v3.25.2
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, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Retirement Plan        
Defined Benefit Plan Disclosure [Line Items]        
Service Cost $ 1,023 $ 1,049 $ 3,069 $ 3,148
Interest Cost 9,223 10,890 27,669 32,668
Expected Return on Plan Assets (14,647) (17,086) (43,940) (51,257)
Amortization of Prior Service Cost (Credit) 76 91 227 271
Amortization of (Gains) Losses 1,620 (335) 4,860 (1,004)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments) [1] 85 4,057 (3,026) 12,173
Net Periodic Benefit Cost (Income) (2,620) (1,334) (11,141) (4,001)
Other Post-Retirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Service Cost 130 109 389 326
Interest Cost 3,625 3,890 10,876 11,671
Expected Return on Plan Assets (6,536) (6,660) (19,608) (19,981)
Amortization of Prior Service Cost (Credit) (107) (107) (322) (322)
Amortization of (Gains) Losses 9 (567) 28 (1,700)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments) [1] (447) 2,248 (5,333) 6,256
Net Periodic Benefit Cost (Income) $ (3,326) $ (1,087) $ (13,970) $ (3,750)
[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.