Income Taxes - FIN 48 Analysis (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	$ 0.1
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.0
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance beginning of year	0.1	$ 0.1	$ 0.1
Gross increases for tax positions related to prior years		0.0	0.0
Balance end of year	$ 0.0	$ 0.1	$ 0.1

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 10B
-URI http://asc.fasb.org/extlink&oid=84176650&loc=SL37586934-109318

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-Publisher FASB
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-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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