Note 1 - Basis of Presentation (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block]

	March 31, 2021		December 31, 2020
Derivatives - current (1)	$	2,701	$	2,752
Unamortized insurance/bond premiums		5,163		4,717
Prepaid deposits related to royalties		4,536		4,473
Prepayment to vendors		1,966		1,429
Other		984		461
Prepaid expenses and other assets	$	15,350	$	13,832

Property, Plant and Equipment [Table Text Block]

	March 31, 2021		December 31, 2020
Oil and natural gas properties and equipment, at cost	$	8,570,371	$	8,567,509
Furniture, fixtures and other		20,845		20,847
Total property and equipment		8,591,216		8,588,356
Less: Accumulated depreciation, depletion, amortization and impairment		7,922,247		7,901,478
Oil and natural gas properties and other, net	$	668,969	$	686,878

Schedule of Other Assets, Noncurrent [Table Text Block]

	March 31, 2021		December 31, 2020
Right-of-Use assets	$	11,218	$	11,509
Unamortized debt issuance costs		1,591		2,094
Investment in White Cap, LLC		2,872		2,699
Unamortized brokerage fee for Monza		—		626
Proportional consolidation of Monza's other assets (Note 4)		4,073		1,782
Derivatives		1,731		2,762
Other		1,128		998
Total other assets (long-term)	$	22,613	$	22,470

Schedule of Accrued Liabilities [Table Text Block]

	March 31, 2021		December 31, 2020
Accrued interest	$	25,420	$	10,389
Accrued salaries/payroll taxes/benefits		3,902		4,009
Litigation accruals		530		436
Lease liability		484		394
Derivatives		32,703		13,620
Other		1,381		1,032
Total accrued liabilities	$	64,420	$	29,880

Other Noncurrent Liabilities [Table Text Block]

	March 31, 2021		December 31, 2020
Dispute related to royalty deductions	$	5,247	$	5,467
Derivatives		3,514		4,384
Lease liability		11,257		11,360
Black Elk escrow		11,103		11,103
Other		659		624
Total other liabilities (long-term)	$	31,780	$	32,938