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Stock-based Compensation Plans (Schedule of Share-based Compensation, Effect on Statement of Operations) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Decrease in operating income	$ 9.9	$ 11.0	$ 7.2
Effect on net income or loss	$ (7.6)	$ (8.2)	$ (5.5)
Effect on earnings or loss per basic share	$ (0.05)	$ (0.05)	$ (0.03)
Effect on earnings or loss per diluted share	$ (0.05)	$ (0.05)	$ (0.03)

X

- Definition

Share-based Compensation, Increase (Decrease) in Earnings Per Share, Basic

+ References

No definition available.

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- Definition

Share-based Compensation, Increase (Decrease) in Earnings Per Share, Diluted

+ References

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X

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Amount, after tax, of expense for award under share-based payment arrangement.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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