CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES
Net income	$ 122,490	$ 131,319
Adjustments to reconcile net income to cash flows from operating activities
Unrealized loss on derivative instruments	2,996	6,368
Gain on sale of assets	0	(54,859)
Depreciation and amortization	49,576	45,329
Allowance for equity used during construction	(2,757)	(1,086)
Allowance for doubtful accounts	(659)	194
Non cash lease expense	1,102	1,071
Deferred income taxes	28,614	20,522
Equivalent value of ITCs recognized on equipment financing	(5,357)	(4,352)
Manufactured gas plant remediation costs	(972)	(1,126)
Equity in earnings, net of distributions received from equity investees	(360)	0
Cost of removal - asset retirement obligations	(511)	(432)
Contributions to postemployment benefit plans	(265)	(227)
Changes in:
Components of working capital	(208,844)	(186,074)
Other noncurrent assets and liabilities	41,675	34,398
Cash flows from (used in) operating activities	26,728	(8,955)
Expenditures for:
Cost of removal	(10,789)	(10,775)
Distribution from equity investees in excess of equity in earnings	0	99
Proceeds from sale of assets	0	132,500
Cash flows used in investing activities	(179,536)	(19,271)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from long-term debt	0	100,000
Payments of long-term debt	(6,081)	(107,676)
Proceeds from short-term debt, net	173,400	45,200
Proceeds from sale leaseback transactions - solar	23,240	12,567
Proceeds from sale leaseback transactions - natural gas meters	15,016	11,714
Payments of common stock dividends	(47,719)	(44,752)
Proceeds from waiver discount issuance of common stock	0	19,910
Proceeds from issuance of common stock - DRP	3,778	3,793
Tax withholding payments related to net settled stock compensation	(6,882)	(11,579)
Cash flows from financing activities	154,752	29,177
Change in cash, cash equivalents and restricted cash	1,944	951
Cash, cash equivalents and restricted cash at beginning of period	1,649	1,612
Cash, cash equivalents and restricted cash at end of period	3,593	2,563
CHANGES IN COMPONENTS OF WORKING CAPITAL
Receivables	(279,242)	(203,094)
Inventories	22,921	5,247
Recovery of natural gas costs	33,468	(375)
Natural gas purchases payable	32,495	30,998
Natural gas purchases payable - related parties	(1)	6
Deferred revenue, current	(1,232)	650
Accounts payable and other	(48,932)	(45,967)
Prepaid expenses	(9,155)	(7,421)
Prepaid and accrued taxes	35,406	37,009
Restricted broker margin accounts	(2,350)	(2,849)
Customers' credit balances and deposits	8,948	3,992
Other current assets and liabilities	(1,170)	(4,270)
Total	(208,844)	(186,074)
Cash paid for:
Interest (net of amounts capitalized)	35,799	34,843
Income taxes	147	863
Accrued capital expenditures	42,096	19,309
Utility plant
Expenditures for:
Payments to acquire PP&E	(96,129)	(99,143)
Solar equipment
Expenditures for:
Payments to acquire PP&E	(59,701)	(33,476)
Storage and Transportation and other
Expenditures for:
Payments to acquire PP&E	$ (12,917)	$ (8,476)