Note 1 - Significant Accounting Policies (Tables)
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12 Months Ended |
Dec. 31, 2019 |
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| Notes Tables |
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| Schedules of Concentration of Risk, by Risk Factor [Table Text Block] |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Shell Trading (US) Co./ Shell Energy N.A. | | | 11 | % | | | 30 | % | | | 46 | % | | BP Products North America | | | 40 | % | | | 20 | % | | | ** | | | Vitol Inc. | | | 12 | % | | | 14 | % | | | 15 | % | |
| Accounts Receivable, Allowance for Credit Loss [Table Text Block] |
| | | | | | | | | | | | Allowance for doubtful accounts, beginning of period | | $ | 9,692 | | | $ | 9,114 | | | $ | 7,602 | | | Additional provisions for the year | | | 206 | | | | 1,233 | | | | 1,512 | | | Uncollectible accounts written off | | | — | | | | (655 | ) | | | — | | | Allowance for doubtful accounts, end of period | | $ | 9,898 | | | $ | 9,692 | | | $ | 9,114 | | |
| Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] |
| | | | | | | | | | | | | | Derivatives – current (1) | | $ | 7,266 | | | $ | 60,687 | | | Unamortized bonds/insurance premiums | | | 4,357 | | | | 5,197 | | | Prepaid deposits related to royalties | | | 7,980 | | | | 8,872 | | | Prepayment to vendors | | | 10,202 | | | | 864 | | | Other | | | 886 | | | | 786 | | | Prepaid expenses and other assets | | $ | 30,691 | | | $ | 76,406 | | |
| Property, Plant and Equipment [Table Text Block] |
| | | | | | | | | | | | | | Oil and natural gas properties and equipment | | $ | 8,532,196 | | | $ | 8,169,871 | | | Furniture, fixtures and other | | | 20,317 | | | | 20,228 | | | Total property and equipment | | | 8,552,513 | | | | 8,190,099 | | | Less accumulated depreciation, depletion and amortization | | | 7,803,715 | | | | 7,674,678 | | | Oil and natural gas properties and other, net | | $ | 748,798 | | | $ | 515,421 | | |
| Schedule of Other Assets, Noncurrent [Table Text Block] |
| | | | | | | | | | | | | | Appeal bond deposits | | $ | 6,925 | | | $ | 6,925 | | | Escrow deposit – Apache lawsuit (Note 18) | | | — | | | | 49,500 | | | Unamortized debt issuance costs | | | 3,798 | | | | 4,773 | | | Investment in White Cap, LLC | | | 2,590 | | | | 2,586 | | | Derivatives | | | 2,653 | | | | 21,275 | | | Unamortized brokerage fee for Monza | | | 3,423 | | | | 2,277 | | | Proportional consolidation of Monza's other assets (Note 4) | | | 5,308 | | | | 3,275 | | | ROU assets (Note 7) | | | 7,936 | | | | — | | | Other | | | 814 | | | | 936 | | | Total other assets | | $ | 33,447 | | | $ | 91,547 | | |
| Schedule of Accrued Liabilities [Table Text Block] |
| | | | | | | | | | | | | | Accrued interest | | $ | 10,180 | | | $ | 12,385 | | | Accrued salaries/payroll taxes/benefits | | | 2,377 | | | | 2,320 | | | Incentive compensation plans | | | 9,794 | | | | 10,817 | | | Litigation accruals | | | 3,673 | | | | 3,673 | | | Lease liability (Note 7) | | | 2,716 | | | | — | | | Derivatives | | | 1,785 | | | | — | | | Other | | | 371 | | | | 416 | | | Total accrued liabilities | | $ | 30,896 | | | $ | 29,611 | | |
| Other Noncurrent Liabilities [Table Text Block] |
| | | | | | | | | | | | | | Dispute related to royalty deductions | | $ | 4,687 | | | $ | 4,687 | | | Dispute related to royalty-in-kind | | | 250 | | | | 2,235 | | | Lease liability (Note 7) | | | 4,419 | | | | — | | | Apache lawsuit (Note 18) | | | — | | | | 49,500 | | | Uncertain tax positions including interest/penalties (Note 13) | | | — | | | | 11,523 | | | Other | | | 632 | | | | 745 | | | Total other liabilities (long-term) | | $ | 9,988 | | | $ | 68,690 | | |