| In millions, except per share items | Dec-31-17 | Dec-31-16 | Dec-31-15 | Sep-24-14 | Sep-25-13 | Sep-26-12 | Sep-28-11 | Sep-29-10 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 50.1 | 99.5 | -15.8 | 28.8 | 140.3 | 21.6 | 34.0 | 29.4 |
| Depreciation and amortization | 21.4 | 22.9 | 24.8 | 24.9 | 25.3 | 26.4 | 28.4 | 29.3 |
| Stock-based compensation | | | | | | | 1.0 | 1.7 |
| Deferred taxes | -64.3 | 38.5 | -26.5 | 9.2 | 72.0 | -2.7 | -2.2 | 0.2 |
| Change in working capital [+] | 13.5 | 9.1 | 5.9 | -2.6 | 5.5 | 4.9 | 24.2 | 22.7 |
| Other current assets | -2.2 | 4.3 | 0.7 | -5.9 | 0.2 | -3.7 | 2.1 | 4.0 |
| Other | 15.8 | 4.8 | 5.2 | 3.4 | 5.3 | 8.5 | 22.2 | 18.7 |
| Other operating activities | 5.0 | -106.6 | 64.2 | -32.7 | -204.2 | -0.2 | -10.6 | -14.7 |
| Cash from operations | 25.8 | 63.3 | 52.5 | 27.6 | 38.8 | 50.0 | 74.8 | 68.6 |
| |
| Capital expenditures [+] | -8.0 | -12.0 | -11.1 | -35.8 | -14.2 | -8.7 | -13.0 | -8.7 |
| Purchases of property and equipment | -8.0 | -12.0 | -11.1 | -35.8 | -14.2 | -8.7 | -13.0 | -8.7 |
| Sales of property and equipment | 1.0 | 1.1 | 0.1 | 2.6 | 2.4 | 2.4 | 2.0 | 1.9 |
| Acquisitions | | | | -40.1 | | | | |
| Sales of short-term investments | 41.8 | 32.1 | 12.4 | 12.0 | 0.0 | 38.1 | 90.1 | 47.1 |
| Sales of short-term investments | 41.8 | 32.1 | 12.4 | 12.0 | 0.0 | 38.1 | 90.1 | 47.1 |
| Other cash from investing | -46.4 | -49.9 | -114.8 | -109.4 | -49.0 | -119.7 | -168.6 | -71.8 |
| Cash from investing | -11.5 | -28.8 | -113.3 | -170.8 | -60.8 | -87.9 | -89.5 | -31.4 |
| |
| Cash dividends paid | 9.4 | 26.3 | 19.8 | 10.3 | | | | |
| Option exercises | 0.0 | 0.1 | 0.2 | 0.0 | 0.0 | 0.4 | 0.0 | 0.3 |
| Other cash from financing | -32.4 | -41.4 | -31.9 | 162.5 | 56.4 | -0.3 | 66.2 | -40.7 |
| Cash from financing | -23.0 | -15.2 | -12.3 | 172.9 | 56.3 | -0.7 | 66.2 | -41.0 |
| |
| Free cash flow | 17.7 | 51.3 | 41.4 | -8.2 | 24.6 | 41.3 | 61.7 | 60.0 |
| Per share (diluted) | $14.45 | $41.94 | $26.62 | ($4.81) | $15.92 | $26.55 | $42.86 | $42.67 |