Financing Receivable, Modifications, Specific Reserves Allocated to Troubled Debt Restructuring

No definition available.

Name:	thff_FinancingReceivableModificationsSpecificReservesAllocatedtoTroubledDebtRestructuring
Namespace Prefix:	thff_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the minimum outstanding balance of loans to be individually reviewed and classified as to credit risk. Homogeneous loans (at all levels of outstanding balances) are not reviewed individually, but rather as part of a group.

+ References

No definition available.

+ Details

Name:	thff_LoansAndLeasesReceivableMinimumOutstandingBalanceToBeIndividuallyEvaluated
Namespace Prefix:	thff_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Provision charged for the period based on estimated losses to be realized from loan and lease transactions, based on decreases in the loss sharing Federal Deposit Insurance Corporation (FDIC) indemnification asset.

+ References

No definition available.

+ Details

Name:	thff_ProvisionForLoanAndLeaseLossesRelatedToFDICIndemnificationAssetChanges
Namespace Prefix:	thff_
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

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

- Definition

Recorded investment in financing receivables that are 90 days or more past due and still accruing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 7

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5111-111524

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

+ Details

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

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953550-111524

+ Details

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

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_NonperformingFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Allowance for Loan Losses (Details Textual) - USD ($)	3 Months Ended	6 Months Ended
Allowance for Loan Losses (Details Textual) - USD ($)	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2015	Dec. 31, 2014
Allowance for loan losses
Financing Receivable, Modifications, Specific Reserves Allocated to Troubled Debt Restructuring	$ 1,200,000	$ 1,200,000	$ 47,000
Increase in provision for decrease in FDIC indemnification asset	$ 464,000	$ 699,000
Fair value			16,024,000	$ 14,606,000
Allowance for Loan Losses Allocated			1,332,000	1,911,000
Minimum outstanding balance of non-homogeneous loans to be individually evaluated as to credit risk			100,000
Commercial & Industrial
Allowance for loan losses
Fair value			1,515,000	4,818,000
Allowance for Loan Losses Allocated			294,000	1,056,000
Farmland
Allowance for loan losses
Fair value			0	0
Allowance for Loan Losses Allocated			0	0
Covered Loans
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing				37,000
Nonaccrual			271,000	274,000
Non Farm, Non Residential
Allowance for loan losses
Fair value			1,431,000	5,901,000
Allowance for Loan Losses Allocated			919,000	753,000
Agriculture
Allowance for loan losses
Fair value			0
Allowance for Loan Losses Allocated			0	0
All Other Commercial
Allowance for loan losses
Fair value			460,000	725,000
Allowance for Loan Losses Allocated			92,000	102,000
First Liens
Allowance for loan losses
Fair value			199,000	33,000
Allowance for Loan Losses Allocated			27,000	0
Home Equity
Allowance for loan losses
Fair value			0	0
Allowance for Loan Losses Allocated			0	0
Junior Liens
Allowance for loan losses
Fair value			0	0
Allowance for Loan Losses Allocated			0	0
Multifamily
Allowance for loan losses
Fair value			0	0
Allowance for Loan Losses Allocated			0	0
All Other Residential
Allowance for loan losses
Fair value			0	0
Allowance for Loan Losses Allocated			0	0
Motor Vehicle
Allowance for loan losses
Fair value			0	0
Allowance for Loan Losses Allocated			0	0
All Other Consumer
Allowance for loan losses
Fair value			0	0
Allowance for Loan Losses Allocated			0	0
Nonperforming Financing Receivable [Member]
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			756,000	873,000
Nonaccrual			16,553,000	15,034,000
Nonperforming Financing Receivable [Member] \| Commercial & Industrial
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			0	0
Nonaccrual			4,002,000	3,720,000
Nonperforming Financing Receivable [Member] \| Farmland
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			0	0
Nonaccrual			228,000	79,000
Nonperforming Financing Receivable [Member] \| Non Farm, Non Residential
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			0	0
Nonaccrual			3,419,000	3,388,000
Nonperforming Financing Receivable [Member] \| Agriculture
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			0	0
Nonaccrual			537,000	767,000
Nonperforming Financing Receivable [Member] \| All Other Commercial
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			0	0
Nonaccrual			2,334,000	1,258,000
Nonperforming Financing Receivable [Member] \| First Liens
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			626,000	603,000
Nonaccrual			4,275,000	3,861,000
Nonperforming Financing Receivable [Member] \| Home Equity
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			24,000	88,000
Nonaccrual			306,000	404,000
Nonperforming Financing Receivable [Member] \| Junior Liens
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			63,000	12,000
Nonaccrual			157,000	275,000
Nonperforming Financing Receivable [Member] \| Multifamily
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			0	0
Nonaccrual			0	0
Nonperforming Financing Receivable [Member] \| All Other Residential
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			0	5,000
Nonaccrual			99,000	111,000
Nonperforming Financing Receivable [Member] \| Motor Vehicle
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			38,000	162,000
Nonaccrual			137,000	210,000
Nonperforming Financing Receivable [Member] \| All Other Consumer
Allowance for loan losses
Loans Past Due Over 90 Day Still Accruing			5,000	3,000
Nonaccrual			$ 1,059,000	$ 961,000