| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K/A | 10-K |
| Net income | 176.8 | 95.9 | 86.8 | 82.3 | 72.4 | 62.3 | | 57.7 |
| Depreciation and amortization | 91.4 | 82.0 | 78.1 | 74.7 | 72.5 | 73.4 | 60.4 | 58.1 |
| Stock-based compensation | 6.9 | 6.3 | 6.0 | 4.4 | 3.6 | 3.2 | | 1.8 |
| Deferred taxes | 28.9 | 15.2 | 12.0 | 19.2 | 24.0 | 19.1 | 26.0 | 28.2 |
| Change in working capital [+] | -58.2 | 11.3 | -7.9 | -31.8 | -9.4 | 2.4 | 0.0 | -26.9 |
| Accounts receivable | -61.0 | -6.3 | -1.9 | -8.6 | -2.1 | -0.9 | -1.7 | -4.6 |
| Inventories | -54.3 | 5.7 | 8.4 | -18.2 | -4.3 | 1.9 | 2.0 | -12.6 |
| Other current assets | | | | | | | -0.2 | |
| Accounts payable | 38.7 | 3.8 | -5.1 | | | | | |
| Other | 18.4 | 8.1 | -9.4 | -5.0 | -3.0 | 1.5 | | -9.7 |
| Other operating activities | -14.5 | 1.3 | 10.0 | -5.4 | 10.4 | 2.9 | | 6.9 |
| Cash from operations | 231.2 | 211.9 | 185.0 | 143.4 | 173.6 | 163.4 | 131.5 | 125.8 |
| |
| Capital expenditures [+] | -171.8 | -371.6 | -207.4 | -105.4 | -132.9 | -161.3 | -160.1 | -163.6 |
| Purchases of property and equipment | -171.8 | -371.6 | -207.4 | -105.4 | -132.9 | -161.3 | -160.1 | -163.6 |
| Sales of property and equipment | 9.7 | 5.0 | 8.5 | 2.4 | 4.5 | 4.8 | | 2.5 |
| Acquisitions | | | | | | 1.5 | | |
| Other cash from investing | -9.4 | -9.1 | -10.6 | -4.4 | -4.2 | -4.4 | | -3.4 |
| Cash from investing | -171.5 | -375.7 | -209.5 | -107.4 | -132.6 | -159.3 | -156.0 | -164.5 |
| |
| Cash dividends paid | -64.9 | -60.3 | -55.7 | -53.2 | -50.6 | | | |
| Issuance of common stock, net | 0.7 | 52.4 | 20.3 | -3.0 | 2.6 | 44.3 | | 25.7 |
| Financing costs | | | | -0.8 | -0.4 | -0.9 | | -0.9 |
| Other cash from financing | 4.8 | 151.6 | 80.2 | 4.1 | 22.9 | -49.3 | | 24.3 |
| Cash from financing | -59.4 | 143.7 | 44.8 | -51.4 | -24.8 | -4.1 | 38.4 | 50.9 |
| |
| Free cash flow | 59.4 | -159.6 | -22.3 | 38.0 | 40.7 | 2.1 | -28.5 | -37.8 |
| Per share (diluted) | $1.42 | ($3.90) | ($0.56) | $0.95 | $1.02 | $0.05 | | ($1.03) |