Retirement Plan And Other Post-Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost		$ 1,049	$ 1,297
Interest Cost		10,890	10,629
Expected Return on Plan Assets		(17,086)	(16,648)
Amortization of Prior Service Cost (Credit)		91	109
Amortization of (Gains) Losses		(335)	(1,920)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	4,057	5,378
Net Periodic Benefit Cost (Income)		(1,334)	(1,155)
Other Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service Cost		109	147
Interest Cost		3,890	3,912
Expected Return on Plan Assets		(6,660)	(6,403)
Amortization of Prior Service Cost (Credit)		(107)	(107)
Amortization of (Gains) Losses		(567)	(2,189)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	2,238	3,820
Net Periodic Benefit Cost (Income)		$ (1,097)	$ (820)

[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.