| 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 | 88.1 | 89.6 | 89.4 | 70.0 | 54.3 | 52.1 | 54.1 | 53.0 |
| Depreciation and amortization [+] | 5.8 | 5.8 | 5.0 | 5.1 | 5.9 | 6.2 | 6.1 | 6.1 |
| Depreciation | 5.8 | 5.8 | 5.0 | 5.1 | 5.9 | 6.2 | 6.1 | 6.1 |
| Asset impairment charges | | | 0.3 | 0.5 | | 0.4 | 1.4 | |
| Stock-based compensation | 3.1 | 3.3 | 2.5 | 2.2 | 2.1 | 2.0 | 1.8 | 1.5 |
| Tax benefit from stock-based compensation | -0.6 | -0.2 | -0.5 | -0.5 | -0.6 | | | |
| Deferred taxes | 2.2 | 2.6 | 4.9 | -1.2 | 14.9 | 3.8 | 6.6 | 4.6 |
| Change in working capital | 10.9 | 7.3 | 8.4 | 1.3 | 2.1 | 4.6 | -8.9 | 24.4 |
| Other | 10.9 | 7.3 | 8.4 | 1.3 | 2.1 | 4.6 | -8.9 | 24.4 |
| Other operating activities | -7.3 | -18.6 | -5.0 | 0.3 | -2.7 | -3.9 | -13.3 | -36.2 |
| Cash from operations | 102.3 | 89.8 | 105.0 | 77.6 | 76.1 | 65.3 | 47.9 | 53.4 |
| |
| Capital expenditures [+] | -3.3 | -5.5 | -4.7 | -10.2 | -6.6 | -5.5 | -3.0 | -2.3 |
| Purchases of property and equipment | -3.3 | -5.5 | -4.7 | -10.2 | -6.6 | -5.5 | -3.0 | -2.3 |
| Sales of property and equipment | | | | 3.9 | 3.1 | | | |
| Acquisitions | | | | | | | 20.0 | |
| Purchases of short-term investments, net | 852.3 | 630.7 | 355.7 | -74.0 | -84.6 | -73.1 | -106.0 | 30.9 |
| Purchases of short-term investments | 560.7 | 461.4 | 209.6 | -130.9 | -159.3 | -196.2 | -175.3 | -31.3 |
| Sales of short-term investments | 291.6 | 169.2 | 146.1 | 56.8 | 74.7 | 123.0 | 69.3 | 62.2 |
| Other cash from investing | -1,040.1 | -910.4 | -459.8 | -88.1 | -83.6 | -182.7 | -95.1 | |
| Cash from investing | -191.2 | -285.3 | -108.8 | -168.5 | -171.7 | -261.3 | -184.1 | -24.7 |
| |
| Cash dividends paid | -36.1 | -36.7 | -35.5 | -29.6 | -27.1 | -25.7 | -25.3 | -24.5 |
| Repurchase of common stock, net | -58.7 | -36.5 | -19.4 | -20.3 | 28.4 | -3.2 | -7.1 | -28.0 |
| Option exercises | 0.7 | 0.2 | 0.5 | 1.2 | 0.7 | 1.2 | 3.0 | 0.6 |
| Other cash from financing | 290.4 | 657.4 | 76.4 | 182.4 | 89.4 | 244.0 | 93.4 | 86.7 |
| Cash from financing | 194.9 | 584.0 | 20.9 | 131.4 | 89.9 | 214.0 | 58.1 | 33.7 |
| |
| Free cash flow | 99.0 | 84.3 | 100.3 | 67.4 | 69.6 | 59.8 | 44.9 | 51.0 |
| Per share (diluted) | $6.42 | $5.27 | $6.14 | $4.36 | $4.51 | $4.01 | $2.96 | $3.29 |
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