| 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 |
| Revenue | 725.4 | 702.4 | 654.6 | 612.7 | 421.4 | 339.5 | 322.5 | 281.9 |
| Revenue growth | 3.3% | 7.3% | 6.8% | 45.4% | 24.1% | 5.3% | 14.4% | 2.4% |
| Costs and expenses: | | | | | | | | |
| Cost of revenue, excluding depreciation and amortization | 164.4 | 144.9 | 162.3 | 175.3 | 81.6 | 64.9 | 44.2 | 31.1 |
| Selling, general and administrative | 185.1 | 207.0 | 219.6 | 257.3 | 149.2 | 130.2 | 112.2 | 88.6 |
| Depreciation and amortization | 267.2 | 280.7 | 239.7 | 224.8 | 114.6 | 117.1 | 118.9 | 74.4 |
| Restructuring charges | 6.6 | 9.0 | 1.1 | 40.1 | | | | |
| Income from operations | 102.1 | 60.8 | 31.9 | -84.8 | 76.0 | 27.3 | 47.2 | 87.8 |
| Operating margin | 14.1% | 8.7% | 4.9% | -13.8% | 18.0% | 8.0% | 14.6% | 31.1% |
| Interest expense, net | -17.8 | -29.0 | -7.1 | -3.4 | -9.1 | -21.7 | -40.4 | 0.1 |
| Loss from early extinguishment of debt | -35.7 | | | -17.8 | | -51.8 | | -7.7 |
| Income (loss) before income taxes | 48.7 | 33.4 | 25.4 | -105.8 | 65.9 | -46.0 | 6.8 | 78.4 |
| Income tax (expense) benefit | -18.3 | -9.2 | -6.9 | 37.5 | -26.9 | 17.9 | -4.3 | -31.0 |
| Tax rate | 37.6% | 27.5% | 27.2% | 35.4% | 40.8% | 38.9% | 63.2% | 39.5% |
| Equity in earnings from joint ventures, net of tax | 3.9 | 0.9 | | | | | | |
| Net income | 26.5 | 23.3 | 18.5 | -68.3 | 39.0 | -28.1 | 2.5 | 47.4 |
| Preferred stock dividends | -4.0 | -4.0 | -4.0 | -3.6 | | | | |
| Net income less preferred stock dividends | 22.5 | 19.3 | 14.5 | -71.9 | 39.0 | -28.1 | | |
| Income allocated to participating securities | 1.0 | 0.8 | 0.6 | | | | | |
| Net income (loss) available to common stockholders | 22.5 | 19.3 | 14.5 | -71.9 | 39.0 | -28.1 | | |
| |
| Earnings (loss) per share: | | | | | | | | |
| Basic earnings (loss) per share (in dollars per share) | $0.34 | $0.26 | $0.19 | ($1.00) | $0.85 | ($0.61) | $0.05 | $1.07 |
| Diluted earnings (loss) per share (in dollars per share) | $0.34 | $0.26 | $0.18 | ($1.00) | $0.84 | ($0.61) | $0.05 | $1.06 |
| |
| Weighted average common shares outstanding: | | | | | | | | |
| Basic (in shares) | 63.1 | 71.0 | 74.9 | 71.8 | 46.1 | 45.9 | 45.7 | 44.2 |
| Diluted (in shares) | 63.8 | 71.5 | 75.9 | 71.8 | 46.4 | 45.9 | 46.1 | 44.9 |