Note 3 - Allowance for Credit Losses - Schedule for Allowance for Credit Losses on Financing Receivables (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Affiliate credit loss impairment expense (credit)	$ 0	$ 0	$ (1,000)	$ 53,581
Trade Accounts Receivable [Member]
Balance			1,516
Affiliate credit loss impairment expense (credit)			707
Write offs			(89)
Other			0
Balance	2,134		2,134
Due from Affiliate [Member]
Balance			71,800
Affiliate credit loss impairment expense (credit)			(1,000)
Write offs			0
Other			(162)
Balance	$ 70,638		$ 70,638