XML 63 R54.htm IDEA: XBRL DOCUMENT
v3.23.3

Accumulated Other Comprehensive Income - Unrealized gains (losses) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | $ (141,250) | $ (126,630) | $ (139,974) | $ (2,426)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | (34,788) | (40,745) | (36,064) | (164,949)
Ending balance | (176,038) | (167,375) | (176,038) | (167,375)
Unrealized gains and (Losses) on available- for-sale Securities |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | (130,466) | (109,159) | (128,896) | 15,674
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | (34,934) | (41,060) | (36,504) | (165,893)
Ending balance | (165,400) | (150,219) | (165,400) | (150,219)
Unrealized gains (losses) on securities available-for-sale without other than temporary impairment |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | (132,671) | (111,474) | (131,135) | 13,155
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | (34,997) | (41,078) | (36,533) | (165,707)
Ending balance | (167,668) | (152,552) | (167,668) | (152,552)
Unrealized gains (losses) on securities available-for-sale with other than temporary impairment |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | 2,205 | 2,315 | 2,239 | 2,519
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | 63 | 18 | 29 | (186)
Ending balance | 2,268 | 2,333 | 2,268 | 2,333
Retirement plans |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | (10,784) | (17,471) | (11,078) | (18,100)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | 146 | 315 | 440 | 944
Ending balance | $ (10,638) | $ (17,156) | $ (10,638) | $ (17,156)

X
- Definition Accumulated Other Comprehensive Income (Loss) [Roll Forward] + References No definition available. + Details
Name: | thff_AccumulatedOtherComprehensiveIncomeLossRollForward
Namespace Prefix: | thff_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after tax, of accumulated increase (decrease) in equity from transaction and other event and circumstance from nonowner source. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -Publisher FASB -URI https://asc.fasb.org//1943274/2147482790/220-10-45-14A Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482790/220-10-45-11 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Subparagraph (g)(2)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480016/944-40-65-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Subparagraph (h)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480016/944-40-65-2 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(30)(a)(4)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(23)(a)(3)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482790/220-10-45-14 + Details
Name: | us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount after tax of other comprehensive income (loss) attributable to parent entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 19 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481231/810-10-45-19 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 20 -SubTopic 10 -Topic 810 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481231/810-10-45-20 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (c)(3) -SubTopic 10 -Topic 810 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481203/810-10-50-1A Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A + Details
Name: | us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=thff_UnrealizedGainsLossesOnSecuritiesAvailableforsaleWithoutOtherThanTemporaryImpairmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=thff_UnrealizedGainsLossesOnSecuritiesAvailableforsaleWithOtherThanTemporaryImpairmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |