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Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) - Narrative (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 USD ($) Bcfe well $ / bbl $ / MMBTU | Dec. 31, 2019 USD ($) Bcfe well $ / MMBTU $ / bbl | Dec. 31, 2018 USD ($) Bcfe Tcfe well $ / bbl $ / MMBTU
Reserve Quantities [Line Items] |  |  |
Interest capitalized | $ | $ 907 | $ 3,372 | $ 4,470
Capitalized general and administrative costs | $ | $ 25,000 | $ 30,100 | $ 37,700
Increase (decrease) in reserve during the period | 239.8 | 1.1 | 711.2
Decline in performance |  |  |
Reserve Quantities [Line Items] |  |  |
Proved developed and undeveloped reserve, revision of previous estimate | (1.7) | (733.8) |
Lower commodity prices |  |  |
Reserve Quantities [Line Items] |  |  |
Proved developed and undeveloped reserve, revision of previous estimate | (1,268.4) | (296.4) |
Utica Shale |  |  |
Reserve Quantities [Line Items] |  |  |
Increase (decrease) in reserve during the period | 150.6 | 793.5 | 556.3
Planned unit development | well | 14 | 72 | 75
Proved developed and undeveloped reserves, sale of mineral in place |  |  | 44.9
Utica Shale | Decline in performance |  |  |
Reserve Quantities [Line Items] |  |  |
Planned unit development | well | 48 | 9 |
Proved developed and undeveloped reserve, revision of previous estimate | (720.3) | (347.2) | 8.3
Proved developed, revision of previous estimate | 263.8 | 90.2 |
Utica Shale | Lower commodity prices |  |  |
Reserve Quantities [Line Items] |  |  |
Proved developed and undeveloped reserve, revision of previous estimate | Tcfe |  |  | (1.0)
Utica Shale | Exclusion of PUD locations |  |  |
Reserve Quantities [Line Items] |  |  |
Planned unit development | well |  |  | 127
Utica Shale | Improved performance |  |  |
Reserve Quantities [Line Items] |  |  |
Proved developed and undeveloped reserve, revision of previous estimate |  |  | 82.4
Utica Shale | Change in ownership interest |  |  |
Reserve Quantities [Line Items] |  |  |
Proved developed and undeveloped reserve, revision of previous estimate |  |  | 67.6
Utica Shale | Increase in pricing |  |  |
Reserve Quantities [Line Items] |  |  |
Proved developed and undeveloped reserve, revision of previous estimate |  |  | 27.9
SCOOP Properties |  |  |
Reserve Quantities [Line Items] |  |  |
Increase (decrease) in reserve during the period | 87.8 | 302.9 | 90.1
Planned unit development | well | 8 | 37 | 11
SCOOP Properties | Decline in performance |  |  |
Reserve Quantities [Line Items] |  |  |
Planned unit development | well | 31 | 22 |
SCOOP Properties | Exclusion of PUD locations |  |  |
Reserve Quantities [Line Items] |  |  |
Planned unit development | well |  |  | 12
SCOOP Properties | Rescheduled drilling |  |  |
Reserve Quantities [Line Items] |  |  |
Proved undeveloped reserves, postponement of drilling period |  |  | 5 years
Louisiana Field |  |  |
Reserve Quantities [Line Items] |  |  |
Increase (decrease) in reserve during the period |  |  | 3.0
Planned unit development | well |  |  | 13
Oil derivatives |  |  |
Reserve Quantities [Line Items] |  |  |
Price per unit (usd per barrel or MMbtu) | $ / bbl | 39.54 | 55.85 | 65.56
Natural gas, per MMbtu |  |  |
Reserve Quantities [Line Items] |  |  |
Price per unit (usd per barrel or MMbtu) | $ / MMBTU | 1.99 | 2.58 | 3.10
Natural gas liquids |  |  |
Reserve Quantities [Line Items] |  |  |
Price per unit (usd per barrel or MMbtu) | $ / bbl | 15.40 | 21.25 | 32.02
Oil and gas properties |  |  |
Reserve Quantities [Line Items] |  |  |
Interest capitalized | $ | $ 900 | $ 3,400 | $ 4,500
Investment in Grizzly Oil Sands ULC |  |  |
Reserve Quantities [Line Items] |  |  |
Equity investment, ownership interest | 24.50% |  |

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