| In millions, except per share items | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 | Dec-31-10 | Dec-31-09 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Net income | -34.7 | 92.5 | 51.2 | 32.0 | 37.1 | 52.7 | 40.4 | 49.8 |
| Depreciation and amortization | 102.2 | 74.0 | 68.3 | 60.1 | 37.9 | 17.7 | 20.5 | 23.0 |
| Asset impairment charges | 69.4 | | 39.7 | 22.6 | | | 12.6 | |
| Stock-based compensation | 19.8 | 17.9 | 15.6 | 12.5 | 9.2 | 8.1 | 7.5 | 10.8 |
| Tax benefit from stock-based compensation | -1.0 | -4.0 | -3.7 | -4.3 | -2.1 | -1.9 | -0.9 | |
| Deferred taxes | -8.5 | -6.7 | -21.4 | -12.3 | -8.5 | 21.2 | -11.6 | -0.3 |
| Change in working capital [+] | 23.1 | 21.2 | 86.7 | 79.9 | 93.5 | 31.2 | 67.1 | -22.7 |
| Accounts receivable | 2.3 | -4.9 | -12.5 | -29.7 | -39.7 | -13.1 | -13.2 | 3.6 |
| Other current assets | 3.1 | -4.9 | 9.1 | -8.2 | 18.5 | -11.5 | -0.4 | -0.1 |
| Deferred revenues | -10.8 | 0.8 | 33.5 | 48.5 | 58.9 | 34.2 | 22.4 | -47.5 |
| Other | 28.5 | 30.3 | 56.7 | 69.3 | 55.9 | 21.6 | 58.4 | 21.2 |
| Other operating activities | -42.1 | -46.7 | -54.3 | -41.8 | -44.9 | -28.7 | -50.4 | -32.0 |
| Cash from operations | 128.2 | 148.3 | 182.1 | 148.7 | 122.2 | 100.3 | 85.1 | 28.6 |
| |
| Capital expenditures | -23.6 | -22.8 | -35.2 | -27.0 | -17.5 | -10.2 | -8.3 | -7.1 |
| Purchases of property and equipment | -23.6 | -22.8 | -35.2 | -27.0 | -17.5 | -10.2 | -8.3 | -7.1 |
| Acquisitions | -269.2 | -56.6 | -58.9 | | -669.1 | -6.2 | -14.0 | 5.2 |
| Sales of short-term investments | | | | | 10.3 | 9.8 | 22.4 | 14.4 |
| Sales of short-term investments | | | | | 10.3 | 9.8 | 22.4 | 14.4 |
| Other cash from investing | -7.2 | -5.3 | -8.6 | -11.2 | | 1.6 | | -1.0 |
| Cash from investing | -300.0 | -84.8 | -102.7 | -38.2 | -676.3 | -4.9 | 0.1 | 11.5 |
| |
| Cash dividends paid | -53.2 | -50.0 | -35.3 | -30.2 | -23.4 | -20.4 | -15.1 | -25.2 |
| Repurchase of common stock, net | -53.6 | -59.3 | -29.2 | -2.8 | -10.0 | -40.3 | | -0.1 |
| Option exercises | 1.7 | 1.6 | 1.2 | 1.1 | 1.4 | 1.7 | 0.9 | 0.7 |
| Financing costs | -4.2 | -6.4 | | -4.2 | -19.2 | -0.5 | | |
| Other cash from financing | 303.5 | 46.0 | -11.9 | -34.9 | 508.4 | -2.0 | 1.5 | 1.5 |
| Cash from financing | 199.2 | -58.5 | -77.7 | -64.8 | 492.8 | -63.8 | -14.5 | -24.6 |
| |
| Free cash flow | 104.6 | 125.4 | 146.9 | 121.7 | 104.7 | 90.0 | 76.8 | 21.5 |
| Per share (diluted) | $3.26 | $3.72 | $4.32 | $3.58 | $3.09 | $2.62 | $2.22 | $0.63 |