Loan Quality And Allowance For Credit Losses (Schedule Of Nonaccrual Loans And Loans Past Due Over 90 Days And Still On Accrual By Class Of Loans) (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2025	Dec. 31, 2024
Financing Receivable, Impaired [Line Items]
Nonaccrual, without ACL	$ 3,406	$ 266
Nonaccrual, with ACL	7,266
Loans past due 90 days or more and still accruing	12	2
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Loans past due 90 days or more and still accruing	7
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual, without ACL	3,406	266
Nonaccrual, with ACL	7,266
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Loans past due 90 days or more and still accruing	5	$ 2
First Liens [Member] \| Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Loans past due 90 days or more and still accruing	$ 7

Amount of financing receivable on nonaccrual status with allowance for credit loss.

No definition available.

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Namespace Prefix:	fraf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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.

+ Details

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

- Definition

Amortized cost of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- Definition

Amortized cost of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-80

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
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- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fraf_FirstLiensMember
Namespace Prefix:
Data Type:	na
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Period Type: