| 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 | 298.2 | 213.5 | 71.1 | 40.0 | 67.3 | 59.7 | 18.7 | 44.9 |
| Depreciation and amortization [+] | 140.0 | 124.2 | 118.4 | 112.5 | 108.6 | 103.1 | 103.1 | 93.0 |
| Depreciation | 127.1 | 118.9 | 114.4 | 108.1 | 104.1 | 98.5 | 98.8 | 89.0 |
| Amortization of intangible assets | 12.9 | 5.4 | 4.0 | 4.4 | 4.5 | 4.5 | 4.2 | 4.0 |
| Stock-based compensation | 12.8 | 11.4 | 10.5 | 9.5 | 8.4 | 7.0 | 7.6 | 8.0 |
| Deferred taxes | -6.3 | -7.6 | 7.7 | 5.4 | 1.9 | -10.2 | 9.5 | 16.4 |
| Change in working capital [+] | -15.8 | -111.1 | -47.8 | 0.2 | -14.4 | -21.8 | -19.0 | -6.2 |
| Accounts receivable | -10.3 | -122.8 | -38.1 | 13.7 | -23.6 | -19.6 | -23.8 | 2.3 |
| Income taxes | -5.0 | 13.1 | -1.7 | -8.7 | 12.2 | -2.1 | 6.2 | -8.9 |
| Other | -0.4 | -1.5 | -8.0 | -4.8 | -3.0 | -0.1 | -1.4 | 0.4 |
| Other operating activities | 41.8 | 93.1 | 46.1 | 2.7 | 83.5 | 14.2 | -7.9 | -7.0 |
| Cash from operations | 470.8 | 323.5 | 206.0 | 170.4 | 255.3 | 151.9 | 111.9 | 149.1 |
| |
| Capital expenditures [+] | -165.5 | -78.5 | -57.5 | -102.4 | -54.1 | -75.6 | -78.7 | -86.9 |
| Purchases of property and equipment | -148.2 | -58.4 | -43.2 | -91.0 | -44.0 | -65.8 | -68.3 | -78.4 |
| Capitalized product costs | -17.3 | -20.1 | -14.2 | -11.5 | -10.1 | -9.8 | -10.5 | -8.5 |
| Sales of property and equipment | 19.7 | 13.8 | 13.3 | 13.5 | 4.3 | 4.3 | 8.8 | 6.6 |
| Acquisitions | 2.3 | -239.4 | | | | | -24.8 | -29.8 |
| Purchases of short-term investments, net | -118.0 | 17.2 | 51.6 | -9.3 | -49.8 | 0.4 | 4.8 | -15.5 |
| Purchases of short-term investments | -182.4 | -56.0 | -165.1 | -129.7 | -108.5 | -73.5 | -69.4 | -61.4 |
| Sales of short-term investments | 64.3 | 73.2 | 216.7 | 120.4 | 58.7 | 73.8 | 74.2 | 45.8 |
| Other cash from investing | 0.5 | -16.3 | | | 4.7 | 2.5 | 2.8 | |
| Cash from investing | -261.1 | -303.2 | 7.5 | -98.2 | -95.0 | -68.5 | -87.2 | -125.6 |
| |
| Cash dividends paid | -10.8 | -8.1 | -8.2 | -8.2 | -8.2 | -8.3 | -8.3 | -6.8 |
| Repurchase of common stock, net | -65.0 | -83.1 | -6.6 | -9.1 | -9.4 | -6.0 | -9.5 | -12.8 |
| Financing costs | -1.0 | -0.3 | | -0.6 | -0.2 | -0.9 | | -0.9 |
| Other cash from financing | -53.1 | -156.7 | -96.7 | -43.7 | -73.5 | -64.6 | -58.1 | 3.2 |
| Cash from financing | -128.0 | -247.6 | -111.4 | -60.4 | -91.0 | -77.9 | -75.9 | -15.6 |
| |
| Free cash flow | 322.6 | 265.1 | 162.7 | 79.4 | 211.4 | 86.1 | 43.7 | 70.7 |
| Per share (diluted) | $11.97 | $9.15 | $5.62 | $2.57 | $7.54 | $2.89 | $1.26 | $2.34 |