Commitments and Contingencies - Summary of the Company's Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans repurchased during period	$ 3,300	$ 3,300
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments representing credit risk	2,138,138	2,229,678
Letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments representing credit risk	$ 65,707	$ 68,983

Cash Flows between a transferor and a transferee attributable to purchases of previously transferred financial assets (or its underlying collateral) related to a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(3)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=d3e107207-111719

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- Definition

The fair value of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.

+ References

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

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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.

+ References

No definition available.

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