| 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 | 46.0 | 45.1 | 33.1 | 25.8 | 16.3 | 11.8 | 12.1 | 11.4 |
| Depreciation and amortization | 14.1 | 14.5 | 12.1 | 10.6 | 8.6 | 6.7 | 6.6 | 4.7 |
| Stock-based compensation | | | | 5.8 | 4.1 | 2.6 | 1.1 | 1.6 |
| Deferred taxes | | | | -1.1 | -0.4 | 2.5 | -1.3 | 0.8 |
| Change in working capital [+] | -5.5 | 6.6 | 16.5 | -29.6 | 4.3 | 19.1 | -29.6 | -19.2 |
| Accounts receivable | | | | -37.5 | -0.7 | 19.4 | -33.6 | -19.5 |
| Other current assets | | | | -0.8 | 1.7 | -2.5 | -0.3 | 2.3 |
| Accounts payable | | | | 4.6 | 4.2 | 1.1 | -0.8 | 0.6 |
| Accrued expenses | -4.6 | -1.3 | 11.3 | -4.1 | -0.9 | 1.8 | | -2.6 |
| Other | -0.9 | 7.9 | 5.2 | 8.1 | | -0.7 | 5.1 | |
| Other operating activities | 50.6 | -26.8 | 47.7 | 0.5 | 0.2 | 10.1 | 10.4 | 4.8 |
| Cash from operations | 105.1 | 39.5 | 109.4 | 12.0 | 33.2 | 52.8 | -0.7 | 4.1 |
| |
| Capital expenditures [+] | 8.3 | 4.6 | 6.8 | -4.6 | -5.3 | -3.6 | -1.7 | -2.2 |
| Purchases of property and equipment | 8.3 | 4.6 | 6.8 | -4.6 | -5.3 | -3.6 | -1.7 | -2.2 |
| Sales of property and equipment | | | | | | 3.7 | | |
| Purchases of intangible assets | | | | | | | | -0.1 |
| Acquisitions | 98.3 | 37.4 | 207.7 | -184.1 | -62.4 | -24.4 | -20.0 | -8.4 |
| Other cash from investing | -213.2 | -84.0 | -428.7 | | | | | |
| Cash from investing | -106.6 | -42.0 | -214.2 | -188.7 | -67.8 | -24.3 | -21.7 | -10.7 |
| |
| Issuance of common stock, net | | | | 172.9 | 76.6 | | | |
| Option exercises | 2.5 | 1.1 | 3.9 | 3.2 | 1.0 | 1.2 | 3.0 | 0.3 |
| Financing costs | | 3.0 | | -0.4 | -0.9 | -2.9 | | |
| Other cash from financing | -84.9 | 30.5 | 142.1 | 47.8 | -25.3 | 15.5 | 29.4 | -2.3 |
| Cash from financing | -87.5 | 26.3 | 138.2 | 218.0 | 51.2 | 17.2 | 26.4 | -2.6 |
| |
| Free cash flow | 113.4 | 44.1 | 116.2 | 7.4 | 27.9 | 49.2 | -2.5 | 1.9 |
| Per share (diluted) | $7.01 | $2.75 | $7.29 | $0.52 | $2.25 | $4.23 | ($0.22) | $0.17 |
| |
| Cash paid for interest | 8.0 | 5.1 | 2.4 | 2.3 | 4.3 | 2.3 | 2.3 | 0.8 |
| Cash paid for income taxes | 1.5 | 17.8 | 10.6 | 7.3 | 4.1 | 6.7 | 5.1 | 0.9 |