| 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 | 176.3 | 49.6 | -60.4 | -50.4 | 3.9 | -66.4 | -47.2 | -92.8 |
| Depreciation and amortization | 42.7 | 48.0 | 54.7 | 54.4 | 57.6 | 58.4 | 59.8 | 69.6 |
| Asset impairment charges | | | 20.8 | | | 9.9 | | |
| Stock-based compensation | 4.3 | 3.4 | 2.5 | 1.4 | 1.1 | 1.5 | 2.0 | 2.3 |
| Deferred taxes | -23.4 | -14.2 | -3.0 | -2.3 | -2.3 | 0.8 | -0.7 | 24.4 |
| Change in working capital [+] | -23.8 | -78.9 | 47.6 | 53.6 | -96.3 | -47.5 | 12.0 | 49.5 |
| Accounts receivable | -27.2 | -74.7 | -15.2 | 56.8 | -36.1 | -38.5 | 4.0 | 0.5 |
| Inventories | -19.6 | -112.9 | 37.7 | 63.7 | -77.9 | -55.6 | 8.0 | 34.4 |
| Other current assets | 11.4 | -15.7 | 2.3 | 1.9 | -5.4 | 9.3 | -16.7 | 9.9 |
| Accounts payable | -7.8 | 121.2 | 11.9 | -53.2 | 29.4 | 37.6 | 21.0 | 1.4 |
| Other | 19.4 | 3.2 | 10.8 | -15.6 | -6.3 | -0.3 | -4.2 | 3.3 |
| Other operating activities | -15.5 | 2.8 | -4.9 | -11.3 | -0.2 | 41.9 | 17.5 | 10.9 |
| Cash from operations | 160.7 | 10.7 | 57.2 | 45.4 | -36.2 | -1.3 | 43.5 | 63.9 |
| |
| Capital expenditures | -47.0 | -38.8 | -21.7 | -36.4 | -39.0 | -32.6 | -41.9 | -48.4 |
| Purchases of property and equipment | -47.0 | -38.8 | -21.7 | -36.4 | -39.0 | -32.6 | -41.9 | -48.4 |
| Purchases of short-term investments | | | | | | 50.0 | -50.0 | |
| Purchases of short-term investments | | | | | | 50.0 | -50.0 | |
| Other cash from investing | 10.2 | 1.2 | 54.9 | -56.2 | 2.1 | 1.0 | 2.2 | -1.5 |
| Cash from investing | -36.8 | -37.6 | 33.2 | -92.6 | -36.9 | 18.4 | -89.7 | -49.9 |
| |
| Cash dividends paid | | | -0.6 | -1.2 | -1.2 | -1.2 | -1.1 | -1.1 |
| Repurchase of common stock, net | -25.0 | | | | | | | |
| Option exercises | | | | | | | | 0.1 |
| Other cash from financing | -36.3 | 13.9 | -38.0 | 33.3 | 18.7 | -22.9 | -5.3 | 0.5 |
| Cash from financing | -61.3 | 13.9 | -38.6 | 32.1 | 17.5 | -24.1 | -6.4 | -0.7 |
| |
| Free cash flow | 113.7 | -28.1 | 35.5 | 9.0 | -75.2 | -33.9 | 1.6 | 15.5 |
| Per share (diluted) | $1.79 | ($0.45) | $0.58 | $0.15 | ($1.25) | ($0.57) | $0.03 | $0.29 |
| |
| Cash paid for interest | 31.6 | 34.6 | 29.2 | 32.5 | 30.8 | 38.2 | 34.4 | 34.1 |
| Cash paid for income taxes | 24.1 | 16.3 | 12.4 | 10.4 | 12.4 | 4.6 | 5.5 | -0.2 |