-- None. No documentation exists for this element. --

No definition available.

Name:	thff_FinancingReceivableAbstract
Namespace Prefix:	thff_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Recorded Investment in financing receivables.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

+ Details

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

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

+ Details

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

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

+ Details

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

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)(1)(ii)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section L

-Subsection 1

+ Details

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

- Definition

Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_ReceivablesAcquiredWithDeterioratedCreditQualityAxis=us-gaap_ReceivablesAcquiredWithDeterioratedCreditQualityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Allowance for Loan Losses (Details 1) - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Ending Balance Attributable to Loans
Individually evaluated for impairment	$ 1,228		$ 1,911
Collectively evaluated for impairment	18,506		16,648
Ending Balance	19,925	$ 19,861	18,839	$ 17,507	$ 18,255	$ 20,068
Loans
Individually evaluated for impairment	10,582		14,606
Collectively evaluated for impairment	1,756,626		1,767,701
Total	1,772,988		1,788,825
Commercial Portfolio Segment [Member]
Ending Balance Attributable to Loans
Individually evaluated for impairment	996		1,911
Collectively evaluated for impairment	10,902		8,733
Ending Balance	12,089	10,931	10,915	10,180	10,850	12,450
Loans
Individually evaluated for impairment	9,648		14,573
Collectively evaluated for impairment	1,032,992		1,030,949
Total	1,046,834		1,050,409
Residential Portfolio Segment [Member]
Ending Balance Attributable to Loans
Individually evaluated for impairment	232		0
Collectively evaluated for impairment	1,662		1,365
Ending Balance	1,894	1,760	1,374	1,327	1,374	1,585
Loans
Individually evaluated for impairment	934		33
Collectively evaluated for impairment	450,198		468,872
Total	452,718		470,536
Consumer Portfolio Segment [Member]
Ending Balance Attributable to Loans
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	4,948		4,370
Ending Balance	4,948	4,678	4,370	3,916	3,769	3,650
Loans
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	273,436		267,880
Total	273,436		267,880
Unallocated
Ending Balance Attributable to Loans
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	994		2,180
Ending Balance	994	$ 2,492	2,180	$ 2,084	$ 2,262	$ 2,383
Receivables Acquired with Deteriorated Credit Quality [Member]
Ending Balance Attributable to Loans
Financing Receivable, Allowance for Credit Losses	191		280
Loans
Financing Receivable, Net	5,780		6,518
Receivables Acquired with Deteriorated Credit Quality [Member] \| Commercial Portfolio Segment [Member]
Ending Balance Attributable to Loans
Financing Receivable, Allowance for Credit Losses	191		271
Loans
Financing Receivable, Net	4,194		4,887
Receivables Acquired with Deteriorated Credit Quality [Member] \| Residential Portfolio Segment [Member]
Ending Balance Attributable to Loans
Financing Receivable, Allowance for Credit Losses	0		9
Loans
Financing Receivable, Net	1,586		1,631
Receivables Acquired with Deteriorated Credit Quality [Member] \| Consumer Portfolio Segment [Member]
Ending Balance Attributable to Loans
Financing Receivable, Allowance for Credit Losses	0		0
Loans
Financing Receivable, Net	0		0
Receivables Acquired with Deteriorated Credit Quality [Member] \| Unallocated
Ending Balance Attributable to Loans
Financing Receivable, Allowance for Credit Losses	$ 0		$ 0