| In millions, except per share items | Sep-30-20 | Jun-30-20 | Mar-31-20 | Dec-31-19 | Sep-30-19 | Jun-30-19 | Mar-31-19 | Dec-31-18 |
| | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K |
| REVENUES | | | | | | | | |
| Revenues | 115.4 | 90.7 | 133.4 | 174.1 | 163.3 | 155.5 | 141.5 | 171.2 |
| Revenues growth | -29.3% | -41.7% | -5.7% | 1.7% | 25.5% | 50.1% | 28.4% | 64.5% |
| OPERATING EXPENSES | | | | | | | | |
| Lease operating | 11.5 | 9.9 | 12.0 | 13.7 | 12.0 | 10.1 | 7.5 | 6.3 |
| Transportation, gathering and compression | 52.0 | 51.4 | 54.1 | | 57.0 | 51.9 | 41.2 | |
| |
| Cost, Product and Service [Extensible List] | | | | | | | | |
| Production and ad valorem taxes | 3.7 | 1.6 | 4.9 | 3.6 | 1.7 | 4.0 | 2.8 | 2.9 |
| Brokered natural gas and marketing expense | 7.3 | 7.7 | 9.3 | 10.7 | 10.6 | 12.0 | 9.5 | 13.2 |
| Depreciation, depletion, amortization and accretion | 53.2 | 42.8 | 44.1 | 42.1 | 45.5 | 38.6 | 29.9 | 36.3 |
| Exploration | 11.8 | 9.1 | 13.3 | 10.3 | 16.6 | 15.2 | 16.8 | 13.3 |
| General and administrative | 12.1 | 11.6 | 9.9 | 13.9 | 14.6 | 13.6 | 28.9 | 11.0 |
| Rig termination and standby | 0.3 | | | | 1.2 | | | |
| Gain on sale of assets | -0.1 | -1.9 | 0.6 | 0.3 | -0.7 | 0.0 | 0.0 | 0.0 |
| Other expense | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Total operating expenses | 151.9 | 132.2 | 148.1 | | 158.4 | 145.4 | 136.6 | |
| OPERATING INCOME (LOSS) | -36.5 | -41.5 | -14.7 | 21.0 | 4.9 | 10.2 | 4.9 | 47.6 |
| Operating margin | -31.6% | -45.7% | -11.0% | 12.0% | 3.0% | 6.5% | 3.4% | 27.8% |
| |
| OTHER INCOME (EXPENSE) | | | | | | | | |
| Gain (loss) on derivative instruments | -40.5 | -10.9 | 40.1 | 8.0 | 15.8 | 29.7 | -4.9 | 2.9 |
| Interest expense, net | -14.4 | -14.9 | -14.8 | -14.9 | -15.2 | -15.1 | -13.8 | -14.0 |
| Other income | 0.0 | 0.0 | 0.0 | 0.0 | | 0.0 | | |
| Total other income (expense), net | -54.9 | -25.9 | 25.3 | -6.9 | 0.6 | 14.6 | -18.8 | -11.1 |
| INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES | -91.4 | -67.3 | 10.6 | 14.0 | 5.5 | 24.8 | -13.9 | 36.5 |
| |
| Income tax benefit (expense) | | | | | | | | |
| INCOME (LOSS) FROM CONTINUING OPERATIONS | -91.4 | -67.3 | 10.6 | 14.0 | 5.5 | 24.8 | -13.9 | 36.5 |
| Income (loss) from discontinued operations, net of income tax | -0.8 | -1.5 | -7.8 | 0.0 | -1.2 | 2.7 | -0.2 | 0.0 |
| NET INCOME (LOSS) | -92.2 | -68.9 | 2.8 | 14.1 | 4.3 | 27.5 | -14.1 | 36.5 |
| |
| EARNINGS (LOSS) PER SHARE OF COMMON STOCK | | | | | | | | |
| Basic: | | | | | | | | |
| Weighted average common stock outstanding | 36.0 | 35.9 | 35.8 | 33.2 | 35.7 | 35.7 | 25.6 | 20.0 |
| Income (loss) from continuing operations | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Income (loss) from discontinued operations | 0.0 | 0.0 | 0.0 | | 0.0 | 0.0 | 0.0 | |
| |
| Net income (loss) | ($2.56) | ($1.92) | $0.08 | $0.41 | $0.12 | $0.77 | ($0.55) | $1.83 |
| |
| Diluted: | | | | | | | | |
| Weighted average common stock outstanding | 36.0 | 35.9 | 107.5 | 99.9 | 107.1 | 107.3 | 25.6 | 60.2 |
| Income (loss) from continuing operations | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Income (loss) from discontinued operations | 0.0 | 0.0 | 0.0 | | 0.0 | 0.0 | 0.0 | |
| Net income (loss) | ($2.56) | ($1.92) | $0.08 | $0.40 | $0.12 | $0.77 | ($0.55) | $1.83 |