| 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 | 15.2 | 26.3 | 46.6 | 88.2 | 53.2 | 23.5 | 56.3 | 46.4 |
| Depreciation and amortization [+] | 10.5 | 10.5 | 11.2 | 12.1 | 11.2 | 11.6 | 10.8 | 10.2 |
| Depreciation | 10.5 | 10.5 | 11.2 | 12.1 | 11.2 | 11.6 | 10.8 | 10.2 |
| Asset impairment charges | | 1.3 | | | | 0.8 | 2.4 | 0.6 |
| Stock-based compensation | 0.0 | | 0.0 | 0.0 | 0.4 | 1.0 | 1.9 | 2.0 |
| Deferred taxes | -1.8 | -10.5 | -0.6 | -5.1 | -1.3 | -13.7 | -5.3 | -3.7 |
| Change in working capital [+] | 23.4 | 17.9 | 35.2 | -57.9 | 13.6 | 18.0 | 18.4 | -11.4 |
| Accounts receivable | 3.1 | -7.9 | 88.9 | -94.0 | 5.7 | 2.4 | 22.0 | 3.8 |
| Inventories | 0.2 | 7.0 | 3.7 | 1.7 | 4.5 | 8.3 | 12.9 | -19.6 |
| Accounts payable | 13.8 | 2.1 | -48.6 | 41.5 | 1.2 | -4.4 | -11.6 | 4.1 |
| Accrued expenses | -0.9 | 0.9 | 0.5 | 1.1 | 0.3 | 0.1 | -0.6 | -1.7 |
| Deferred revenues | | | | | | | | 0.7 |
| Other | 7.3 | 15.9 | -9.2 | -8.2 | 2.0 | 11.6 | -4.1 | 1.3 |
| Other operating activities | 5.1 | -1.4 | 4.1 | -2.6 | 8.5 | -2.0 | 6.4 | -4.5 |
| Cash from operations | 52.5 | 44.1 | 96.4 | 34.6 | 85.6 | 39.3 | 91.0 | 39.6 |
| |
| Capital expenditures [+] | -4.8 | -1.5 | -4.5 | -7.0 | -4.9 | -3.6 | -4.5 | -7.2 |
| Purchases of property and equipment | -4.8 | -1.5 | -4.5 | -7.0 | -4.9 | -3.6 | -4.5 | -7.2 |
| Sales of property and equipment | 0.1 | | 0.1 | 0.0 | 0.0 | 0.0 | | 0.0 |
| Purchases of intangible assets | | | | | | | | -1.4 |
| Sales of short-term investments, net [+] | 1.3 | 17.1 | 4.7 | 11.3 | 28.6 | -7.7 | -30.2 | 9.4 |
| Purchases of short-term investments | | -23.5 | -5.1 | -20.1 | -19.7 | -31.0 | -60.7 | -39.1 |
| Sales of short-term investments | 1.3 | 40.7 | 9.8 | 31.4 | 48.2 | 23.3 | 30.5 | 48.5 |
| Other cash from investing | -0.4 | -0.7 | 0.2 | -0.1 | 1.7 | -1.9 | -0.5 | 1.2 |
| Cash from investing | -3.8 | 15.0 | 0.5 | 4.2 | 25.4 | -13.2 | -35.2 | 2.0 |
| |
| Cash dividends paid | -10.5 | -119.9 | -141.7 | -10.5 | -10.5 | -110.7 | -10.5 | -10.5 |
| Issuance of common stock, net | | 0.2 | | | | | 0.2 | |
| Financing costs | | | -0.5 | | | | | -0.7 |
| Other cash from financing | | 0.0 | -0.8 | | -0.2 | -0.1 | -0.3 | -1.9 |
| Cash from financing | -10.5 | -119.7 | -142.1 | -10.5 | -10.7 | -110.8 | -10.5 | -11.7 |
| |
| Free cash flow | 47.7 | 42.6 | 91.9 | 27.7 | 80.7 | 35.8 | 86.5 | 32.4 |
| Per share (diluted) | $1.09 | $0.97 | $2.10 | $0.63 | $1.85 | $0.82 | $1.99 | $0.75 |
| |
| Cash paid for interest | 0.0 | 0.0 | 0.0 | | | | | |