Short-term Debt - Narrative (Details) - USD ($)	Jun. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Short-term debt	$ 24,600,000	$ 24,600,000
Interest Bearing Loan
Debt Instrument [Line Items]
Short-term debt	23,500,000
Commercial Paper
Debt Instrument [Line Items]
Short-term debt	$ 0	$ 0

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant