Leases - ROU Assets and Lease Liabilities (Details) $ in Thousands	Sep. 30, 2022 USD ($) serviceCenter	Sep. 30, 2021 USD ($)
Assets
Finance leases	$ 50,118	$ 18,252
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Public Utilities, Property, Plant and Equipment, Net	Public Utilities, Property, Plant and Equipment, Net
Operating leases	$ 214,663	$ 222,446
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Deferred charges and other assets (See Note 9)	Deferred charges and other assets (See Note 9)
Total right-of-use assets	$ 264,781	$ 240,698
Current
Finance leases	$ 1,457	$ 452
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current maturities of long-term debt	Current maturities of long-term debt
Operating leases	$ 38,644	$ 37,688
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Noncurrent
Finance leases	$ 50,393	$ 18,287
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term debt	Long-term debt
Operating leases	$ 184,301	$ 194,745
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Deferred credits and other liabilities	Deferred credits and other liabilities
Total	$ 274,795	$ 251,172
Number of buildings leased | serviceCenter	2
Total future lease payments	$ 48,100