Note 2 - Business Segments and Sales of Products (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Environmental Services [Member]
Revenues	$ 65,000		$ 65,000
Financially-settled Forward Contracts [Member]
Derivative, Gain (Loss) on Derivative, Net, Total	$ 1,600,000	$ 5,000,000	$ 8,100,000	$ 4,500,000