CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
OPERATING REVENUES
Utility	$ 1,011,284	$ 1,127,417	$ 731,459
Nonutility	951,710	1,778,562	1,425,154
Total operating revenues	1,962,994	2,905,979	2,156,613
Natural gas purchases:
Related parties	7,206	7,395	7,013
Operation and maintenance	373,568	361,866	366,905
Regulatory rider expenses	50,542	59,437	38,304
Depreciation and amortization	152,941	129,249	111,387
Total operating expenses	1,555,994	2,499,504	1,868,263
OPERATING INCOME	407,000	406,475	288,350
Other income, net	26,083	22,295	24,597
Interest expense, net of capitalized interest	123,014	85,830	78,559
INCOME BEFORE INCOME TAXES AND EQUITY IN EARNINGS OF AFFILIATES	310,069	342,940	234,388
Income tax provision	49,275	76,195	33,286
Equity in earnings (loss) of affiliates	3,930	8,177	(83,212)
NET INCOME	$ 264,724	$ 274,922	$ 117,890
EARNINGS PER COMMON SHARE
Basic (usd per share)	$ 2.73	$ 2.86	$ 1.23
Diluted (usd per share)	$ 2.71	$ 2.85	$ 1.22
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (in shares)	97,028	96,100	96,227
Diluted (in shares)	97,627	96,488	96,560
Regulated
Natural gas purchases:
Gas purchases - Utility and Nonutility	$ 416,158	$ 547,901	$ 247,734
Unregulated
Natural gas purchases:
Gas purchases - Utility and Nonutility	$ 555,579	$ 1,393,656	$ 1,096,920