| 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 | 67.4 | 20.0 | 27.8 | 39.5 | 34.0 | 15.1 | 15.7 | 13.5 |
| Depreciation and amortization [+] | 4.1 | 3.2 | 2.8 | 2.5 | 2.4 | 2.3 | 2.3 | 2.4 |
| Depreciation | 1.5 | 2.5 | 2.3 | 1.9 | 2.0 | 2.2 | 2.3 | 2.4 |
| Amortization of intangible assets | 2.6 | 0.6 | 0.5 | 0.5 | 0.4 | 0.1 | 0.0 | |
| Asset impairment charges | | 3.8 | | | | | | |
| Stock-based compensation | 3.0 | 1.4 | 2.1 | 2.5 | 2.3 | 1.2 | 0.7 | 0.6 |
| Deferred taxes | 1.0 | 6.5 | -0.6 | 6.4 | 9.8 | 13.7 | 8.4 | 8.8 |
| Change in working capital [+] | -6.1 | -25.9 | 19.1 | 3.6 | 12.8 | 1.7 | -8.1 | 13.1 |
| Income taxes | 12.0 | -9.3 | 0.8 | 1.5 | 1.7 | -2.5 | 0.3 | 0.1 |
| Other | -18.2 | -16.6 | 18.3 | 2.1 | 11.1 | 4.2 | -8.4 | 13.0 |
| Other operating activities | 28.1 | 22.1 | -25.2 | -1.8 | -6.4 | 3.1 | 8.3 | -17.3 |
| Cash from operations | 97.3 | 31.0 | 26.0 | 52.6 | 54.9 | 37.1 | 27.3 | 21.1 |
| |
| Capital expenditures [+] | -4.3 | -2.0 | -3.9 | -4.4 | -1.9 | -1.1 | -2.0 | -1.3 |
| Purchases of property and equipment | -4.3 | -2.0 | -3.9 | -4.4 | -1.9 | -1.1 | -2.0 | -1.3 |
| Sales of property and equipment | 13.3 | | | 0.0 | | 0.0 | | 0.0 |
| Acquisitions | -0.1 | 149.0 | | | -35.7 | | -181.4 | |
| Sales of short-term investments, net [+] | 9.2 | -141.4 | 0.8 | 73.5 | 60.3 | 6.4 | 177.4 | -66.4 |
| Purchases of short-term investments | -301.6 | -886.1 | -65.2 | -159.5 | -75.0 | -343.5 | -210.7 | -196.1 |
| Sales of short-term investments | 310.8 | 744.7 | 66.1 | 233.1 | 135.3 | 349.9 | 388.1 | 129.7 |
| Other cash from investing | -450.8 | 127.3 | -100.7 | -26.9 | -48.5 | -137.8 | -117.1 | 35.4 |
| Cash from investing | -432.8 | 132.9 | -103.8 | 42.2 | -25.8 | -132.5 | -123.1 | -32.2 |
| |
| Cash dividends paid | -8.9 | -4.6 | -1.2 | -1.2 | -1.2 | -1.2 | -0.9 | |
| Repurchase of common stock, net | -0.5 | -10.4 | -5.9 | -0.7 | -0.5 | -0.2 | -0.3 | -0.1 |
| Option exercises | | | | 0.0 | 0.0 | | 0.0 | |
| Financing costs | | | | | | 0.0 | | |
| Other cash from financing | -292.2 | 273.3 | 364.2 | -97.6 | -27.9 | 105.3 | 104.0 | 7.3 |
| Cash from financing | -301.5 | 258.2 | 357.1 | -99.5 | -29.7 | 103.9 | 102.8 | 7.2 |
| |
| Free cash flow | 93.0 | 29.0 | 22.1 | 48.3 | 53.0 | 36.1 | 25.3 | 19.9 |
| Per share (diluted) | $2.06 | $0.94 | $0.73 | $1.59 | $1.75 | $1.20 | $0.85 | $0.67 |
| |
| Cash paid for income taxes | 10.3 | 10.6 | 7.9 | 4.4 | 0.0 | 0.4 | 0.2 | 0.1 |