SIGNIFICANT ACCOUNTING POLICIES (Policy)	9 Months Ended
SIGNIFICANT ACCOUNTING POLICIES (Policy)	Sep. 30, 2011
Goodwill and Intangible Assets, Goodwill, Policy	Goodwill Assets and liabilities of acquired entities are recorded at their estimated fair values as of the acquisition date. First Financial recorded $17.1 million of goodwill during the third quarter of 2011 related to the Liberty banking center acquisition. 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 as of October 1, 2010, and no impairment was indicated. As of September 30, 2011, no events or changes in circumstances indicated that the fair value of a reporting unit was below its carrying value.
Goodwill and Intangible Assets, Intangible Assets, Policy	Other intangible assets Other intangible assets consist of mortgage servicing rights and core deposit intangibles. Mortgage servicing rights are carried at their estimated fair value. Core deposit intangibles are recorded at their estimated fair value as of acquisition and are then amortized on an accelerated basis over their estimated useful lives. First Financial recorded $4.0 million of core deposit intangibles associated with the Liberty banking center acquisition during the third quarter of 2011. Core deposit intangibles have an estimated weighted average remaining life of 8.67 years.
Commitments and Contingencies, Policy	In the normal course of business, First Financial offers a variety of financial instruments with off-balance-sheet risk to its clients to aid them in meeting their requirements for liquidity and credit enhancement. These financial instruments include standby letters of credit and outstanding commitments to extend credit. U.S. generally accepted accounting principles do not require these financial instruments to be recorded in the Consolidated Balance Sheets, Consolidated Statements of Income, Consolidated Statements of Changes in Shareholders’ Equity, and Consolidated Statements of Cash Flows. Following is a discussion of these transactions. First Financial’s exposure to credit loss, in the event of nonperformance by the other party 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 uses the same credit policies in making commitments and conditional obligations as it does for on-balance-sheet instruments.
Certain Loans and Debt Securities Acquired in Transfer, Recognizing Interest Income on Impaired Loans, Policy	All loans acquired in the Peoples and Irwin acquisitions were covered by loss sharing agreements with the FDIC, whereby the FDIC reimburses First Financial for the majority of the losses incurred. Additionally, these loans were recorded at their estimated fair value as of the acquisition date. Generally the determination of the fair value of the loans resulted in a significant write-down in the value of the loans, which was assigned to an accretable or nonaccretable difference, with the accretable difference to be recognized as interest income over the expected remaining term of the loan. First Financial evaluates purchased loans for impairment in accordance with the provisions of FASB ASC Topic 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality. The cash flows expected to be collected on purchased loans are estimated based upon the expected remaining life of the underlying loans, which includes the effects of estimated prepayments. Purchased loans are considered impaired if there is evidence of credit deterioration since origination and if it is probable that not all contractually required payments will be collected. First Financial is accounting for the majority of purchased loans under FASB ASC Topic 310-30 except loans with revolving privileges, which are outside the scope of this guidance, and loans for which cash flows could not be estimated, which are accounted for under the cost recovery method. Purchased impaired loans were not classified as nonperforming assets at September 30, 2011 as the loans are considered to be performing under FASB ASC Topic 310-30. Therefore, interest income, through accretion of the difference between the carrying value of the loans and the expected cash flows is being recognized on all purchased loans being accounted for under FASB ASC Topic 310-30.
Fair Value of Financial Instruments, Policy	Fair Value Measurement The fair value framework as disclosed in the Fair Value Measurements and Disclosure Topic of the FASB Accounting Standards Codification (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 market observable 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. 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. Third party vendors compile prices from various sources and 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 information provided by a third party investment securities portfolio manager in analyzing the investment securities portfolio in accordance with the fair value hierarchy of the Fair Value Topic. The portfolio manager’s evaluation of investment security portfolio pricing is performed using a combination of prices and data from third party vendors, along with internally developed matrix pricing models and assistance from the provider’s internal fixed income analysts and trading desk. The portfolio manager’s month-end pricing process includes a series of quality assurance activities where prices are compared to recent market conditions, previous evaluation prices, and between the various pricing services. These processes produce a series of quality assurance reports on which price exceptions are identified, reviewed, and where appropriate, securities are repriced. In the event of a materially different price, the portfolio manager will report the variance to the third party vendor as a “price challenge”, and review the pricing methodology in detail. The results of the quality assurance process are incorporated into the selection of pricing providers by the portfolio manager. Loans held for sale – Loans held for sale are carried at the lower of cost or market 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 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 (excluding covered loans) – The fair value of commercial, commercial real estate, residential real estate, and consumer loans were 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 carrying amount of accrued interest approximates its fair value. Loans are designated as impaired when, in the judgment of management based on current information and events, it is probable that all amounts due according to the contractual terms of the loan agreement will not be collected. Impaired loans are valued at the lower of cost or market for purposes of determining the appropriate amount of impairment to be allocated to the allowance for loan and lease losses. Market value is 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 vast majority of the collateral is real estate. The value of real estate collateral is determined utilizing an income or market valuation approach based on an appraisal conducted by an independent, licensed appraiser from outside of the Company (Level 2). 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 if not considered significant. Likewise, values for inventory and accounts receivable collateral are based on borrower financial statement balances or aging reports (Level 3). Impaired loans allocated to the allowance for loan and lease losses 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. Covered loans – Fair values for covered loans accounted for under FASB ASC 310-30 were based on a discounted cash flow methodology that considered factors including the type of loan and related collateral, classification status, fixed or variable interest rate, term of loan and whether or not the loan was amortizing, and a discount rate reflecting the Company's assessment of risk inherent in the cash flow estimates. Covered loans were grouped together according to similar characteristics and were treated in the aggregate when applying various valuation techniques. First Financial estimated 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 covered loans accounted for outside of FASB ASC Topic 310-30 were estimated by discounting the estimated 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. The carrying amount of accrued interest approximates its fair value. These cash flow evaluations are inherently subjective as they require material estimates, all of which may be susceptible to significant change. Mortgage-servicing rights – The fair value of mortgage-servicing rights was determined through modeling the expected future cash flows. The modeling included stratification by maturity and coupon rates on the underlying mortgage loans. Certain assumptions were used in the valuation regarding prepayment speeds, discount rates, servicing costs, delinquency, cash balances, and foreclosure costs which were arrived at from third-party sources and internal records. FDIC indemnification asset – The accounting for FDIC indemnification assets is closely related to the accounting for the underlying, indemnified assets. Fair value of the FDIC indemnification asset was estimated using projected cash flows related to the loss sharing agreements based on the expected reimbursements for losses and the applicable loss sharing percentages. First Financial re-estimates the expected indemnification asset cash flows in conjunction with the periodic re-estimation of cash flows on covered loans accounted for under FASB ASC Topic 310-30. Improvements in cash flow expectations on covered loans generally result in a related decline in the expected indemnification cash flows while declines in cash flow expectations on covered loans generally result in an increase in expected indemnification cash flows. The expected cash flows are discounted to reflect the uncertainty of the timing and receipt of the loss sharing reimbursement from the FDIC. These cash flow evaluations are inherently subjective as they require material estimates, all of which may be susceptible to significant change. Deposit liabilities – The fair value of demand deposits, savings accounts, and certain money-market deposits was the amount payable on demand at the reporting date. The carrying amounts for variable-rate certificates of deposit approximated their fair values at the reporting date. The fair value of fixed-rate certificates of deposit was estimated using a discounted cash flow calculation which applies the interest rates currently offered for deposits of similar remaining maturities. The carrying amount of accrued interest approximated its fair value. Borrowings – The carrying amounts of federal funds purchased and securities sold under agreements to repurchase and other short-term borrowings approximated their fair values. The fair value of long-term debt was estimated using a discounted cash flow calculation which utilizes the interest rates currently offered for borrowings of similar remaining maturities. Third-party valuations were used for long-term debt with embedded options, such as call features. Commitments to extend credit and standby letters of credit – Pricing of these financial instruments is based on the credit quality and relationship, fees, interest rates, probability of funding and compensating balance and other covenants or requirements. Loan commitments generally have fixed expiration dates, are variable rate and contain termination and other clauses which provide for relief from funding in the event that there is a significant deterioration in the credit quality of the client. Many loan commitments are expected to expire without being drawn upon. The rates and terms of the commitments to extend credit and the standby letters of credit are competitive with those in First Financial’s market area. The carrying amounts are reasonable estimates of the fair value of these financial instruments. Carrying amounts, which are comprised of the unamortized fee income and, where necessary, reserves for any expected credit losses from these financial instruments, are immaterial. Derivatives – First Financial utilizes interest rate swaps as a means to offer commercial borrowers products that meet their needs and also to achieve First Financial’s desired interest rate risk profile at the time. The net interest receivable or payable is accrued and recognized as an adjustment to the interest income or interest expense of the hedged item. First Financial utilizes third-party vendors for derivative valuation purposes. These vendors determine the appropriate fair value based on a net present value calculation of the cash flows related to the interest rate swaps 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 on the applicable measurement date (Level 2). Additionally, First Financial utilizes a vendor developed, proprietary model to value the credit risk component of both the derivative assets and liabilities. The credit valuation adjustment is recorded as an adjustment to the fair value of the derivative asset or liability on the applicable measurement date (Level 3).
Fair Value Hedges
Derivatives, Methods of Accounting, Hedging Derivatives	Fair Value Hedges - First Financial utilizes interest rate swaps as a means to offer commercial borrowers products that meet their needs, but are also designed to achieve First Financial’s desired interest rate risk profile at the time. The fair value hedge agreements generally involve the net receipt by First Financial of floating-rate amounts in exchange for net payments by First Financial, through its loan clients, of fixed-rate amounts over the life of the agreements without an exchange of the underlying principal or notional amount. This results in First Financial’s loan customers receiving fixed rate funding, while providing First Financial with a floating rate asset. The net interest receivable or payable on the interest rate swaps is accrued and recognized as an adjustment to the interest income or interest expense of the hedged item. The fair value of the interest rate swaps is included within accrued interest and other assets on the Consolidated Balance Sheets. The corresponding fair-value adjustment is also included on the Consolidated Balance Sheets in the carrying value of the hedged item. Derivative gains and losses not considered effective in hedging the change in fair value of the hedged item are recognized immediately in income.
Cash Flow Hedges
Derivatives, Methods of Accounting, Hedging Derivatives	Cash Flow Hedges – First Financial may utilize interest rate swaps designated as cash flow hedges to manage the variability of cash flows, primarily net interest income, attributable to changes in interest rates. The net interest receivable or payable on an interest rate swap designated as a cash flow hedge is accrued and recognized as an adjustment to interest income or interest expense. The fair value of the interest rate swaps is included within accrued interest and other assets on the Consolidated Balance Sheets. Changes in the fair value of the interest rate swaps are included in accumulated comprehensive income (loss). Derivative gains and losses not considered effective in hedging the cash flows related to the underlying loans, if any, would be recognized immediately in income.
Non Covered Loans
Loans and Leases Receivable, Nonaccrual Loan and Lease Status, Policy	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 placed in nonaccrual status 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 placed in nonaccrual status. Any payments received while a loan is in nonaccrual status are applied as a reduction to the carrying value of the loan. A loan may be placed back on accrual status if all contractual payments have been received and collection of future principal and interest payments is no longer doubtful.
Impaired Financing Receivable, Policy	In the commercial portfolio, management reviews all impaired loan relationships in excess of $250,000 to determine if a specific allowance based on the borrower’s overall financial condition, resources and payment record, support from guarantors, and the realizable value of any collateral is necessary. Specific allowances are based on discounted cash flows using the loan's initial effective interest rate or the fair value of the collateral for certain collateral dependent loans. Interest income for impaired loans is recorded on a cash basis during the period the loan is considered impaired after recovery of principal is reasonably assured. Loans placed in nonaccrual status and restructured loans are considered impaired.
Loans and Leases Receivable, Real Estate Acquired Through Foreclosure, Policy	Other real estate owned is comprised of properties acquired by the Bank through the loan foreclosure or repossession process, or any other resolution activity that results in partial or total satisfaction of problem loans. The acquired properties are recorded at the lower of cost, or fair value less estimated costs of disposal (net realizable value), upon acquisition. Losses arising at the time of acquisition of such properties are charged against the allowance for loan and lease losses. Subsequent write-downs in the carrying value of OREO properties are expensed as incurred. Improvements to the 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.
Loans and Leases Receivable, Allowance for Loan Losses Policy	For each reporting period, management maintains the allowance at a level that it considers sufficient to absorb inherent risks in the loan portfolio. Management’s evaluation in establishing the adequacy of the allowance includes evaluation of the loan and lease portfolios, actual past loan and lease loss experience, known and inherent risks in the portfolio, adverse situations that may affect a specific borrower’s ability to repay (including the timing of future payments), the estimated value of any underlying collateral, composition of the loan portfolio, economic conditions, and other pertinent factors, such as periodic internal and external evaluations of delinquent, nonaccrual, and classified loans. The evaluation is inherently subjective as it requires utilizing material estimates, including the amounts and timing of future cash flows expected to be received on impaired loans. The evaluation of these factors is the responsibility of the Allowance for Loan and Lease Losses Committee, which is comprised of senior officers from the risk management, credit administration, finance, and lending areas. The allowance for commercial loans, including time and demand notes, tax-exempt loans, and commercial real estate loans begins with a process of estimating the probable losses inherent in the portfolio. The loss estimates for these commercial loans are established by category and based on First Financial’s internal system of credit risk ratings and historical loss data. The estimate of losses inherent in the commercial portfolio may be adjusted for management’s estimate of probable losses on specific exposures dependent upon the values of the underlying collateral and/or the present value of expected future cash flows, as well as trends in delinquent and nonaccrual loans, prevailing economic conditions, changes in lending strategies, and other influencing factors. In the commercial portfolio, certain loans, typically larger-balance non-homogeneous exposures, may have a specific allowance established based on the borrower’s overall financial condition, resources and payment record, support from guarantors, and the realizable value of any collateral. The allowance for consumer loans which includes residential real estate, installment, home equity, credit card loans, and overdrafts, is established for each of the categories by estimating losses inherent in that particular category of consumer loans. The estimate of losses is primarily based on historical loss rates for the category, as well as trends in delinquent and nonaccrual loans, prevailing economic conditions, and other influencing factors. Consumer loans are evaluated as an asset type within a category (i.e., residential real estate, installment, etc.), as these loans are smaller with more homogeneous characteristics. There were no material changes to First Financial’s accounting policies or methodology related to the allowance for loan and lease losses during the third quarter of 2011. First Financial’s policy is to charge-off loans when, in management’s opinion, full collectibility of principal and interest based upon the contractual terms of the loan is unlikely.
Covered Loans
Loans and Leases Receivable, Real Estate Acquired Through Foreclosure, Policy	Covered other real estate owned is comprised of properties acquired by the Bank through the loan foreclosure or, repossession process, or any other resolution activity that results in partial or total satisfaction of problem covered loans. These properties remain subject to loss share agreements whereby the FDIC reimburses First Financial for the majority of any losses incurred. The acquired properties are recorded at the lower of cost, or fair value less estimated costs of disposal (net realizable value), upon acquisition. Losses arising at the time of acquisition of such properties are charged against the allowance for loan and lease losses. Subsequent write-downs in the carrying value of covered OREO properties are expensed as incurred. Improvements to the 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.
Loans and Leases Receivable, Allowance for Loan Losses Policy	Under the applicable accounting guidance, the allowance for loan losses related to covered loans as a result of impairment to loan pools arising from on-going valuation procedures is generally recognized in the current period as provision expense. Improvement in the credit outlook, however, is not recognized immediately but instead is reflected as an adjustment to the yield earned on the related loan pools on a prospective basis once any previously recorded impairment has been recaptured. The timing inherent in this accounting treatment may result in earnings volatility in future periods.
Covered Loans \| Loans Accounted for Under FASB ASC Topic 310-30
Loans and Leases Receivable, Nonperforming Loan and Lease, Policy	Covered loans accounted for under FASB ASC Topic 310-30 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.
Covered Loans \| Loans Excluded from FASB ASC Topic 310-30
Loans and Leases Receivable, Nonaccrual Loan and Lease Status, Policy	Similar to uncovered loans, covered loans accounted for outside FASB ASC Topic 310-30 are classified as nonaccrual when, in the opinion of management, collection of principal or interest is doubtful. Generally, these loans are placed in nonaccrual status 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 when a loan is placed in nonaccrual status and any payments received reduce the carrying value of the loan. A loan may be placed back on accrual status if all contractual payments have been received and collection of future principal and interest payments is no longer doubtful.
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.