Stock-based Compensation - Schedule of Fair Value at the Date of Grant (Detail) - Fiscal 2017 (2017 - 2019) [Member]	6 Months Ended
Mar. 31, 2019 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum Shares	9,352
Target Shares	46,758
Maximum Shares	93,516

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.

No definition available.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration