| 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 |
| Operating Activities | | | | | | | | |
| Net Income | 16.1 | 36.3 | 26.2 | 9.7 | 17.1 | 36.9 | 22.7 | 12.5 |
| |
| Adjustments to reconcile net income to net cash from operating activities: | | | | | | | | |
| Depreciation and amortization | 17.3 | 17.2 | 17.4 | 17.3 | 17.2 | 17.0 | 16.2 | 15.8 |
| Depreciation and accretion included in other costs | 2.9 | 2.8 | | | 3.0 | 2.7 | | |
| Deferred income taxes | 3.2 | 2.5 | 7.5 | 4.8 | 4.0 | 7.4 | 8.6 | 5.2 |
| Gain on sale of discontinued operations | | | | | | | | |
| Realized gain on commodity contracts and sale of assets | -0.7 | -0.3 | -0.3 | -0.3 | -2.7 | -4.3 | -2.8 | -0.9 |
| Unrealized (gain) loss on investments/commodity contracts | -1.1 | | | | 2.0 | | | |
| Employee benefits and compensation | 0.6 | 2.5 | 1.4 | 0.9 | 1.1 | 2.0 | 1.8 | 1.1 |
| Share-based compensation | 0.6 | 2.5 | 1.4 | 0.9 | 1.1 | 2.0 | 1.8 | 1.1 |
| Changes in assets and liabilities: | | | | | | | | |
| Accounts receivable and accrued revenue | 25.2 | 5.6 | -41.9 | 5.9 | 17.2 | 7.5 | -24.1 | -1.2 |
| Propane inventory, storage gas and other inventory | -0.3 | 5.4 | -4.5 | -3.6 | -3.8 | 4.0 | -5.1 | -3.3 |
| Regulatory assets/liabilities, net | 4.2 | 24.6 | -11.2 | -21.0 | -12.2 | 5.8 | -11.9 | -14.3 |
| Prepaid expenses and other current assets | -1.0 | 4.0 | 3.6 | -4.8 | 3.7 | 6.6 | 5.3 | -9.6 |
| Accounts payable and other accrued liabilities | 6.3 | -29.6 | 7.7 | 2.3 | 10.8 | -19.3 | -8.1 | 14.4 |
| Income taxes receivable/payable | -8.8 | 10.1 | 16.3 | -6.5 | -1.0 | 6.1 | -4.8 | -4.3 |
| Customer deposits and refunds | 1.8 | -0.5 | -0.7 | 3.3 | 1.1 | -3.1 | 0.7 | 1.8 |
| Accrued compensation | 3.4 | -8.4 | 4.2 | 0.8 | 0.1 | -6.4 | 1.9 | 2.7 |
| Other assets and liabilities, net | 1.2 | 1.5 | 1.8 | 1.3 | -2.3 | -0.8 | 2.0 | -1.3 |
| Net cash provided by operating activities | 67.3 | 81.7 | 22.9 | 12.2 | 54.7 | 69.1 | -2.3 | 18.6 |
| |
| Investing Activities | | | | | | | | |
| Property, plant and equipment expenditures | -47.8 | -42.4 | -30.2 | -32.9 | -35.2 | -29.9 | -38.7 | -43.6 |
| Proceeds from sale of assets | 1.5 | 0.5 | 0.3 | 0.2 | 3.1 | 0.2 | 0.3 | 0.2 |
| |
| Proceeds from the sale of discontinued operations | | | | | | | | |
| Environmental expenditures | 0.0 | 0.7 | -0.9 | 0.2 | 0.2 | 0.3 | -1.4 | 0.2 |
| Net cash used in investing activities | -46.3 | -42.7 | -39.3 | -33.0 | -34.2 | -29.9 | -74.9 | -43.5 |
| |
| Financing Activities | | | | | | | | |
| Common stock dividends | -9.5 | -9.5 | -9.3 | -9.3 | -8.3 | -8.3 | -8.3 | -8.2 |
| Issuance of stock under the Dividend Reinvestment Plan, net of offering fees | 0.0 | | | 0.2 | 1.0 | 3.2 | | 2.3 |
| Tax withholding payments related to net settled stock compensation | | -2.5 | | | | -2.8 | | |
| Change in cash overdrafts due to outstanding checks | -1.8 | -0.3 | 1.1 | 1.0 | -2.4 | 1.2 | -0.6 | 0.6 |
| Net repayments under line of credit agreements | 3.6 | -107.8 | 83.5 | 29.1 | -1.4 | -82.0 | 89.7 | 21.6 |
| Repayment of long-term debt | -12.1 | -2.0 | -5.5 | -2.0 | -10.3 | -0.2 | -3.7 | |
| Net cash used in financing activities | -19.9 | -42.2 | 20.2 | 19.0 | -21.5 | -39.0 | 76.3 | 25.9 |
| Net Increase (Decrease) in Cash and Cash Equivalents | 1.1 | -3.1 | | | -1.0 | 0.2 | | |
| Payments to Acquire Businesses, Gross | | | -9.8 | | -2.0 | | -36.4 | |