 0	(53,581)	$ 0
Total due from Sonatide at September 30, 2020		65,692		65,692
Sonatide [Member]
Due from Sonatide at December 31, 2019				89,246
Revenue earned by the company through Sonatide				34,378
Less amounts received from Sonatide				(27,761)
Less amounts used to offset due to Sonatide obligations (A)	[1]			(8,145)
Affiliate credit loss impairment expense				(41,500)
Other				(591)
Total due from Sonatide at September 30, 2020		$ 45,627		$ 45,627

[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.