| 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/A | 10-K | 10-K | 10-K | 10-K |
| Net income | 195.6 | 177.4 | 131.8 | 77.1 | 99.6 | 32.6 | 33.8 | 24.1 |
| Depreciation and amortization | 37.3 | 40.9 | 42.6 | 34.1 | 25.1 | 26.1 | 29.4 | 26.6 |
| Asset impairment charges | | | | | | | | 7.1 |
| Stock-based compensation | | | | | | | 18.1 | 17.2 |
| Deferred taxes | | | | | | | 12.2 | -9.7 |
| Change in working capital [+] | -5.2 | 22.7 | 5.1 | -32.0 | 26.8 | 8.1 | -11.4 | -7.1 |
| Accounts receivable | | | | | | | 5.5 | -19.1 |
| Inventories | | | | | | | -0.4 | -1.4 |
| Other current assets | | | | | | | -15.5 | -3.5 |
| Deferred revenues | | | | | | | | 4.2 |
| Other | -5.2 | 22.7 | 5.1 | -32.0 | 26.8 | 8.1 | -1.0 | 12.7 |
| Other operating activities | 97.9 | -58.1 | 140.4 | 42.5 | 35.3 | 29.8 | -19.9 | -5.9 |
| Cash from operations | 325.6 | 182.9 | 319.9 | 121.7 | 186.7 | 96.6 | 62.2 | 52.4 |
| |
| Capital expenditures | 199.9 | 39.2 | 27.7 | 69.1 | 32.3 | 24.7 | -29.9 | -20.0 |
| Purchases of property and equipment | 199.9 | 39.2 | 27.7 | 69.1 | 32.3 | 24.7 | -29.9 | -20.0 |
| Purchases of short-term investments, net | 509.8 | 596.6 | 336.2 | 281.8 | 156.3 | 178.0 | 8.1 | 2.5 |
| Purchases of short-term investments | 246.0 | 374.5 | 153.9 | 124.3 | 94.9 | 142.4 | | -21.6 |
| Sales of short-term investments | 263.8 | 222.1 | 182.3 | 157.5 | 61.4 | 35.7 | 8.1 | 24.1 |
| Other cash from investing | -887.6 | -828.9 | -352.0 | -386.7 | -254.7 | -336.5 | -2.3 | -1.2 |
| Cash from investing | -177.9 | -193.1 | 11.9 | -35.8 | -66.1 | -133.7 | -24.1 | -18.7 |
| |
| Cash dividends paid | | | | | | | -36.6 | -36.3 |
| Repurchase of common stock, net | -37.5 | -162.7 | 2.6 | -81.1 | 1.9 | 1.6 | 1.4 | 1.1 |
| Financing costs | | | | 0.7 | | | -0.7 | -0.9 |
| Other cash from financing | -24.8 | -154.4 | 37.3 | -81.1 | -92.8 | -38.7 | 170.3 | -8.5 |
| Cash from financing | -62.3 | -317.1 | 39.9 | -162.9 | -90.9 | -37.1 | 135.9 | -42.9 |
| |
| Free cash flow | 525.5 | 222.2 | 347.5 | 190.8 | 219.0 | 121.3 | 32.3 | 32.4 |
| Per share (diluted) | $5.96 | $2.62 | $4.13 | $2.11 | $2.47 | $1.55 | $0.42 | $0.42 |
| |
| Cash paid for interest | 9.6 | 9.9 | 12.3 | 10.7 | 8.9 | 9.3 | 1.6 | 1.4 |
| Cash paid for income taxes | 90.0 | 55.5 | 45.6 | 7.4 | 10.1 | 14.6 | 12.5 | 21.7 |