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RETIREMENT PLANS: (Details Textual) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 100.00% | 100.00% |
Employer contributions | $ 2,358 | $ 4,749 |
Cash contributions to ESOP | (1,402) | (1,471) | $ (1,251)
Cash contributions to ESOP for employees no longer participating in plan | 1,100 | 1,200 | 926
Pension plans with accumulated benefit obligations in excess of plan assets, aggregate accumulated benefit obligation | 102,400 | 105,200 |
Pension and other postretirement defined benefit plans, liabilities | 8,800 | 8,400 |
Accumulated other comprehensive income (loss) | (2,426) | 9,764 | (7,501)
First Financial Corporation Common Stock [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan assets equity securities | $ 18,100 | $ 16,500 |
Percentage of plan assets (percent) | 21.00% | 20.00% |
Equity Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 63.00% | 63.00% |
Debt securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 32.00% | 31.00% |
Other securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 5.00% | 6.00% |
Pension Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contributions | $ 2,050 | $ 4,440 | 1,770
Expected contributions to pension plan in 2014 | $ 250 |  |
Employee Stock Ownership Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 100.00% | 100.00% |
Cash contributions to ESOP | $ (703) |  |
Employee Stock Ownership Plan | First Financial Corporation Common Stock [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan assets equity securities | $ 7,200 | $ 5,500 |
Employee Stock Ownership Plan | Equity Securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 98.00% | 99.00% |
Employee Stock Ownership Plan | Debt securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 0.00% | 0.00% |
Employee Stock Ownership Plan | Other securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan Percentage Of Plan Assets | 2.00% | 1.00% |
Supplemental Employee Retirement Plans, Defined Benefit |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Pension expense | $ 748 | $ 539 | 339
Accumulated other comprehensive income (loss), after tax | 3,200 | 3,600 |
Accumulated other comprehensive income (loss) | (212) | (266) |
Postretirement Health Coverage [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Expected contributions to pension plan in 2014 | 248 |  |
Pension expense | 259 | 305 |
Amortization of transition obligations (assets) | $ 0 | $ 0 | $ (16)

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- Definition Assets, equity stocks, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. + References No definition available. + Details
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- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(30)(a)(4)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e637-108580 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(23)(a)(3)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669686-108580 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (h)(2) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (g)(2)(ii) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e681-108580 + Details
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