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Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019
Income Tax Disclosure [Line Items]
Provision/(benefit) for income taxes	$ (4.9)	$ (0.3)
Gross unrecognized tax benefits	20.1		$ 18.9
Gross unrecognized tax benefits increased (decreased) during the year	1.2
Interest and penalties accrued related to unrecognized tax benefits	1.7
Increase (decrease) in interest and penalties accrued related to unrecognized tax benefits			$ (0.2)
Maximum [Member]
Income Tax Disclosure [Line Items]
Estimated increase in unrecognized tax benefit in next twelve months	$ 2.5

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- Definition

Income tax disclosure.

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Increase (Decrease) in unrecognized tax benefit income tax penalties and interest accrued.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
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Amount of increase reasonably possible in the next twelve months for the unrecognized tax benefit.

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Amount of unrecognized tax benefits.

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Amount accrued 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.

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Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns.

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