| 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 | 8.5 | 19.4 | 19.5 | 21.3 | 20.9 | 23.3 | 19.5 | 21.3 |
| Depreciation and amortization [+] | 2.8 | 2.8 | 2.9 | 3.0 | 2.8 | 2.9 | 2.9 | 2.9 |
| Amortization of intangible assets | 0.1 | 0.1 | 0.2 | 0.2 | 0.2 | 0.2 | 0.3 | 0.3 |
| Stock-based compensation | 1.1 | 1.0 | 1.3 | 1.1 | 1.0 | 0.9 | 1.3 | 1.4 |
| Change in working capital | 0.1 | 1.4 | -2.2 | 0.4 | -0.9 | 0.9 | 0.8 | 3.7 |
| Other | 0.1 | 1.4 | -2.2 | 0.4 | -0.9 | 0.9 | 0.8 | 3.7 |
| Other operating activities | 9.5 | -1.8 | -0.5 | 5.0 | 3.7 | -4.1 | 5.4 | 11.5 |
| Cash from operations | 22.0 | 22.8 | 21.0 | 30.8 | 27.6 | 23.9 | 29.8 | 40.9 |
| |
| Capital expenditures [+] | -1.9 | -1.4 | -2.0 | -1.4 | -4.7 | 0.0 | -1.4 | -1.4 |
| Purchases of property and equipment | -1.9 | -1.4 | -2.0 | -1.4 | -4.7 | 0.0 | -1.4 | -1.4 |
| Sales of property and equipment | 0.0 | 0.1 | 0.0 | 0.1 | 0.1 | 0.0 | 0.0 | |
| Sales of short-term investments, net [+] | 99.4 | 35.4 | 165.3 | 63.6 | 30.4 | -44.9 | 6.3 | -65.7 |
| Purchases of short-term investments | -17.8 | -0.3 | 0.0 | -5.7 | -24.5 | -124.7 | -69.8 | -289.3 |
| Sales of short-term investments | 117.2 | 35.6 | 165.4 | 69.3 | 54.9 | 79.8 | 76.1 | 223.6 |
| Other cash from investing | -86.1 | -5.0 | -56.3 | -38.3 | -117.4 | -3.0 | -0.9 | -36.3 |
| Cash from investing | 11.4 | 29.1 | 107.1 | 24.0 | -91.7 | -47.9 | 4.1 | -103.4 |
| |
| Cash dividends paid | -8.7 | -8.7 | -8.7 | -8.2 | -8.3 | -8.3 | -8.4 | -8.0 |
| Repurchase of common stock, net | -6.4 | | | -1.3 | -3.8 | -10.4 | -2.6 | -13.2 |
| Option exercises | 0.0 | -0.1 | -0.5 | 0.0 | | 2.9 | -0.1 | -0.2 |
| Other cash from financing | -7.3 | -50.5 | -145.7 | -22.1 | -18.6 | 157.6 | -293.4 | 125.9 |
| Cash from financing | -22.4 | -59.1 | -153.9 | -31.6 | -30.6 | 135.9 | -304.3 | 105.0 |
| |
| Free cash flow | 20.1 | 21.4 | 19.0 | 29.4 | 22.9 | 23.9 | 28.4 | 39.5 |
| Per share (diluted) | $1.40 | $1.48 | $1.32 | $2.05 | $1.59 | $1.65 | $1.94 | $2.71 |
| |
| Cash paid for interest | 19.6 | 14.9 | 9.8 | 5.6 | 2.8 | 2.8 | 1.0 | 5.6 |
| Cash paid for income taxes | 6.8 | 1.2 | 6.4 | 6.7 | 9.5 | 1.4 | 5.2 | 4.0 |