| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 |
| | 8-K | 10-K | 10-K | 10-K | 10-K/A | 10-K |
| Net income | 74.1 | 31.6 | -0.4 | -36.8 | 10.8 | 8.3 |
| Depreciation and amortization [+] | 29.3 | 24.6 | 21.0 | 26.4 | 20.8 | 16.8 |
| Depreciation | 29.3 | 24.6 | 21.0 | 26.4 | 20.8 | 16.8 |
| Stock-based compensation | | 6.4 | 5.5 | 2.2 | 0.5 | 0.8 |
| Deferred taxes | | 6.1 | -16.8 | 4.1 | 4.3 | 1.5 |
| Change in working capital [+] | | 5.1 | -15.8 | -5.7 | -4.6 | -1.3 |
| Other current assets | | -5.0 | -2.9 | -3.5 | -0.5 | -3.8 |
| Other | | 10.1 | -12.9 | -2.2 | -4.1 | 2.6 |
| Other operating activities | 4.6 | 36.9 | 2.8 | 55.3 | 12.6 | 7.0 |
| Cash from operations | 108.0 | 110.8 | -3.7 | 45.6 | 44.3 | 33.1 |
| |
| Capital expenditures [+] | 0.0 | -29.8 | -25.8 | -20.8 | -23.2 | -23.6 |
| Purchases of property and equipment | | -29.8 | -25.8 | -20.8 | -23.2 | -23.6 |
| Sales of property and equipment | | 1.4 | 0.4 | 0.1 | 1.2 | 0.3 |
| Purchases of intangible assets | | | | | -0.1 | -2.4 |
| Acquisitions | | -6.2 | -35.8 | -100.9 | -51.4 | -45.1 |
| Purchases of short-term investments | | | | -30.0 | | |
| Purchases of short-term investments | | | | -30.0 | | |
| Other cash from investing | -189.3 | | -0.3 | | | |
| Cash from investing | -189.3 | -34.5 | -61.4 | -151.5 | -73.5 | -70.9 |
| |
| Issuance of common stock, net | | -9.0 | 90.4 | | -3.3 | 1.5 |
| Option exercises | | 1.7 | 0.8 | 3.6 | 0.4 | |
| Financing costs | | -0.4 | -0.7 | -9.4 | -0.5 | |
| Other cash from financing | 106.6 | -1.6 | -16.1 | 133.4 | 49.3 | 57.6 |
| Cash from financing | 106.6 | -11.9 | 74.2 | 139.1 | 46.1 | 59.1 |
| |
| Free cash flow | 108.0 | 81.0 | -29.5 | 24.8 | 21.1 | 9.5 |
| Per share (diluted) | $1.19 | $0.86 | ($0.35) | $0.40 | $0.34 | $0.16 |
| |
| Cash paid for interest | | 9.6 | 12.9 | 12.0 | 8.7 | 6.2 |
| Cash paid for income taxes | | 8.6 | | 1.8 | 1.6 | |