Note 12 - Long-term Debt - Long-term Debt (Details) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Apr. 30, 2021	Nov. 30, 2017
Unamortized discount	$ 7,751	$ 9,111
MEDCO Revenue Bonds in Series Due September 2025 at 5.75% [Member]
Debt Instrument, Interest Rate, Stated Percentage	5.75%	5.75%
PEDFA Solid Waste Disposal Revenue Bonds [Member]
Debt Instrument, Interest Rate, Stated Percentage	9.00%	9.00%	9.00%
Term Loan A Facility [Member]
Debt, Weighted Average Interest Rate	5.00%	5.25%
Advance Royalty Commitments [Member]
Debt, Weighted Average Interest Rate	8.01%	8.01%
Loans Payable [Member] | Term Loan B Facility [Member]
Principal Amount	$ 238,590	$ 239,277
Unamortized discount	$ 567	$ 687
Debt, Weighted Average Interest Rate	4.96%	4.61%
Senior Notes [Member] | Senior Secured Second Lien Notes due 2025 [Member]
Debt Instrument, Interest Rate, Stated Percentage	11.00%	11.00%		11.00%