Note 19 - Supplemental Oil and Gas Disclosures - Unaudited - Capitalized Costs Related to Oil and Natural Gas (Details) - USD ($) $ in Millions |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|---|
| Proved oil and natural gas properties and equipment | $ 8,567.5 | $ 8,532.2 | $ 8,169.9 |
| Accumulated depreciation, depletion and amortization related to oil, NGLs and natural gas activities | (7,890.9) | (7,793.3) | (7,665.1) |
| Net capitalized costs related to producing activities | $ 676.6 | $ 738.9 | $ 504.8 |
| X | ||||||||||
- Definition Amount of accumulated depreciation, depletion, amortization and valuation allowance relating to oil and gas producing activities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Capitalized costs of proved properties that include fee ownership or a lease, concession, or other interest representing the right to extract oil or gas subject to such terms as may be imposed by the conveyance of that interest. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Net amount of capitalized costs relating to oil and gas producing activities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|