| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -39.4 | -3.9 | -88.2 | -8.0 | -145.4 | -31.5 | 46.7 | 80.8 |
| Depreciation and amortization [+] | | | | 0.6 | 3.8 | 4.8 | 4.8 | 3.6 |
| Amortization of intangible assets | | | | 0.6 | 3.8 | 4.8 | 4.8 | 3.6 |
| Asset impairment charges | | | | | 141.3 | 1.2 | 1.3 | 1.6 |
| Stock-based compensation | 0.7 | 0.9 | 0.7 | 0.7 | 0.9 | 2.5 | 2.1 | 1.6 |
| Tax benefit from stock-based compensation | | | | | -0.2 | -0.4 | | |
| Deferred taxes | | | | | 4.3 | 20.1 | | -24.4 |
| Change in working capital [+] | -6.8 | -4.3 | 3.1 | -11.1 | 28.7 | -92.5 | -4.1 | -36.8 |
| Restricted cash | | | | | | | -2.5 | -1.1 |
| Other | -6.8 | -4.3 | 3.1 | -11.1 | 28.7 | -92.5 | -1.6 | -35.7 |
| Other operating activities | 295.1 | -97.2 | 718.2 | -359.7 | 167.5 | -42.2 | 14.7 | 4.3 |
| Cash from operations | 249.6 | -104.5 | 633.9 | -377.5 | 201.0 | -138.0 | 65.5 | 30.7 |
| |
| Capital expenditures [+] | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Sales of property and equipment | 0.1 | -0.3 | -0.4 | -0.9 | -0.9 | -0.5 | -0.3 | 0.1 |
| Acquisitions | | | | | | | | -7.5 |
| Sales of short-term investments | | | | | | | 0.0 | 0.1 |
| Sales of short-term investments | | | | | | | 0.0 | 0.1 |
| Other cash from investing | 110.3 | 600.3 | 460.7 | 590.6 | 728.6 | 678.0 | 642.1 | 721.7 |
| Cash from investing | 110.4 | 600.0 | 460.3 | 589.7 | 727.7 | 677.5 | 641.9 | 714.4 |
| |
| Issuance of common stock, net | | | | | | 55.5 | 47.5 | |
| Option exercises | 0.0 | 0.0 | 0.0 | 0.3 | 0.5 | 0.6 | 0.2 | 1.0 |
| Financing costs | | | | | | -0.1 | -0.1 | -0.5 |
| Other cash from financing | -365.2 | -520.0 | -1,071.4 | -204.9 | -937.2 | -601.4 | -747.1 | -722.2 |
| Cash from financing | -365.2 | -520.0 | -1,071.5 | -205.2 | -937.6 | -546.5 | -699.7 | -722.7 |
| |
| Free cash flow | 249.6 | -104.5 | 633.9 | -377.5 | 201.0 | -138.0 | 65.5 | 30.7 |
| Per share (diluted) | $10.43 | ($4.90) | $29.83 | ($17.82) | $9.56 | ($7.10) | $4.41 | $2.35 |
| |
| Cash paid for interest | 11.9 | 25.7 | 50.6 | 116.8 | 123.7 | 93.8 | 77.5 | 63.3 |