| In millions, except per share items | Mar-31-23 | Dec-31-22 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 | Jun-30-21 |
| | 8-K | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K |
| Operating activities: | | | | | | | | |
| Net income | | 36.4 | 36.1 | 49.7 | 54.8 | 31.0 | 27.9 | 35.0 |
| Adjustments to reconcile net income to net cash from operating activities: | | | | | | | | |
| Non-cash compensation expense | | 2.0 | 1.6 | 1.8 | 1.7 | 1.6 | 1.3 | 1.5 |
| Non-cash compensation to directors | | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.2 | 0.2 |
| Depreciation | | 5.4 | 5.3 | 5.0 | 4.8 | 4.6 | 4.9 | 4.4 |
| Amortization | | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.9 | 2.1 |
| Deferred income taxes | | 1.4 | 1.1 | -1.0 | 2.1 | 3.0 | 0.7 | 1.0 |
| Other items, net | | 0.2 | 0.6 | 0.4 | 0.6 | -0.2 | 0.5 | 0.6 |
| Change in operating assets and liabilities: | | | | | | | | |
| Trade receivables | | -9.0 | 5.2 | -2.5 | -27.3 | 19.4 | 8.6 | -12.9 |
| Inventories | | -2.9 | -25.7 | 6.9 | -9.4 | -13.4 | -22.2 | -1.1 |
| Prepaid expenses and other assets | | -0.5 | -3.8 | 2.5 | 3.0 | -0.8 | -4.7 | 1.6 |
| Accounts payable | | -11.3 | 7.2 | -17.3 | 19.8 | -8.3 | 5.5 | 3.6 |
| Income taxes payable | | -8.3 | 8.8 | -0.9 | 3.0 | -8.3 | 5.4 | -1.3 |
| Accrued expenses | | 4.3 | -6.2 | 3.7 | 6.6 | 6.1 | -5.8 | 1.4 |
| Other liabilities | | -0.5 | -0.6 | -0.6 | -0.6 | -2.5 | -0.5 | -4.6 |
| Net cash provided by operating activities | | 19.1 | 31.7 | 45.8 | 61.1 | 34.3 | 23.7 | 30.9 |
| |
| Investing activities: | | | | | | | | |
| Purchases of property, plant and equipment | | -10.0 | -12.4 | -15.0 | -13.8 | -12.3 | -13.9 | -11.6 |
| Net cash used in investing activities | | -10.0 | -12.4 | -15.0 | -20.4 | -12.3 | -13.9 | -11.6 |
| |
| Financing activities: | | | | | | | | |
| Proceeds from revolving credit facility | | 20.0 | 121.7 | | | | | |
| Payments on revolving credit facility | | -20.0 | -147.0 | -56.3 | | | -20.0 | 8.2 |
| Payment of deferred financing costs | | | -1.4 | | | | | |
| Proceeds received from exercise of stock options | | | | 2.3 | | 1.0 | | |
| Cash paid for withholding taxes on vested restricted stock | | -2.0 | -0.9 | | 0.0 | -1.5 | -0.5 | |
| Distributions to LLC Unit holders | | -0.7 | -1.0 | -1.0 | -0.5 | -0.6 | -0.7 | -0.7 |
| Repurchase and retirement of common stock | | | -7.9 | -4.4 | -25.0 | -5.2 | | |
| Net cash used in financing activities | | -2.7 | -59.6 | -3.4 | -28.8 | -6.6 | -21.5 | -21.0 |
| Effect of exchange rate changes on cash | | 0.3 | -0.4 | -0.6 | 0.2 | 0.0 | -0.3 | 0.1 |
| Changes in cash | | 6.8 | -40.7 | 26.8 | 12.1 | 15.3 | -12.0 | -1.5 |
| |
| Supplemental cash flow information: | | | | | | | | |
| Cash paid for interest | | 0.2 | 1.1 | 0.8 | 0.5 | 0.5 | 0.5 | 0.6 |
| Cash paid for income taxes | | 19.4 | 0.8 | 15.1 | 10.4 | 14.6 | 2.0 | 10.9 |