| 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 | 14.6 | 15.5 | 10.1 | 11.0 | 11.2 | 5.8 | 6.7 | 6.1 |
| Depreciation and amortization [+] | 1.8 | 1.9 | 2.0 | 2.1 | 2.1 | 1.8 | 1.7 | 1.6 |
| Depreciation | 1.7 | 1.7 | 1.6 | 1.6 | 1.5 | 1.4 | 1.3 | 1.3 |
| Amortization of intangible assets | 0.2 | 0.2 | 0.4 | 0.5 | 0.6 | 0.3 | 0.3 | 0.4 |
| Asset impairment charges | | | | 0.3 | 0.0 | 0.1 | 0.0 | 0.1 |
| Change in working capital [+] | 15.0 | 12.6 | 8.0 | 8.4 | 10.9 | -0.7 | -0.5 | 3.7 |
| Accounts payable | | | | | | 0.2 | 1.0 | 0.1 |
| Other | 15.0 | 12.6 | 8.0 | 8.4 | 10.9 | -0.9 | -1.5 | 3.7 |
| Other operating activities | -9.3 | 27.9 | -37.1 | -16.9 | -4.3 | 11.4 | -2.7 | 2.9 |
| Cash from operations | 22.1 | 57.9 | -17.0 | 4.8 | 20.0 | 18.4 | 5.1 | 14.5 |
| |
| Capital expenditures [+] | -1.2 | -0.8 | -1.1 | -2.8 | -1.5 | -3.1 | -1.2 | -2.7 |
| Purchases of property and equipment | -1.2 | -0.8 | -1.1 | -2.8 | -1.5 | -3.1 | -1.2 | -2.7 |
| Sales of property and equipment | 0.1 | 0.0 | | 0.3 | 1.1 | | | |
| Acquisitions | | | | | | 22.4 | | |
| Purchases of short-term investments, net | -44.0 | -217.4 | -63.8 | -28.5 | 22.4 | 30.2 | 4.9 | 0.5 |
| Purchases of short-term investments | -105.9 | -271.3 | -112.0 | -113.1 | -64.1 | -30.6 | -66.4 | -63.2 |
| Sales of short-term investments | 62.0 | 53.9 | 48.1 | 84.6 | 86.5 | 60.8 | 71.2 | 63.7 |
| Other cash from investing | -117.7 | -18.1 | -106.6 | -18.2 | -69.9 | -40.5 | -55.2 | -55.8 |
| Cash from investing | -162.8 | -236.3 | -171.5 | -49.2 | -47.8 | 9.0 | -51.5 | -58.0 |
| |
| Cash dividends paid | -3.9 | -3.6 | -3.6 | -3.3 | -3.0 | -2.5 | -2.1 | -1.8 |
| Repurchase of common stock, net | 0.0 | 0.0 | 0.0 | -5.6 | | | | |
| Other cash from financing | 112.9 | 185.9 | 209.4 | 68.8 | 32.6 | -16.3 | 47.6 | 45.7 |
| Cash from financing | 109.0 | 182.4 | 205.9 | 59.9 | 29.5 | -18.8 | 45.5 | 43.9 |
| |
| Free cash flow | 20.9 | 57.1 | -18.1 | 2.0 | 18.5 | 15.3 | 3.9 | 11.8 |
| Per share (diluted) | $2.75 | $7.57 | ($2.42) | $0.27 | $2.39 | $2.18 | $0.57 | $1.76 |
| |
| Cash paid for interest | 3.1 | 3.3 | 4.3 | 5.5 | 3.6 | 2.8 | 3.1 | 3.5 |