| 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/A | 10-K | 10-K |
| Net income | 190.2 | 149.2 | 102.3 | 155.2 | 156.5 | 107.3 | 104.3 | 112.8 |
| Depreciation and amortization [+] | 68.3 | 69.9 | 62.9 | 52.7 | 41.6 | 42.1 | 38.8 | 24.1 |
| Depreciation | | | | | | | 35.3 | 22.5 |
| Amortization | | | | | | | 3.5 | 1.6 |
| Asset impairment charges | | | | | | | 16.3 | 9.9 |
| Stock-based compensation | | | | | | | 11.4 | 9.6 |
| Deferred taxes | -22.2 | -17.6 | -4.3 | 4.3 | 1.0 | 8.3 | -3.8 | 6.2 |
| Change in working capital [+] | 6.1 | 17.9 | 17.6 | 7.0 | 14.7 | -2.1 | -52.2 | -38.2 |
| Restricted cash | | | | | | | | -2.7 |
| Accounts receivable | | | | | | | -34.7 | -4.2 |
| Inventories | | | | | | | -10.5 | -19.3 |
| Other current assets | | | | | | | 4.6 | -1.2 |
| Accounts payable | | | | | | | 0.0 | -3.8 |
| Accrued expenses | 6.1 | 17.9 | 17.6 | 7.0 | 14.7 | -2.1 | -18.2 | -0.9 |
| Income taxes | | | | | | | 6.6 | -0.7 |
| Other | | | | | | | | -5.4 |
| Other operating activities | -63.8 | 56.9 | 20.4 | -47.3 | -32.2 | 3.4 | 33.0 | -0.5 |
| Cash from operations | 178.5 | 276.3 | 198.8 | 172.0 | 181.6 | 159.1 | 147.8 | 124.0 |
| |
| Capital expenditures [+] | 74.0 | 56.9 | 63.7 | 70.8 | 59.7 | 51.3 | -40.9 | -50.8 |
| Purchases of property and equipment | 74.0 | 56.9 | 63.7 | 70.8 | 59.7 | 51.3 | -40.9 | -50.8 |
| Sales of property and equipment | | | | | 5.0 | | | |
| Acquisitions | 31.4 | 34.5 | 33.5 | 23.8 | 14.8 | 29.9 | -76.1 | -48.5 |
| Sales of short-term investments | 414.7 | 337.8 | 203.4 | 300.8 | 384.4 | 362.9 | 334.7 | 246.4 |
| Sales of short-term investments | 414.7 | 337.8 | 203.4 | 300.8 | 384.4 | 362.9 | 334.7 | 246.4 |
| Other cash from investing | -630.5 | -805.1 | -417.8 | -535.6 | -657.0 | -555.4 | -380.4 | -300.2 |
| Cash from investing | -110.4 | -375.9 | -117.3 | -140.3 | -193.0 | -111.3 | -162.7 | -153.1 |
| |
| Repurchase of common stock, net | -144.5 | | -104.7 | | | | | |
| Option exercises | 41.7 | 63.5 | 72.3 | 31.0 | 39.3 | 11.7 | 5.9 | 5.5 |
| Other cash from financing | 76.2 | 117.6 | 138.3 | 55.5 | 71.9 | 13.4 | 6.3 | 9.8 |
| Cash from financing | -110.0 | 54.1 | -38.7 | 24.4 | 32.6 | 1.6 | 0.5 | 4.3 |
| |
| Free cash flow | 252.5 | 333.2 | 262.5 | 242.7 | 241.3 | 210.4 | 106.9 | 73.2 |
| Per share (diluted) | $2.46 | $3.22 | $2.60 | $2.38 | $2.38 | $2.15 | $1.11 | $0.76 |
| |
| Cash paid for interest | | | | | | | 0.0 | 0.0 |