| 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 | 128.3 | 123.4 | 100.3 | 103.0 | 98.9 | 62.7 | 49.7 | 38.3 |
| Depreciation and amortization [+] | 22.1 | 22.9 | 22.3 | 21.4 | 15.4 | 13.9 | 11.7 | 8.9 |
| Depreciation | 10.5 | 11.6 | 12.3 | 11.9 | 9.6 | 8.6 | 7.3 | 5.7 |
| Amortization of intangible assets | 11.6 | 11.3 | 10.0 | 9.5 | 5.9 | 5.2 | 4.4 | 3.2 |
| Stock-based compensation | 9.0 | 7.9 | 7.1 | 4.0 | 3.7 | 2.8 | 1.8 | 1.4 |
| Deferred taxes | -1.3 | 4.7 | -5.3 | 0.1 | 7.1 | 14.1 | 3.0 | 3.0 |
| Change in working capital | 2.6 | -28.1 | -6.6 | -7.4 | 2.2 | -4.2 | -6.3 | -1.3 |
| Other | 2.6 | -28.1 | -6.6 | -7.4 | 2.2 | -4.2 | -6.3 | -1.3 |
| Other operating activities | 5.0 | 31.2 | 45.3 | -32.8 | 75.2 | 164.1 | -80.8 | 11.2 |
| Cash from operations | 165.8 | 162.0 | 163.2 | 88.3 | 202.5 | 253.4 | -20.9 | 61.5 |
| |
| Capital expenditures [+] | -5.0 | -5.0 | -4.2 | -13.2 | -11.6 | -15.0 | -9.0 | -4.1 |
| Purchases of property and equipment | -5.0 | -5.0 | -4.2 | -13.2 | -11.6 | -15.0 | -9.0 | -4.1 |
| Sales of property and equipment | 4.5 | 7.3 | 0.8 | 0.4 | 0.3 | 2.2 | 2.5 | 0.3 |
| Acquisitions | | 228.3 | | -61.5 | | 27.0 | | |
| Purchases of short-term investments, net | 175.2 | -1,150.0 | -629.6 | 359.6 | 161.9 | 202.6 | 117.7 | -9.0 |
| Purchases of short-term investments | -294.9 | -2,309.1 | -1,295.3 | -409.5 | -124.2 | -141.7 | -180.4 | -235.3 |
| Sales of short-term investments | 470.1 | 1,159.0 | 665.7 | 769.1 | 286.2 | 344.3 | 298.1 | 226.3 |
| Other cash from investing | -465.6 | 90.3 | -96.6 | -227.9 | -206.0 | -510.7 | 38.6 | -121.5 |
| Cash from investing | -290.9 | -829.2 | -729.5 | 57.4 | -55.4 | -293.9 | 149.7 | -134.2 |
| |
| Cash dividends paid | -50.9 | -50.8 | -48.0 | -45.2 | -39.0 | -30.7 | -22.7 | -18.6 |
| Repurchase of common stock, net | -9.9 | -33.0 | -12.3 | -24.3 | | | | -6.3 |
| Other cash from financing | -423.1 | 898.5 | 785.9 | 213.0 | -221.5 | 257.8 | -258.7 | 77.5 |
| Cash from financing | -483.9 | 814.7 | 725.6 | 143.6 | -260.5 | 227.1 | -281.4 | 52.6 |
| |
| Free cash flow | 160.8 | 157.0 | 159.0 | 75.1 | 190.9 | 238.4 | -29.9 | 57.4 |
| Per share (diluted) | $2.86 | $2.80 | $2.90 | $1.36 | $3.88 | $5.53 | ($0.84) | $1.97 |