| In millions, except per share items | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 | Dec-31-10 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Revenues [+] | 252.8 | 178.8 | 207.9 | 472.3 | 568.1 | 700.2 | 785.6 | 709.0 |
| Net interest income | | | | | 2.5 | -0.4 | 4.9 | |
| Other income | 1.6 | 0.5 | 3.4 | 8.2 | 2.5 | -0.4 | 4.9 | 0.6 |
| Revenue growth | 41.4% | -14.0% | -56.0% | -16.9% | -18.9% | -10.9% | 10.8% | 18.5% |
| Cost of goods sold [+] | 41.3 | 40.9 | 58.4 | 95.7 | 137.5 | 179.3 | 150.0 | 121.1 |
| Lease costs | 24.2 | 27.9 | 42.8 | 60.3 | 70.2 | 72.7 | 56.6 | 52.0 |
| Direct taxes | 14.5 | 10.6 | 12.2 | | | | | |
| Natural gas midstream costs | 2.6 | 2.4 | 3.5 | 35.4 | 67.3 | 106.5 | 93.4 | 69.1 |
| Gross profit | 211.5 | 137.9 | 149.5 | 376.5 | 430.6 | 520.9 | 635.6 | 587.9 |
| Gross margin | 83.7% | 77.1% | 71.9% | 79.7% | 75.8% | 74.4% | 80.9% | 82.9% |
| Selling, general and administrative [+] | 42.5 | 42.2 | 53.9 | 53.4 | 64.9 | 68.7 | 66.8 | 57.8 |
| General and administrative | 42.5 | 42.2 | 53.9 | 53.4 | 64.9 | 68.7 | 66.8 | 57.8 |
| Other operating expenses [+] | 66.3 | 23.4 | 596.3 | 183.5 | 265.9 | 102.2 | 158.7 | 86.5 |
| Exploration expenses | 0.1 | 0.1 | 0.2 | 0.5 | 0.3 | 8.8 | 3.6 | 9.1 |
| EBITDA [+] | 102.8 | 72.4 | -500.7 | 139.7 | 99.8 | 350.1 | 410.1 | 443.6 |
| EBITDA growth | 42.0% | -114.5% | -458.5% | 40.0% | -71.5% | -14.6% | -7.6% | 19.3% |
| EBITDA margin | 40.7% | 40.5% | -240.9% | 29.6% | 17.6% | 50.0% | 52.2% | 62.6% |
| Depreciation and amortization | 160.0 | 171.6 | 205.3 | 235.8 | 279.8 | 326.8 | 288.4 | 260.7 |
| EBIT [+] | -57.2 | -99.2 | -706.0 | -96.1 | -180.0 | 23.2 | 121.7 | 182.9 |
| EBIT growth | -42.4% | -85.9% | 634.4% | -46.6% | -875.5% | -80.9% | -33.5% | 54.5% |
| EBIT margin | -22.6% | -55.5% | -339.6% | -20.4% | -31.7% | 3.3% | 15.5% | 25.8% |
| Non-recurring items | 8.7 | | | | | | | |
| Interest expense, net [+] | 56.4 | 59.1 | 64.7 | 68.3 | 86.9 | 95.4 | 58.2 | 43.9 |
| Interest expense | 57.7 | 59.4 | 65.3 | 69.6 | 88.5 | 95.5 | 58.6 | 44.3 |
| Interest income | 1.4 | 0.2 | 0.6 | 1.3 | 1.6 | 0.2 | 0.4 | 0.4 |
| Other income (expense), net [+] | -17.4 | -12.0 | 105.9 | 197.4 | -44.5 | 74.4 | -15.1 | -10.6 |
| Gain (loss) on debt retirement | -8.2 | 8.7 | 1.7 | | -21.5 | 1.6 | | |
| Pre-tax income | -139.6 | -170.4 | -664.9 | 33.0 | -311.4 | 2.2 | 48.4 | 128.5 |
| Income taxes | -1.4 | 0.0 | -177.1 | 17.9 | -118.6 | 1.6 | 17.7 | 48.0 |
| Tax rate | 1.0% | 0.0% | 26.6% | 54.3% | 38.1% | 73.8% | 36.5% | 37.3% |
| Net income | -138.2 | -170.4 | -487.8 | 15.1 | -192.7 | 0.6 | 30.7 | 80.5 |
| Net margin | -54.7% | -95.3% | -234.6% | 3.2% | -33.9% | 0.1% | 3.9% | 11.4% |
| |
| Basic EPS [+] | ($1.80) | ($3.08) | ($10.10) | $0.31 | ($4.06) | $0.01 | $0.66 | $1.78 |
| Growth | -41.5% | -69.5% | -3314.8% | -107.7% | -33004.9% | -98.1% | -62.9% | 58.6% |
| Diluted EPS [+] | ($1.80) | ($3.08) | ($10.10) | $0.31 | ($4.06) | $0.01 | $0.65 | $1.75 |
| Growth | -41.5% | -69.5% | -3343.2% | -107.7% | -33116.0% | -98.1% | -62.9% | 57.3% |
| |
| Shares outstanding (basic) [+] | 76.9 | 55.4 | 48.3 | 48.0 | 47.5 | 47.2 | 46.5 | 45.2 |
| Growth | 38.8% | 14.7% | 0.6% | 1.1% | 0.6% | 1.4% | 2.9% | 1.1% |
| Shares outstanding (diluted) [+] | 76.9 | 55.4 | 48.3 | 48.4 | 47.5 | 47.4 | 47.2 | 45.9 |
| Growth | 38.8% | 14.7% | -0.3% | 2.0% | 0.3% | 0.2% | 2.9% | 1.9% |
| |
| EBIT is a non-GAAP figure that excludes all non-recurring expenses: restructuring costs, asset impairments, IPR&D writeoffs, and other unusual charges. |