Loans Receivable - Summary of Troubled Debt Restructurings Granted (Detail) $ in Thousands	12 Months Ended
Sep. 30, 2017 USD ($) Contract	Sep. 30, 2016 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	11	17
Real Estate Loans [Member] \| Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	6	12
Pre-Modification Outstanding Recorded Investment	$ 1,154	$ 1,701
Post-Modification Outstanding Recorded Investment	$ 1,167	$ 1,701
Real Estate Loans [Member] \| Commercial Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	2	4
Pre-Modification Outstanding Recorded Investment	$ 1,208	$ 2,139
Post-Modification Outstanding Recorded Investment	$ 1,163	$ 2,139
Home Equity Loans and Lines of Credit [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract		1
Pre-Modification Outstanding Recorded Investment		$ 5
Post-Modification Outstanding Recorded Investment		$ 5
Auto Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	2
Pre-Modification Outstanding Recorded Investment	$ 37
Post-Modification Outstanding Recorded Investment	$ 37
Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	1
Pre-Modification Outstanding Recorded Investment	$ 22
Post-Modification Outstanding Recorded Investment	$ 22
Troubled Debt Restructurings [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	11	17
Pre-Modification Outstanding Recorded Investment	$ 2,421	$ 3,845
Post-Modification Outstanding Recorded Investment	$ 2,389	$ 3,845

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

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Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

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