| In millions, except per share items | Mar-31-11 | Dec-31-10 | Sep-30-10 | Jun-30-10 | Mar-31-10 | Dec-31-09 | Sep-30-09 | Jun-30-09 |
| | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q | 10-Q |
| Net revenue | 760.8 | 734.0 | 737.2 | 708.8 | 679.4 | 654.3 | 665.1 | 637.3 |
| Net revenue growth | 12.0% | 12.2% | 10.8% | 11.2% | 10.8% | 10.2% | -2.1% | 11.6% |
| Compensation and benefits | 537.1 | | | | 480.3 | | | |
| Operating expenses | 97.0 | | | | 86.5 | | | |
| Insurance expense | 26.5 | | | | 22.1 | | | |
| Selling, general and administrative expenses | 17.8 | | | | 16.9 | | | |
| Depreciation and amortization expense | 17.5 | 16.9 | 16.5 | 15.7 | 16.2 | 15.7 | 15.7 | 16.2 |
| Income from operations | 64.9 | 63.9 | 62.8 | 61.8 | 57.4 | 54.5 | 55.5 | 55.7 |
| Operating margin | 8.5% | 8.7% | 8.5% | 8.7% | 8.4% | 8.3% | 8.3% | 8.7% |
| Interest income from restricted assets | 0.4 | 0.7 | 0.7 | 0.9 | 0.9 | 1.0 | 1.1 | 1.1 |
| Interest expense | -4.8 | -4.7 | -4.9 | -5.1 | -8.3 | -10.2 | -10.3 | -10.3 |
| Realized (loss) gain on investments | 0.0 | 1.6 | 0.7 | 0.1 | 0.1 | 0.1 | 0.5 | 0.8 |
| Interest and other (expense) income | -1.7 | | | | 0.3 | | | |
| Income before income taxes and equity in earnings of unconsolidated subsidiary | 58.7 | 61.6 | 59.7 | 38.8 | 50.3 | 45.7 | 47.3 | 47.8 |
| Income tax expense | -22.7 | -21.8 | -23.0 | -15.0 | -19.4 | -12.5 | -18.5 | -18.9 |
| Tax rate | 38.6% | 35.3% | 38.5% | 38.5% | 38.6% | 27.4% | 39.2% | 39.5% |
| Income before equity in earnings of unconsolidated subsidiary | 36.1 | 39.9 | 36.7 | 23.9 | 30.9 | 33.2 | 28.8 | 28.9 |
| Equity in earnings of unconsolidated subsidiary | 0.1 | | | | 0.1 | | | |
| Net income | 36.2 | | | | 31.0 | | | |
| |
| Other comprehensive income, net of tax: | | | | | | | | |
| Unrealized holding gains during the period | 0.6 | | | | 0.4 | | | |
| |
| Unrealized gains on derivative financial instruments | | | | | | | | |
| Comprehensive income | | | | | | | | |
| Basic earnings per common share (in dollars per share) | $0.82 | $0.91 | $0.83 | $0.54 | $0.71 | $0.78 | $0.67 | $0.69 |
| Diluted earnings per common share (in dollars per share) | $0.80 | $0.89 | $0.82 | $0.54 | $0.70 | $0.75 | $0.66 | $0.67 |
| |
| Weighted average common shares outstanding, basic (in shares) | 44.2 | 44.0 | 44.1 | 44.0 | 43.6 | 42.6 | 42.8 | 42.4 |
| Weighted average common shares outstanding, diluted (in shares) | 45.0 | 44.7 | 44.7 | 44.7 | 44.5 | 43.6 | 43.8 | 43.3 |
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| Restructuring charges | | | | | | | | |
| Net income | | | | | | | | |
| Comprehensive income | | | | | | | | |
| Loss on early debt extinguishment | | | | | | | | |
| Interest and other (expense) income | | | | | | | | |