| In millions, except per share items | Dec-31-20 | Sep-30-20 | Jun-05-20 | Mar-31-20 | Dec-31-19 | Sep-30-19 | Jun-30-19 | Jun-05-19 |
| | 10-K | 10-Q | 8-K | 10-Q | 10-K | 10-Q | 10-Q | 8-K |
| Revenue | 873.5 | 796.3 | 729.9 | 783.7 | 800.2 | 780.7 | 763.3 | 763.3 |
| Revenue growth | 9.1% | 2.0% | -4.4% | 8.5% | 9.7% | 8.8% | 5.6% | |
| Operating expenses: | | | | | | | | |
| Cost of revenue | | | | | | | | |
| Selling, general and administrative expenses | 120.7 | 115.4 | 110.0 | 107.0 | 103.5 | 95.5 | 98.8 | 98.8 |
| Transaction-related costs | | -45.1 | | 0.6 | 1.3 | 0.6 | | |
| Depreciation and amortization expense | 33.6 | 33.3 | 32.5 | 32.3 | 29.4 | 29.3 | 28.6 | 28.6 |
| Loss on disposal of fixed assets | 0.1 | 0.0 | 0.2 | 0.0 | 0.2 | 0.3 | 0.6 | 0.6 |
| Income from operations | 97.1 | 124.2 | 43.6 | 63.2 | 101.4 | 95.8 | 88.0 | 88.0 |
| Operating margin | 11.1% | 15.6% | 6.0% | 8.1% | 12.7% | 12.3% | 11.5% | 11.5% |
| Interest expense, net | -7.0 | -10.7 | -11.9 | -13.5 | -14.2 | -13.0 | -12.5 | -12.5 |
| Loss on modification or extinguishment of debt | -1.0 | | | | -2.1 | -1.9 | | |
| Foreign currency losses, net | -13.5 | -9.1 | -10.8 | 7.8 | -4.1 | 5.4 | -9.7 | -9.7 |
| Other (expense) income, net | | 0.0 | | 0.0 | 0.2 | 0.0 | 0.0 | |
| Income before income taxes and equity in income of unconsolidated joint ventures | 76.2 | 104.3 | 21.0 | 57.5 | 81.3 | 86.4 | 65.9 | 65.9 |
| Provision for income taxes | 24.9 | 13.1 | 7.1 | 16.9 | 6.5 | 3.4 | 24.8 | 24.8 |
| Tax rate | 32.7% | 12.5% | 33.9% | 29.3% | 8.0% | 3.9% | 37.7% | 37.7% |
| Equity in income of unconsolidated joint ventures, net of tax | | | | | | | | |
| Net income | 51.3 | 91.3 | | 40.7 | 74.8 | 83.0 | 41.1 | |
| Net income attributable to noncontrolling interest | | | | | | | 0.1 | -0.1 |
| Net income attributable to PRA Health Sciences, Inc. | 51.3 | 91.3 | 13.9 | 40.7 | 74.8 | 83.0 | 41.1 | 41.1 |
| |
| Net income per share attributable to common stockholders: | | | | | | | | |
| Basic (in dollars per share) | $0.80 | $1.44 | $0.22 | $0.65 | $1.19 | $1.28 | $0.63 | $0.63 |
| Diluted (in dollars per share) | $0.78 | $1.41 | $0.22 | $0.63 | $1.15 | $1.25 | $0.62 | $0.62 |
| |
| Weighted average common shares outstanding: | | | | | | | | |
| Basic (in shares) | 63.4 | 63.4 | 63.2 | 62.9 | 64.5 | 64.8 | 65.3 | 65.3 |
| Diluted (in shares) | 64.8 | 64.9 | 64.5 | 64.3 | 66.0 | 66.2 | 66.8 | 66.8 |