Fair Value - Additional Information (Detail) $ in Thousands	Sep. 30, 2020 USD ($) Loan	Sep. 30, 2019 USD ($) Loan
Fair Value Disclosures [Abstract]
Number of impaired loans \| Loan	111	138
Impaired loans, carrying value	$ 17,200	$ 8,400
Impaired loans, valuation allowance	221	248
Impaired loans, net fair value	17,000	8,100
Impaired loans, fair value	$ 17,200	$ 8,400

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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