Note 18 - Related Party Transactions - Changes for Services (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Total Services from CONSOL Energy	$ 2,776	$ 2,740	$ 9,142	$ 9,300
Operating and Other Costs [Member]
Total Services from CONSOL Energy	1,006	838	2,715	2,368
Selling, General and Administrative Expenses [Member]
Total Services from CONSOL Energy	$ 1,770	$ 1,902	$ 6,427	$ 6,932