| In millions, except per share items | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | 65.8 | 86.6 | 92.7 | 71.6 | 46.2 | 77.9 | 70.5 | 53.7 |
| Depreciation and amortization [+] | 1.0 | 1.0 | 0.9 | 1.0 | 1.0 | 1.2 | 1.3 | 1.3 |
| Depreciation | 1.0 | 1.0 | 0.9 | 1.0 | 1.0 | 1.2 | 1.3 | 1.3 |
| Asset impairment charges | 1.5 | 1.6 | | | | 1.3 | 1.2 | 0.9 |
| Stock-based compensation | 2.3 | 3.3 | 2.4 | 2.1 | 2.0 | 1.6 | 1.2 | 1.5 |
| Deferred taxes | 1.3 | 1.7 | 0.9 | -1.5 | 12.8 | -2.2 | 1.4 | -1.4 |
| Change in working capital [+] | -7.9 | -9.1 | -4.6 | 4.7 | -1.7 | 3.9 | 4.3 | 6.1 |
| Income taxes | -6.8 | -2.8 | -0.2 | 5.2 | | | | |
| Other | -1.1 | -6.3 | -4.4 | -0.5 | -1.7 | 3.9 | 4.3 | 6.1 |
| Other operating activities | -26.0 | -21.7 | -13.5 | 20.3 | 70.4 | 30.6 | 12.9 | 78.6 |
| Cash from operations | 38.0 | 63.4 | 78.8 | 98.3 | 130.8 | 114.2 | 92.9 | 140.7 |
| |
| Capital expenditures [+] | -1.3 | -0.9 | -1.0 | -1.1 | -0.5 | -1.6 | -1.0 | -1.0 |
| Purchases of property and equipment | -1.3 | -0.9 | -1.0 | -1.1 | -0.5 | -1.6 | -1.0 | -1.0 |
| Sales of property and equipment | 0.0 | | | | | | | 10.5 |
| Sales of short-term investments, net [+] | 123.9 | 152.1 | 169.3 | 82.7 | 166.4 | 57.0 | 129.1 | -29.3 |
| Purchases of short-term investments | -219.5 | -213.2 | -189.3 | -257.5 | -171.2 | -251.8 | -148.2 | -229.9 |
| Sales of short-term investments | 343.4 | 365.2 | 358.6 | 340.2 | 337.6 | 308.8 | 277.3 | 200.6 |
| Other cash from investing | -51.7 | -107.8 | -156.6 | -110.7 | -217.4 | -105.8 | -178.0 | -121.5 |
| Cash from investing | 71.0 | 43.4 | 11.7 | -29.1 | -51.5 | -50.5 | -49.8 | -141.3 |
| |
| Cash dividends paid | -99.9 | -88.8 | -87.0 | -84.5 | -82.6 | -76.1 | -68.6 | -37.1 |
| Option exercises | | | 0.0 | 0.1 | | 0.8 | 1.8 | 2.7 |
| Other cash from financing | 0.0 | 0.0 | 0.0 | 0.1 | | 2.7 | 5.9 | 8.2 |
| Cash from financing | -100.0 | -88.8 | -87.0 | -84.4 | -82.6 | -74.3 | -64.5 | -31.6 |
| |
| Free cash flow | 36.7 | 62.5 | 77.8 | 97.1 | 130.3 | 112.6 | 91.9 | 139.7 |
| Per share (diluted) | $1.89 | $3.23 | $4.03 | $5.04 | $6.77 | $5.86 | $4.81 | $7.38 |
| |
| Cash paid for income taxes | 18.2 | 20.6 | 20.9 | 11.2 | 28.3 | 31.5 | 23.9 | 19.9 |