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Leases, Codification Topic 842 (Policies) | 3 Months Ended
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Mar. 31, 2026
Leases [Abstract] |
Lessee, Leases [Policy Text Block] | A lease is defined as a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment for a period of time in exchange for consideration. For contracts where First Financial is a lessee, the recipient of the right to control, substantially all of those agreements are for real estate property for branches, ATM locations and office space.

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- Definition Disclosure of accounting policy for leasing arrangement entered into by lessee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-1 + Details
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