XML 57 R47.htm IDEA: XBRL DOCUMENT
v3.25.1

Qualified Affordable Housing Project Investments (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Qualified Affordable Housing Project Investments [Line Items] |  |  |
Investment for qualified housing projects balance | $ 26,400 |  | $ 27,200
Unfunded commitments related to the investments in qualified affordable housing projects | 15,000 |  | $ 17,700
Amortization expense |  | $ 195 |
Investment Program, Proportional Amortization Method, Applied, Amortization Expense, Statement of Income or Comprehensive Income [Extensible Enumeration] |  | Other Noninterest Expense |
Recognized tax credits and other benefits form its investment | 914 | $ 363 |
Other non interest expense |  |  |
Qualified Affordable Housing Project Investments [Line Items] |  |  |
Amortization expense | 16 |  |
Income tax expense |  |  |
Qualified Affordable Housing Project Investments [Line Items] |  |  |
Amortization expense | $ 720 |  |

X
- Definition Disclosure of information about qualified affordable housing project investments. + References No definition available. + Details
Name: | thff_QualifiedAffordableHousingProjectInvestmentsLineItems
Namespace Prefix: | thff_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before amortization expense, of income tax credit and other tax benefit generated by investment under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under tax credit program not meeting condition for accounting under proportional amortization method. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 323 -SubTopic 740 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/323-740-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A + Details
Name: | us-gaap_AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment that generates income tax credit and other income tax benefit under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under program not meeting condition for accounting under proportional amortization method. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A + Details
Name: | us-gaap_AmortizationMethodQualifiedAffordableHousingProjectInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of amortization expense for investment that generates income tax credit and other income tax benefit under tax credit program accounted for using proportional amortization method. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A + Details
Name: | us-gaap_AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Indicates line item in statement of income or comprehensive income that includes amortization expense for investment that generates income tax credit and other income tax benefit under tax credit program accounted for using proportional amortization method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A + Details
Name: | us-gaap_InvestmentProgramProportionalAmortizationMethodAppliedIncomeTaxCreditAndOtherTaxBenefitAmortizationStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration
Namespace Prefix: | us-gaap_
Data Type: | enum2:enumerationSetItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of commitment and contingent commitment, including amount of delayed equity contribution, for investment that generates income tax credit and other income tax benefit under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, commitment and contingent commitment related to investment under tax credit program not meeting condition for accounting under proportional amortization method. + References Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 740 -SubTopic 323 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478156/740-323-50-2 + Details
Name: | us-gaap_QualifiedAffordableHousingProjectInvestmentsCommitment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=thff_OtherNonInterestExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=thff_IncomeTaxExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |