Note 17 - Segment Information - Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Loss Before Income Tax	$ (154,047)	$ (3,442)	$ (127,179)	$ (27,805)
Interest Expense, net	16,045	15,723	47,493	46,116
Loss (Gain) on Debt Extinguishment	132	(1,078)	(657)	(17,911)
Interest Income	(737)	(76)	(2,406)	(442)
Depreciation, Depletion and Amortization	55,977	54,959	168,073	156,057
Unrealized Loss on Commodity Derivative Instruments	147,306	0	167,743	0
Pension Settlement	0	0	22	0
Stock/Unit-Based Compensation	1,888	2,212	4,607	9,462
Adjusted EBITDA	$ 66,564	$ 68,298	$ 257,696	$ 165,477