Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Restructuring Expenses - Additional Information (Details)	12 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($) position
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0	$ 0	$ 4,500,000
Number of positions reduced \| position			79
Facilities charges
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 1,700,000
Employee separation
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 2,800,000