| In millions, except per share items | Jun-30-23 | Mar-31-23 | Dec-31-22 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 |
| | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q |
| Net income | 50.9 | 48.1 | 44.8 | 42.8 | 42.2 | 42.0 | 42.4 | 40.6 |
| Depreciation and amortization | 1.2 | 1.2 | 1.1 | 1.2 | 1.2 | 0.9 | 0.6 | 0.5 |
| Stock-based compensation | 1.0 | 1.0 | 1.1 | 1.0 | 1.0 | 1.6 | 1.4 | 1.3 |
| Deferred taxes | -1.9 | 0.9 | -1.9 | 0.3 | 0.7 | -6.8 | -4.0 | -4.4 |
| Change in working capital | 8.3 | -6.0 | 2.3 | -6.2 | -9.6 | -1.2 | -7.9 | -0.9 |
| Other | 8.3 | -6.0 | 2.3 | -6.2 | -9.6 | -1.2 | -7.9 | -0.9 |
| Other operating activities | 0.8 | -2.1 | -1.4 | -7.7 | -17.3 | -13.0 | -3.9 | 17.9 |
| Cash from operations | 60.3 | 43.2 | 46.0 | 31.5 | 18.2 | 23.5 | 28.7 | 55.0 |
| |
| Capital expenditures | -0.5 | -0.5 | -0.5 | -0.7 | -0.8 | -0.8 | -0.7 | -0.5 |
| Purchases of property and equipment | -0.5 | -0.5 | -0.5 | -0.7 | -0.8 | -0.8 | -0.7 | -0.5 |
| Purchases of short-term investments, net | 11.1 | 12.7 | 14.5 | 16.9 | 20.2 | -16.4 | -33.9 | -41.9 |
| Purchases of short-term investments | | | -2.6 | | -32.3 | -72.6 | -99.7 | -107.1 |
| Sales of short-term investments | 12.1 | 13.7 | 17.1 | 26.1 | 52.4 | 56.2 | 65.8 | 65.2 |
| Other cash from investing | -543.5 | -784.2 | -850.9 | -869.9 | -783.2 | -518.7 | -420.4 | -154.4 |
| Cash from investing | -532.9 | -772.0 | -836.9 | -853.8 | -763.8 | -535.9 | -455.0 | -196.8 |
| |
| Cash dividends paid | -11.2 | -10.4 | -15.3 | -15.3 | -15.3 | -48.5 | -51.9 | -49.4 |
| Financing costs | | | | -1.5 | | | | |
| Other cash from financing | 511.8 | 580.7 | 639.5 | 623.0 | 495.0 | 520.0 | 501.9 | 269.3 |
| Cash from financing | 502.0 | 571.8 | 625.6 | 609.2 | 479.7 | 582.7 | 561.2 | 331.2 |
| |
| Free cash flow | 59.8 | 42.7 | 45.5 | 30.7 | 17.4 | 22.7 | 27.9 | 54.5 |
| Per share (diluted) | $3.48 | $2.49 | $2.65 | $1.85 | $1.05 | $1.42 | $1.93 | $4.13 |
| |
| Cash paid for interest | 2.7 | 0.9 | | | 3.6 | 4.3 | 4.5 | 4.6 |
| Cash paid for income taxes | 0.7 | | | | 14.6 | | 10.5 | 5.8 |