Retirement Plan And Other Post-Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost		$ 1,049	$ 1,297	$ 3,148	$ 3,891
Interest Cost		10,890	10,629	32,668	31,887
Expected Return on Plan Assets		(17,086)	(16,648)	(51,257)	(49,945)
Amortization of Prior Service Cost (Credit)		91	109	271	327
Amortization of (Gains) Losses		(335)	(1,920)	(1,004)	(5,760)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	4,057	5,378	12,173	16,134
Net Periodic Benefit Cost (Income)		(1,334)	(1,155)	(4,001)	(3,466)
Other Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service Cost		109	147	326	440
Interest Cost		3,890	3,912	11,671	11,736
Expected Return on Plan Assets		(6,660)	(6,403)	(19,981)	(19,210)
Amortization of Prior Service Cost (Credit)		(107)	(107)	(322)	(321)
Amortization of (Gains) Losses		(567)	(2,189)	(1,700)	(6,566)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	2,248	3,829	6,256	11,143
Net Periodic Benefit Cost (Income)		$ (1,087)	$ (811)	$ (3,750)	$ (2,778)

[1] The Company’s policy is to record retirement plan and other post-retirement benefit costs in the Utility segment on a volumetric basis to reflect the fact that the Utility segment experiences higher throughput of natural gas in the winter months and lower throughput of natural gas in the summer months.