SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Dec. 31, 2016
Basis of Presentation Policy	Basis of presentation. The Consolidated Financial Statements of First Financial Bancorp., a bank holding company, principally serving Ohio, Indiana and Kentucky, include the accounts and operations of First Financial and its wholly owned subsidiary, First Financial Bank. All significant intercompany transactions and accounts have been eliminated in consolidation. Certain reclassifications of prior years' amounts have been made to conform to current year presentation. Such reclassifications had no effect on net earnings.
Use of Estimates, Policy	Use of estimates. The preparation of Consolidated Financial Statements in conformity with GAAP requires management to make estimates, assumptions and judgments that affect the amounts reported in the Consolidated Financial Statements and accompanying Notes. Actual realized amounts could differ materially from those estimates.
Investment, Policy	Investment securities. First Financial classifies debt and equity securities into three categories: held-to-maturity, trading and available-for-sale. Management classifies investment securities into the appropriate category at the time of purchase and re-evaluates that classification as deemed appropriate. Investment securities are classified as held-to-maturity when First Financial has the positive intent and ability to hold the securities to maturity. Held-to-maturity securities are recorded at amortized cost. Investment securities classified as trading are held principally for resale in the near-term and are recorded at fair value. Fair value is determined using quoted market prices. Gains or losses on trading securities, both realized and unrealized, are reported in noninterest income. Investment securities not classified as either held-to-maturity or trading are classified as available-for-sale. Available-for-sale securities are recorded at fair value, with the unrealized gains and losses, net of tax, reported as a separate component of accumulated other comprehensive income (loss) in shareholders' equity. The amortized cost of investment securities classified as either held-to-maturity or available-for-sale is adjusted for amortization of premiums and accretion of discounts to maturity, or in the case of mortgage-backed securities, over the estimated life of the security. Such amortization and accretion are considered an adjustment to the yield on the security and included in interest income from investments. Interest and dividends are included in interest income from investment securities in the Consolidated Statements of Income. Realized gains and losses are based on the amortized cost of the security sold using the specific identification method. Available-for-sale and held-to-maturity securities are reviewed quarterly for potential impairment. In performing this review, management considers the length of time and extent to which the fair value of the security has been less than amortized cost, the financial condition and near-term prospects of the issuer and the ability and intent of First Financial to hold the security for a period sufficient to allow for any anticipated recovery in fair value. If the fair value of a security is less than the amortized cost and the impairment is determined to be other-than-temporary, the security is written down, establishing a new and reduced cost basis. The related charge is recorded in the Consolidated Statements of Income. Other investments. Other investments include holdings in FRB stock and FHLB stock, which are both carried at cost.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	Loans held for sale. Loans held for sale consists of residential real estate loans newly originated for the purpose of sale to third parties, and in certain circumstances, loans previously originated that have been specifically identified by management for sale based on predetermined criteria. Loans transferred to held for sale status are carried at the lower of cost or fair value. Any subsequent change in the carrying value of transferred loans, not to exceed original cost, is recorded in the Consolidated Statements of Income.
Commitments and Contingencies, Policy	Reserve for unfunded commitments. First Financial maintains a reserve that it considers sufficient to absorb probable losses incurred in standby letters of credit and outstanding loan commitments, which is included in Accrued interest and other liabilities on the Consolidated Balance Sheets. The determination of the adequacy of the reserve is based upon an evaluation of the unfunded credit facilities, including consideration of historical commitment utilization experience, credit risk rating and historical loss rates, consistent with the Company's ALLL methodology. Adjustments to the reserve for unfunded commitments are included in Other noninterest expense in the Consolidated Statements of Income. First Financial offers a variety of financial instruments with off-balance-sheet risk to its clients to assist them in meeting their requirement for liquidity and credit enhancement. These financial instruments include standby letters of credit and outstanding commitments to extend credit. GAAP does not require these financial instruments to be recorded in the Consolidated Financial Statements. First Financial utilizes the same credit policies in issuing commitments and conditional obligations as it does for credit instruments recorded on the Consolidated Balance Sheets. First Financial’s exposure to credit loss, in the event of nonperformance by the counterparty to the financial instrument for standby letters of credit and outstanding commitments to extend credit, is represented by the contractual amounts of those instruments. First Financial utilizes the ALLL methodology to maintain a reserve that it considers sufficient to absorb probable losses incurred in standby letters of credit and outstanding loan commitments and records the reserve within Accrued interest and other liabilities on the Consolidated Balance Sheets.
FDIC Indemnification Assets Policy	FDIC indemnification asset. The FDIC indemnification asset results from the loss sharing agreements entered into in conjunction with First Financial's FDIC-assisted transactions, and represents expected reimbursements from the FDIC for losses on covered assets. The FDIC indemnification asset is measured separately from the related assets covered by loss sharing agreements with the FDIC as it is not contractually embedded in those assets and is not transferable should First Financial choose to dispose of the covered assets. Pursuant to the terms of the loss sharing agreements, covered assets are subject to stated loss thresholds whereby the FDIC will reimburse First Financial for 80% of losses up to the stated loss thresholds, and 95% of losses in excess of the thresholds. The FDIC indemnification asset was recorded at its estimated fair value at the time of the FDIC-assisted transactions. Fair values were estimated using projected cash flows related to the loss sharing agreements based on the expected reimbursements for losses and the applicable loss sharing percentages. These cash flows were discounted to reflect the uncertainty of the timing of the loss sharing reimbursement from the FDIC. The accounting for the FDIC indemnification asset is closely related to the accounting for the underlying, indemnified assets as well as ongoing assessment of the collectibility of the indemnification asset. The primary activities impacting the FDIC indemnification asset are FDIC claims, amortization, FDIC loss sharing income and accelerated discount.
Property, Plant and Equipment, Policy	Premises and equipment. Premises and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization are principally computed on the straight-line method over the estimated useful lives of the assets. Useful lives generally range from 10 to 40 years for building and building improvements; 3 to 10 years for furniture, fixtures and equipment; and 3 to 5 years for software, hardware and data handling equipment. Land improvements are depreciated over 20 years and leasehold improvements are depreciated over the lesser of the term of the respective lease or the useful life of the asset. Premises and equipment are evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Maintenance and repairs are expensed as incurred.
Goodwill and Intangible Assets, Policy	Goodwill and other indefinite lived intangible assets. Under accounting for business combinations, the net assets of entities acquired by First Financial are recorded at their estimated fair value at the date of acquisition. The excess cost of the acquisition over the fair value of net assets acquired is recorded as goodwill. Goodwill and intangible assets deemed to have indefinite lives, if any, are not amortized, but are subject to annual impairment tests. The Company is required to evaluate goodwill for impairment on an annual basis or whenever events or changes in circumstances indicate that the carrying value may not be recoverable. First Financial performs its annual impairment test effective October 1, absent events or changes in circumstances that indicate the carrying value of goodwill may not be recoverable. The Company’s goodwill is accounted for in a single reporting unit representing the consolidated entity. Fair value is estimated using the market capitalization of the Company, as of the annual impairment testing date. First Financial also utilizes additional information and analysis to corroborate the use of the Company’s market capitalization as a proper indicator of fair value for purposes of the annual goodwill impairment test.
Goodwill and Intangible Assets, Goodwill, Policy	Goodwill is not amortized, but is measured for impairment on an annual basis as of October 1 of each year, or whenever events or changes in circumstances indicate that the fair value of a reporting unit may be below its carrying value. First Financial performed its annual impairment test of goodwill as of October 1, 2016 and no impairment was indicated. As of December 31, 2016, no events or changes in circumstances indicated that the fair value of a reporting unit was below its carrying value. Goodwill. Assets and liabilities acquired in a business combination are recorded at their estimated fair values as of the acquisition date. The excess cost of the acquisition over the fair value of net assets acquired is recorded as goodwill.
Core Deposit Intangibles Policy	Core deposit intangibles. Core deposit intangibles represent the estimated value of acquired customer deposit relationships. CDI are recorded at estimated fair value at the date of acquisition and are based on a discounted cash flow methodology that gives appropriate consideration to expected customer attrition rates, cost of the deposit base, reserve requirements and the net maintenance cost attributable to customer deposits. Core deposit intangibles are amortized on an accelerated basis over their estimated useful lives.
Affordable Housing Program Policy	Affordable housing projects. First Financial has made investments in certain qualified affordable housing projects. These projects are an indirect federal subsidy that provide tax incentives to encourage investment in the development, acquisition and rehabilitation of affordable rental housing, and allow investors to claim tax credits and other tax benefits (such as deductions from taxable income for operating losses) on their federal income tax returns. The principal risk associated with qualified affordable housing investments is the potential for noncompliance with the tax code requirements, such as, failure to rent property to qualified tenants, resulting in unavailability or recapture of the tax credits and other tax benefits. Investments in affordable housing projects are accounted for under the proportional amortization method and are included in Accrued interest and other assets in the Consolidated Balance Sheets.
Income Tax, Policy	Income taxes. First Financial and its subsidiaries file a consolidated federal income tax return. Each subsidiary provides for income taxes on a separate return basis, and remits to First Financial amounts determined to be currently payable. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Interest and penalties on income tax assessments or income tax refunds are recognized as a component of noninterest expense in the Consolidated Statements of Income.
Pension and Other Postretirement Plans, Pensions, Policy	Pension. First Financial sponsors a non-contributory defined benefit pension plan covering substantially all employees. The measurement of the accrued benefit liability and the annual pension expense involves actuarial and economic assumptions, including those related to the discount rate, the expected return on plan assets and the rate of compensation increase.
Derivatives, Policy	Derivative instruments. First Financial accounts for its derivative financial instruments in accordance with FASB ASC Topic 815, Derivatives and Hedging. FASB ASC Topic 815 requires all derivative instruments to be carried at fair value on the balance sheet. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative and the resulting designation. Derivatives used to hedge the exposure to changes in the fair value of an asset, liability or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives used to hedge the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Client derivatives - First Financial utilizes interest rate swaps as a means to offer commercial borrowers fixed rate funding while providing the Company with floating rate assets. Upon entering into an interest rate swap with a borrower, the Bank simultaneously enters into an offsetting swap agreement, with substantially matching terms, with an institutional counterparty. These matched interest rate swap agreements generally involve the receipt by First Financial of floating rate amounts from the counterparties in exchange for payments to these counterparties by First Financial of fixed rate amounts received from commercial borrowers over the life of the agreements. First Financial's matched interest rate swaps qualify as derivatives, but are not designated as hedging instruments. The net interest receivable or payable on matched interest rate swaps is accrued and recognized as an adjustment to interest income. The fair values of back to back swaps are included within Accrued interest and other assets and Accrued interest and other liabilities on the Consolidated Balance Sheets. Credit derivatives - In conjunction with participating interests in commercial loans, First Financial periodically enters into risk participation agreements with counterparties whereby First Financial assumes a portion of the credit exposure associated with an interest rate swap on the participated loan in exchange for a fee. Under these agreements, First Financial will make payments to the counterparty if the loan customer defaults on its obligation to perform under the interest rate swap contract with the counterparty. The fair value of these agreements is recorded on the Consolidated Balance Sheets in Accrued interest and other liabilities. Mortgage derivatives - First Financial enters into IRLCs and forward commitments for the future delivery of mortgage loans to third party investors, which are considered derivatives. When borrowers secure an IRLC with First Financial and the loan is intended to be sold, First Financial will enter into forward commitments for the future delivery of the loans to third party investors in order to hedge against the effect of changes in interest rates impacting IRLCs and and Loans held for sale. The fair value of these agreements is recorded on the Consolidated Balance Sheets in Accrued interest and other assets. Like other financial instruments, derivatives contain an element of credit risk, which is the possibility that First Financial will incur a loss because a counterparty fails to meet its contractual obligations. Generally, the credit risk associated with interest rate swaps is significantly less than the notional values associated with these instruments. The notional values represent contractual balances on which the calculations of amounts to be exchanged are based. First Financial manages this credit risk through counterparty credit policies.
Share-based Compensation, Option and Incentive Plans Policy	Stock-based compensation. First Financial grants stock-based awards, including restricted stock awards and options to purchase the Company’s common stock. Stock option grants are for a fixed number of shares to employees and directors with an exercise price equal to the fair value of the shares at the date of grant. Stock-based compensation expense is recognized in the Consolidated Statements of Income on a straight-line basis over the vesting period, and reflects estimated forfeitures. As compensation expense is recognized, a deferred tax asset is recorded that represents an estimate of the future tax deduction from exercise. At the time stock-based awards are exercised, canceled or expire, First Financial may be required to recognize an adjustment to tax expense.
Earnings Per Share, Policy	Earnings per share. Basic earnings per common share is computed by dividing net income available to common shareholders by the weighted average number of shares of common stock outstanding during the period. Diluted earnings per common share is computed by dividing net income available to common shareholders by the weighted average number of common shares outstanding, unvested shares and dilutive common stock equivalents outstanding during the period. Common stock equivalents, which consist of common stock issuable under the assumed exercise of stock options granted under First Financial's stock-based compensation plans and the assumed conversion of common stock warrants, are calculated using the treasury stock method.
Cash and Cash Equivalents, Policy	Cash and due from banks. Cash and due from banks consist of currency, coin and cash items due from banks. Cash items due from banks include noninterest bearing deposits held at other banks.
Loans and Leases Receivable, Nonaccrual Loan and Lease Status, Policy	Nonaccrual. Loans are classified as nonaccrual when, in the opinion of management, collection of principal or interest is doubtful or when principal or interest payments are 90 days or more past due. Generally, loans are classified as nonaccrual due to the continued failure to adhere to contractual payment terms by the borrower coupled with other pertinent factors, such as, insufficient collateral value. The accrual of interest income is discontinued and previously accrued, but unpaid interest is reversed when a loan is classified as nonaccrual. Any payments received while a loan is on nonaccrual status are applied as a reduction to the carrying value of the loan. A loan may be returned to accrual status if collection of future principal and interest payments is no longer doubtful. Purchased impaired loans are classified as performing, even though they may be contractually past due, as any nonpayment of contractual principal or interest is considered in the periodic re-estimation of expected cash flows and is included in the resulting recognition of current period covered loan loss provision or prospective yield adjustments.
Impaired Financing Receivable, Policy	Loans classified as nonaccrual and loans modified as TDRs are considered impaired.
Loans and Leases Receivable, Real Estate Acquired Through Foreclosure, Policy	OREO is comprised of properties acquired by the Company primarily through the loan foreclosure or repossession process, or other resolution activities that result in partial or total satisfaction of problem loans.
Fair Value of Financial Instruments, Policy	Fair Value Measurement The fair value framework as disclosed in the Fair Value Measurements and Disclosure Topic of FASB ASC Topic 825, Financial Instruments (Fair Value Topic), includes a hierarchy which focuses on prioritizing the inputs used in valuation techniques. The fair value hierarchy gives the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1), a lower priority to observable inputs other than quoted prices in active markets for identical assets and liabilities (Level 2), and the lowest priority to unobservable inputs (Level 3). When determining the fair value measurements for assets and liabilities, First Financial looks to active markets to price identical assets or liabilities whenever possible and classifies such items in Level 1. When identical assets and liabilities are not traded in active markets, First Financial looks to observable market data for similar assets and liabilities and classifies such items as Level 2. Certain assets and liabilities are not actively traded in observable markets and First Financial must use alternative techniques, based on unobservable inputs, to determine the fair value and classifies such items as Level 3. The level within the fair value hierarchy is based on the lowest level of input that is significant in the fair value measurement. The following methods, assumptions and valuation techniques were used by First Financial to measure different financial assets and liabilities at fair value and in estimating its fair value disclosures for financial instruments. Cash and short-term investments. The carrying amounts reported in the Consolidated Balance Sheets for cash and short-term investments, such as federal funds sold, approximated the fair value of those instruments. The Company classifies cash and short-term investments in Level 1 of the fair value hierarchy. Investment securities. Investment securities classified as trading and available-for-sale are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted market prices, when available (Level 1). If quoted market prices are not available, fair values are measured utilizing independent valuation techniques of identical or similar investment securities. First Financial compiles prices from various sources who may apply such techniques as matrix pricing to determine the value of identical or similar investment securities (Level 2). Matrix pricing is a mathematical technique widely used in the banking industry to value investment securities without relying exclusively on quoted prices for the specific investment securities but rather relying on the investment securities’ relationship to other benchmark quoted investment securities. Any investment securities not valued based upon the methods above are considered Level 3. First Financial utilizes values provided by third-party pricing vendors to price the investment securities portfolio in accordance with the fair value hierarchy of the Fair Value Topic and reviews the pricing methodologies utilized by the pricing vendors to ensure that the fair value determination is consistent with the applicable accounting guidance. First Financial’s pricing process includes a series of quality assurance activities where prices are compared to recent market conditions, historical prices and other independent pricing services. Further, the Company periodically validates the fair values of a sample of securities in the portfolio by comparing the fair values to prices from other independent sources for the same or similar securities. First Financial analyzes unusual or significant variances, conducts additional research with the pricing vendor, and if necessary, takes appropriate action based on its findings. The results of the quality assurance process are incorporated into the selection of pricing providers by the portfolio manager. Other investments. Other investments include holdings in FRB and FHLB stock, which are carried at cost due to the inability to determine the fair value as a result of restrictions placed on transferability. Loans held for sale. Loans held for sale are carried at the lower of cost or fair value. These loans currently consist of one-to-four family residential real estate loans originated for sale to qualified third parties. Fair value is based on the market price or contractual price to be received from these third parties, which is not materially different than cost due to the short duration between origination and sale (Level 2). As such, First Financial records any fair value adjustments on a nonrecurring basis. Gains and losses on the sale of loans are recorded as net gains from sales of loans within Noninterest income in the Consolidated Statements of Income. Loans and leases. The fair value of C&I, commercial real estate, residential real estate and consumer loans was estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or repricing frequency. The Company classifies the estimated fair value of loans as Level 3 in the fair value hierarchy. Impaired loans are specifically reviewed for purposes of determining the appropriate amount of impairment to be allocated to the ALLL. Fair value is generally measured based on the value of the collateral securing the loans. Collateral may be in the form of real estate or business assets including equipment, inventory and accounts receivable. The value of real estate collateral is determined utilizing an income or market valuation approach based on an appraisal conducted by an independent, licensed third-party appraiser (Level 3). The value of business equipment is based upon an outside appraisal, if deemed significant, or the net book value on the applicable borrower financial statements. Likewise, values for inventory and accounts receivable collateral are based on borrower financial statement balances or aging reports on a discounted basis as appropriate (Level 3). Impaired loans are measured at fair value on a nonrecurring basis. Any fair value adjustments are recorded in the period incurred as provision for loan and lease losses on the Consolidated Statements of Income. Fair values for purchased impaired loans are based on a discounted cash flow methodology that consider factors including the type of loan and related collateral, classification status, fixed or variable interest rate, term of loan, whether or not the loan was amortizing and a discount rate reflecting the Company's assessment of risk inherent in the cash flow estimates. These loans are grouped together according to similar characteristics and are treated in the aggregate when applying various valuation techniques. First Financial estimates the cash flows expected to be collected on these loans based upon the expected remaining life of the underlying loans, which includes the effects of estimated prepayments. Fair values for acquired loans accounted for outside of FASB ASC Topic 310-30 were estimated by discounting the future cash flows using current interest rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or repricing frequency. OREO. Assets acquired through loan foreclosure are initially recorded at fair value less costs to sell. The carrying value of OREO is not re-measured to fair value on a recurring basis, but is subject to fair value adjustments when the carrying value exceeds the fair value, less estimated selling costs. Fair value is based on recent real estate appraisals and is updated at least annually. The Company classifies OREO in level 3 of the fair value hierarchy. FDIC indemnification asset. Fair value of the FDIC indemnification asset is estimated using projected cash flows related to the loss sharing agreements based on expected reimbursements for losses and the applicable loss sharing percentages. The expected cash flows are discounted to reflect the uncertainty of the timing and receipt of the loss sharing reimbursement from the FDIC. The five year period of loss protection expired for the majority of First Financial's covered commercial loans and covered OREO effective October 1, 2014. The Company classifies the estimated fair value of the indemnification asset as Level 3 in the fair value hierarchy. Accrued interest receivable and payable. The carrying amount of accrued interest receivable and accrued interest payable approximate their fair values and is aligned with the underlying assets or liabilities (Level 1, Level 2 or Level 3). Deposits. The fair value of demand deposits, savings accounts and certain money-market deposits represents the amount payable on demand at the reporting date. The carrying amounts for variable-rate CDs approximated their fair values at the reporting date. The fair value of fixed-rate CDs is estimated using a discounted cash flow calculation which applies the interest rates currently offered for deposits of similar remaining maturities. The Company classifies the estimated fair value of deposit liabilities as Level 2 in the fair value hierarchy. Borrowings. The carrying amounts of federal funds purchased and securities sold under agreements to repurchase and other short-term borrowings approximate their fair values. The Company classifies the estimated fair value of short-term borrowings as Level 1 of the fair value hierarchy. The fair value of long-term debt is estimated using a discounted cash flow calculation which utilizes the interest rates currently offered for borrowings of similar remaining maturities. The Company classifies the estimated fair value of long-term debt as Level 2 in the fair value hierarchy. Derivatives. The fair values of derivative instruments are based primarily on a net present value calculation of the cash flows related to the interest rate swaps at the reporting date, using primarily observable market inputs such as interest rate yield curves. The discounted net present value calculated represents the cost to terminate the swap if First Financial should choose to do so. Additionally, First Financial utilizes a internally-developed model to value the credit risk component of derivative assets and liabilities, which is recorded as an adjustment to the fair value of the derivative asset or liability on the reporting date. Derivative instruments are classified as Level 2 in the fair value hierarchy.
Segment Reporting, Policy	Segments and related information. While the Company monitors the operating results of its four lines of business, the operations are managed and financial performance is evaluated on a consolidated basis. Accordingly, and consistent with prior years, all of the Company's operations are considered by management to be aggregated in one reportable operating segment.
Credit Risk
Derivatives, Methods of Accounting, Hedging Derivatives	First Financial manages this market value credit risk through counterparty credit policies. These policies require the Company to maintain a total derivative notional position of less than 35% of assets, total credit exposure of less than 3% of capital and no single counterparty credit risk exposure greater than $20.0 million.
Non Covered Loans
Finance, Loans and Leases Receivable, Policy	Loans and leases, excluding purchased impaired loans. Loans and leases for which First Financial has the intent and ability to hold for the foreseeable future, or until maturity or payoff, are classified in the Consolidated Balance Sheets as loans and leases. Loans and leases are carried at the principal amount outstanding, net of unamortized deferred loan origination fees and costs, and net of unearned income, with the exception of loans subject to fair value requirements. Loan origination and commitment fees received, as well as certain direct loan origination costs paid, are deferred, and the net amount is amortized as an adjustment to the related loan's yield. Interest income is recorded on an accrual basis. When a loan is classified as nonaccrual, the accrual of interest income is discontinued and previously accrued, but unpaid interest is reversed. Any payments received while a loan is classified as nonaccrual are applied as a reduction to the carrying value of the loan. A loan may return to accrual status if collection of future principal and interest payments is no longer doubtful.
Loans and Leases Receivable, Allowance for Loan Losses Policy	Allowance for loan and lease losses. For each reporting period, management maintains the ALLL at a level that it considers sufficient to absorb probable incurred loan and lease losses inherent in the portfolio. Management determines the adequacy of the ALLL based on historical loss experience as well as other significant factors such as composition of the portfolio, economic conditions, geographic footprint, the results of periodic internal and external evaluations of delinquent, nonaccrual and classified loans and any other adverse situations that may affect a specific borrower's ability to repay, including the timing of future payments. Management's determination of the adequacy of the ALLL is based on an assessment of the probable incurred loan and lease losses inherent in the portfolio given the conditions at the time. The ALLL is increased by provision expense and decreased by charge-offs, net of recoveries of amounts previously charged-off. First Financial's policy is to charge-off all, or a portion of a loan, when, in management's opinion, it is unlikely to collect the principal amount owed in full either through payments from the borrower or from the liquidation of collateral. Commercial loan and lease relationships (including time and demand notes, tax-exempt loans, C&I, construction, commercial real estate, mezzanine loans and lease financing) greater than $250,000 that are considered impaired, or designated as a TDR, are evaluated to determine the need for a specific allowance based on the borrower's overall financial condition, resources, payment record, guarantor support and the realizable value of any collateral. The allowance for non-impaired commercial loans and leases, as well as impaired commercial loan and lease relationships less than $250,000, includes a process of estimating the probable losses incurred in the portfolio by loan type, based on First Financial's internal system of credit risk ratings and historical loss data. These estimates may also be adjusted based upon trends in the values of the underlying collateral, delinquent and nonaccrual loans, prevailing economic conditions and changes in lending strategies, among other influencing factors. Consumer loans are generally evaluated by loan type, as these loans exhibit homogeneous characteristics. The allowance for consumer loans, which includes residential real estate, installment, home equity, credit card loans and overdrafts, is established by estimating probable losses incurred in each particular category of consumer loans. The estimate of losses is primarily based on historical loss rates for each category, as well as trends in delinquent and nonaccrual loans, prevailing economic conditions and other significant influencing factors. Consumer loans greater than $100,000 classified as TDRs are individually evaluated to determine an appropriate allowance.
Other Real Estate Owned Policy	Other real estate owned. OREO consists of properties acquired by the Company primarily through the loan foreclosure or repossession process, or other resolution activity that results in partial or total satisfaction of problem loans. OREO properties are recorded at the fair value, less estimated disposal costs (net realizable value) upon acquisition. Losses arising at the time of acquisition of such properties are charged against the ALLL. Management performs periodic valuations to assess the adequacy of the recorded OREO balances and subsequent write-downs in the carrying value of OREO properties are expensed as incurred. Improvements to OREO properties may be capitalized if the improvements contribute to the overall value of the property, but may not be capitalized in excess of the net realizable value of the property. When management disposes of an OREO property, any gains or losses realized at the time of disposal are reflected in the Consolidated Statements of Income.
Covered Loans
Finance, Loans and Leases Receivable, Policy	Acquired loans. Acquired loans are recorded at their estimated fair value at the time of acquisition. Estimated fair values for acquired loans are based on a discounted cash flow methodology that considers various factors including the type of loan and related collateral, classification status, interest rate, term of loan, whether or not the loan was amortizing and a discount rate reflecting the Company's assessment of risk inherent in the cash flow estimates. Acquired loans are grouped together according to similar characteristics and treated in the aggregate when applying various valuation techniques. First Financial evaluates acquired loans for impairment in accordance with the provisions of FASB ASC Topic 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality. Acquired loans with evidence of credit deterioration since origination are accounted for under FASB ASC Topic 310-30 and are referred to as purchased impaired loans. Interest income, through accretion of the difference between the carrying value of the loans and the expected cash flows (accretable difference) is recognized on all purchased impaired loans. For purposes of applying the guidance under FASB ASC Topic 310-30, First Financial groups acquired loans into pools based on common risk characteristics. Expected cash flows are re-estimated periodically for all purchased impaired loans. The cash flows expected to be collected are estimated based upon the expected remaining life of the underlying loans, which includes the effects of estimated prepayments. Generally, a decline in expected cash flows for a pool of loans is referred to as impairment and recorded as provision expense on a discounted basis during the period (see "Allowance for loan and lease losses" section that follows). Improvement in expected cash flows for a pool of loans, once any previously recorded impairment is recaptured, is recognized prospectively as an adjustment to the yield on the loans in the pool. These cash flow evaluations are inherently subjective as they require material estimates, all of which may be susceptible to significant change. For acquired loans that prepay, noninterest income may be recorded related to the accelerated recognition of the remaining purchase discount that would have been recognized over the life of the loan had it not prepaid. This scenario can occur either through a loan sale or prepayments that occur in the normal course of business. Acquired loans outside of the scope of FASB ASC Topic 310-30 are accounted for under FASB ASC Topic 310-20, Receivables-Nonrefundable Fees and Costs. Discounts created when the loans were recorded at their estimated fair values at acquisition are amortized over the remaining term of the loan as an adjustment to the related loan's yield. The accrual of interest income is discontinued when the collection of a loan or interest, in whole or in part, is doubtful. Certain loans acquired in FDIC-assisted transactions were initially covered under loss sharing agreements and are referred to as covered loans during the indemnification period. Subsequent to the indemnification period, they are referred to as formerly covered loans.
Loans and Leases Receivable, Allowance for Loan Losses Policy	For purchased impaired loans, expected cash flows are re-estimated periodically with declines in gross expected cash flows recorded as provision expense during the period. The related, estimated reimbursement for loan losses due from the FDIC under loss sharing agreements, if applicable, is recorded as FDIC loss sharing income.
Fair Value Hedges
Derivatives, Methods of Accounting, Hedging Derivatives	. First Financial utilizes interest rate swaps as a means to offer commercial borrowers fixed rate funding while providing the Company with floating rate assets.