| 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 | 41.4 | 33.2 | 16.1 | 14.5 | 11.6 | 37.2 | 19.6 | 20.9 |
| Depreciation and amortization [+] | 21.1 | 21.8 | 20.7 | 19.0 | 18.6 | 16.0 | 15.4 | 13.8 |
| Depreciation | 19.8 | 20.5 | 19.4 | 17.8 | 17.4 | 16.0 | 15.4 | 13.8 |
| Amortization of intangible assets | 1.3 | 1.3 | 1.3 | 1.2 | 1.2 | | | |
| Asset impairment charges | | | | | | | 0.1 | |
| Stock-based compensation | 6.0 | 5.5 | 3.4 | 2.2 | 6.6 | 3.2 | 3.2 | 4.4 |
| Deferred taxes | 3.0 | -0.7 | 4.6 | 10.1 | 3.8 | -11.7 | 4.9 | 3.0 |
| Change in working capital [+] | -14.2 | -5.7 | 11.7 | -8.8 | -0.2 | -6.7 | -1.4 | 3.8 |
| Accounts receivable | -5.4 | -4.1 | -4.3 | -5.8 | -5.1 | -4.3 | -5.2 | -2.3 |
| Inventories | 2.3 | -4.4 | 3.5 | -2.8 | -0.2 | 1.4 | 2.0 | 2.6 |
| Other current assets | -1.9 | -1.2 | -1.0 | -0.9 | -1.0 | 0.1 | -1.2 | 0.2 |
| Other | -9.2 | 4.0 | 13.5 | 0.7 | 6.1 | -4.0 | 2.9 | 3.4 |
| Other operating activities | 3.8 | 30.2 | 26.5 | 6.2 | 8.5 | 7.2 | 8.2 | 5.6 |
| Cash from operations | 61.0 | 84.2 | 82.9 | 43.2 | 49.0 | 45.2 | 50.0 | 51.5 |
| |
| Capital expenditures [+] | -26.1 | -24.9 | -15.2 | -15.4 | -13.5 | -16.4 | -16.8 | -29.7 |
| Purchases of property and equipment | -26.1 | -24.9 | -15.2 | -15.4 | -13.5 | -16.4 | -16.8 | -29.7 |
| Sales of property and equipment | 5.0 | 7.9 | 8.5 | 1.0 | | 5.7 | 4.4 | 0.1 |
| Acquisitions | -33.9 | -3.3 | -28.0 | -140.9 | -38.0 | -28.8 | -26.6 | -9.7 |
| Other cash from investing | 2.4 | 7.8 | 0.2 | -3.6 | | | -6.3 | -6.1 |
| Cash from investing | -52.5 | -12.5 | -34.4 | -158.9 | -51.5 | -39.5 | -45.3 | -45.5 |
| |
| Cash dividends paid | -6.8 | -7.3 | -6.0 | -5.4 | -5.5 | -3.7 | -2.5 | -1.8 |
| Repurchase of common stock, net | -36.7 | -140.0 | | -9.2 | -16.3 | -16.4 | | -45.0 |
| Option exercises | 1.7 | 2.6 | 1.2 | 1.4 | 1.2 | 1.5 | 0.9 | 0.8 |
| Financing costs | | | | | -1.4 | | -0.7 | 0.0 |
| Other cash from financing | 36.7 | 78.5 | -41.0 | 131.7 | 23.9 | 13.5 | 0.6 | 41.7 |
| Cash from financing | -8.5 | -71.5 | -48.3 | 115.7 | 2.2 | -8.1 | -2.0 | -5.9 |
| |
| Free cash flow | 34.9 | 59.4 | 67.7 | 27.8 | 35.5 | 28.8 | 33.2 | 21.7 |
| Per share (diluted) | $2.22 | $3.25 | $3.75 | $1.55 | $1.93 | $1.63 | $1.90 | $1.19 |