| 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 | 83.3 | 10.1 | -145.1 | -56.7 | 0.6 | 34.1 | 57.1 | 60.5 |
| Depreciation and amortization | 82.6 | 109.1 | 113.0 | 122.0 | 111.5 | 66.3 | 64.4 | 64.3 |
| Stock-based compensation | 7.8 | 6.4 | 6.4 | 10.2 | 14.8 | 15.8 | 13.4 | 8.8 |
| Deferred taxes | 5.4 | 16.6 | 8.8 | -22.9 | 12.1 | -2.7 | 9.8 | 28.3 |
| Change in working capital [+] | 12.8 | -4.5 | 25.0 | 71.7 | -53.7 | -24.3 | -37.7 | -7.3 |
| Accounts receivable | 59.6 | -11.3 | 6.8 | -58.9 | -9.2 | -65.8 | -75.8 | -32.9 |
| Inventories | -14.3 | 0.8 | 5.1 | 0.4 | -2.1 | -7.3 | 0.3 | 13.4 |
| Accounts payable | -9.8 | 7.4 | -41.0 | 140.0 | -21.5 | 37.7 | | |
| Other | -22.7 | -1.4 | 54.0 | -9.8 | -20.9 | 11.1 | 37.7 | 12.2 |
| Other operating activities | -136.3 | -115.7 | 260.4 | -12.8 | 1.1 | 57.0 | -33.9 | -87.5 |
| Cash from operations | 55.6 | 21.9 | 268.5 | 111.4 | 86.4 | 146.2 | 73.1 | 67.0 |
| |
| Capital expenditures [+] | -121.6 | -94.8 | -93.3 | -106.8 | -111.1 | -67.7 | -91.0 | -44.2 |
| Purchases of property and equipment | -121.6 | -94.8 | -93.3 | -106.8 | -111.1 | -67.7 | -91.0 | -44.2 |
| Sales of property and equipment | 26.1 | 94.8 | 16.7 | 37.1 | 16.2 | 10.2 | 12.9 | 13.1 |
| Acquisitions | | | | -6.2 | -55.0 | | | |
| Purchases of short-term investments, net | -49.1 | -10.0 | 15.0 | 35.0 | 65.0 | -4.5 | -79.7 | -75.7 |
| Purchases of short-term investments | -94.1 | -10.0 | -10.0 | | -10.0 | -124.5 | -129.7 | -105.0 |
| Sales of short-term investments | 45.0 | | 25.0 | 35.0 | 75.0 | 120.0 | 50.0 | 29.3 |
| Other cash from investing | 133.6 | -11.5 | 20.3 | 0.6 | 45.2 | 2.8 | 61.3 | 76.0 |
| Cash from investing | -11.0 | -21.5 | -41.3 | -40.3 | -39.6 | -59.2 | -96.4 | -30.7 |
| |
| Cash dividends paid | -23.3 | -23.8 | -23.7 | -24.3 | -22.4 | -20.7 | -20.6 | -20.4 |
| Repurchase of common stock, net | -70.9 | -2.7 | -0.9 | -36.9 | -16.6 | -7.0 | -5.2 | -3.8 |
| Other cash from financing | -70.1 | 2.1 | -33.1 | -20.4 | 37.1 | -15.0 | -14.5 | -15.2 |
| Cash from financing | -164.3 | -24.4 | -57.7 | -81.6 | -1.9 | -42.6 | -40.3 | -39.4 |
| |
| Free cash flow | -66.0 | -72.9 | 175.2 | 4.6 | -24.7 | 78.5 | -17.8 | 22.8 |
| Per share (diluted) | ($1.26) | ($1.53) | $3.84 | $0.10 | ($0.56) | $1.94 | ($0.44) | $0.57 |
| |
| Cash paid for interest | 11.5 | 14.6 | 18.8 | 17.3 | 14.9 | 11.4 | 13.4 | 14.6 |
| Cash paid for income taxes | 3.8 | 2.1 | 2.8 | 11.9 | 19.1 | 33.9 | 29.9 | 4.3 |