| 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 | 80.6 | 70.5 | 27.0 | 180.4 | 157.1 | 156.0 | 93.9 | 93.3 |
| Depreciation and amortization [+] | 106.1 | 108.8 | 111.7 | 108.3 | 100.9 | 94.8 | 85.3 | 78.7 |
| Depreciation | 74.2 | 79.7 | 80.0 | 74.6 | 68.4 | 62.2 | 55.6 | 50.7 |
| Amortization | 31.9 | 29.2 | 31.7 | 33.6 | 32.6 | 32.6 | 29.6 | 28.0 |
| Stock-based compensation | 28.1 | 23.1 | 21.0 | 17.3 | 13.8 | 12.1 | 11.6 | 9.2 |
| Deferred taxes | -9.6 | -5.0 | -12.3 | -11.3 | -5.5 | -37.6 | -12.1 | -0.8 |
| Change in working capital [+] | -50.3 | 22.6 | 8.3 | 24.9 | 20.3 | 14.3 | 12.0 | -5.5 |
| Accounts receivable | -4.9 | -34.6 | -27.5 | -15.7 | -14.5 | -18.7 | -0.1 | -13.3 |
| Other current assets | -6.1 | -4.4 | -10.7 | 1.8 | 2.8 | -3.5 | -7.4 | 3.8 |
| Deferred revenues | -37.9 | 60.2 | 3.7 | 23.0 | 12.1 | 9.3 | 7.8 | 3.0 |
| Income taxes | -8.4 | -6.8 | -4.2 | 5.0 | -3.3 | 11.2 | 12.8 | -12.1 |
| Other | 6.9 | 8.2 | 46.9 | 10.8 | 23.3 | 16.0 | -1.1 | 13.1 |
| Other operating activities | 33.6 | 7.3 | 53.9 | 10.9 | 8.0 | 8.6 | 22.5 | -4.8 |
| Cash from operations | 188.5 | 227.3 | 209.6 | 330.4 | 294.7 | 248.2 | 213.2 | 170.1 |
| |
| Capital expenditures [+] | -70.6 | -63.5 | -84.7 | -111.8 | -92.5 | -88.1 | -75.3 | -77.8 |
| Purchases of property and equipment | -70.6 | -63.5 | -84.7 | -111.8 | -92.5 | -88.1 | -75.3 | -77.8 |
| Sales of property and equipment | 10.5 | 5.8 | 11.9 | 7.1 | 1.8 | 4.3 | 1.2 | 0.1 |
| Acquisitions | -210.4 | -53.9 | -8.3 | -53.4 | -67.1 | -21.5 | -228.7 | -77.6 |
| Purchases of short-term investments | -25.1 | -29.9 | -25.7 | -28.0 | -0.8 | | | |
| Purchases of short-term investments | -25.1 | -29.9 | -25.7 | -28.0 | -0.8 | | | |
| Other cash from investing | 17.5 | 24.1 | 23.0 | -2.9 | | | | |
| Cash from investing | -278.0 | -117.4 | -83.8 | -189.1 | -158.5 | -105.3 | -302.8 | -155.4 |
| |
| Repurchase of common stock, net | -182.6 | -213.8 | 217.1 | -31.6 | -126.7 | -162.2 | -112.8 | -128.1 |
| Option exercises | 13.2 | 37.5 | 38.8 | 26.6 | 22.9 | 27.0 | 11.7 | 9.8 |
| Financing costs | | -2.1 | -2.8 | | -0.3 | -1.7 | 1.0 | |
| Other cash from financing | 74.5 | 19.2 | 47.9 | -91.0 | 15.1 | 63.6 | 219.2 | 47.3 |
| Cash from financing | -121.3 | -230.0 | 229.0 | -149.1 | -134.2 | -123.9 | 93.8 | -90.6 |
| |
| Free cash flow | 117.9 | 163.8 | 124.8 | 218.5 | 202.3 | 160.1 | 137.9 | 92.3 |
| Per share (diluted) | $2.02 | $2.69 | $2.07 | $3.71 | $3.43 | $2.66 | $2.28 | $1.48 |
| |
| Cash paid for interest | 40.9 | 32.2 | 35.3 | 43.1 | 46.1 | 44.5 | 37.1 | 38.1 |