Note 25 - Related Party Transactions - Changes for Services (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Total Services from CONSOL Energy	$ 13,424	$ 11,528
Operating and Other Costs [Member]
Total Services from CONSOL Energy	3,820	3,219
Selling, General and Administrative Expenses [Member]
Total Services from CONSOL Energy	$ 9,604	$ 8,309