Note 4 - Allowance for Credit Losses - Schedule for Allowance for Credit Losses on Financing Receivables (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Affiliate credit loss impairment credit	$ 0	$ (1,000)	$ 0	$ (1,000)
Trade Accounts Receivable [Member]
Balance			1,948
Affiliate credit loss impairment credit			340
Acquisition of Sonatide joint venture (see Note 8)			0
Other			0
Balance	2,288		2,288
Due from Affiliate [Member]
Balance			72,456
Affiliate credit loss impairment credit			0
Acquisition of Sonatide joint venture (see Note 8)			(59,678)
Other			(563)
Balance	$ 12,215		$ 12,215