Retirement Plan And Other Post-Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost		$ 1,023	$ 1,049
Interest Cost		9,223	10,890
Expected Return on Plan Assets		(14,647)	(17,086)
Amortization of Prior Service Cost (Credit)		76	91
Amortization of (Gains) Losses		1,620	(335)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	(165)	4,057
Net Periodic Benefit Cost (Income)		(2,870)	(1,334)
Other Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service Cost		130	109
Interest Cost		3,625	3,890
Expected Return on Plan Assets		(6,536)	(6,660)
Amortization of Prior Service Cost (Credit)		(107)	(107)
Amortization of (Gains) Losses		9	(567)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	(727)	2,238
Net Periodic Benefit Cost (Income)		$ (3,606)	$ (1,097)

[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.