Derivative Financial Instruments - Additional Information (Detail) - USD ($)	6 Months Ended
Mar. 31, 2021	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Short-term forward contracts, average maturities at inception (less than)	3 months
Foreign currency forward contracts
Derivative [Line Items]
Forward foreign currency contracts fair value	$ 0	$ 0

Fair value of the assets less the liabilities of a derivative or group of derivatives.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

Name:	us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant