Debt - Schedule of Long-term Debt Obligations (Parenthetical) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense	$ 11,073	$ 12,686
Other Noncurrent Assets \| Line of Credit
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense	$ 4,100	$ 4,900

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_UnamortizedDebtIssuanceExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant