v3.25.1

Mortgage Banking Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Mortgage Banking Income (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Mortgage Banking Income
Origination and sale of mortgage loans	$ 44	$ (991)	$ 59	$ (1,202)
Mortgage brokerage income	10	1	27	31
Net change in fair value of loans held for sale and interest rate lock commitments		993		(304)
Realized and unrealized gains (losses) from Forward sales commitments				354
Capitalized residential mortgage loan servicing rights				509
Net change in fair value of residential mortgage loan servicing rights		(6)		(809)
Provisions for loan repurchases and indemnifications	50	(37)	93	19
Net loan servicing income		93	3	1,544
Total mortgage banking income	$ 104	$ 53	$ 182	$ 142

The amount of capitalized residential mortgage loan servicing rights.

+ References

No definition available.

+ Details

Name:	fsfg_CapitalizedResidentialMortgageLoanServicingRights
Namespace Prefix:	fsfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of loan servicing income.

+ References

No definition available.

+ Details

Name:	fsfg_LoanServicingIncome
Namespace Prefix:	fsfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of net change in fair value of loans held for sale and interest rate lock commitments.

+ References

No definition available.

+ Details

Name:	fsfg_NetChangeInFairValueOfLoansHeldForSaleAndInterestRateLockCommitments
Namespace Prefix:	fsfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of net change in fair value of residential mortgage loan servicing rights.

+ References

No definition available.

+ Details

Name:	fsfg_NetChangeInFairValueOfResidentialMortgageLoanServicingRights
Namespace Prefix:	fsfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of income from origination and sale of mortgage loans.

+ References

No definition available.

+ Details

Name:	fsfg_OriginationAndSaleOfMortgageLoans
Namespace Prefix:	fsfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of provisions for loan repurchases and indemnifications.

+ References

No definition available.

+ Details

Name:	fsfg_ProvisionsForLoanRepurchasesAndIndemnifications
Namespace Prefix:	fsfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of realized and unrealized gains (losses) from forward sales commitments.

+ References

No definition available.

+ Details

Name:	fsfg_RealizedAndUnrealizedGainsLossesFromForwardSalesCommitments
Namespace Prefix:	fsfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Income from mortgage banking activities (fees and commissions) and servicing real estate mortgages, credit cards, and other financial assets held by others net of any related impairment of capitalized service costs. Also includes any premiums received in lieu of regular servicing fees on such loans only as earned over the life of the loans.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph b
-Subparagraph (1)
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph b
-Subparagraph (1)(Instruction 3)
-Publisher SEC

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of fees and commissions from banking, advisory, brokerage, and securities underwriting activities. Activities include, but are not limited to, underwriting securities, private placements of securities, investment advisory and management services, merger and acquisition services, sale and servicing of mutual funds, and other related consulting fees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(13)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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

First Savings Financial Group, Inc. 10-Q