DERIVATIVES - Additional Information (Details) (USD $)	12 Months Ended
Dec. 31, 2014 entity	Mar. 31, 2015 entity
Derivative [Line Items]
Maximum derivative notional position as a percentage of assets		35.00%
Maximum credit exposure as a percentage of capital		3.00%
Maximum single counterparty credit risk exposure	$ 20,000,000
Inerest-bearing deposit liability	823,585,000invest_DerivativeNotionalAmount	894,227,000invest_DerivativeNotionalAmount
Number of counterparties	9ffbc_NumberOfDerivativeCounterparty	9ffbc_NumberOfDerivativeCounterparty
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	11,916,000us-gaap_DerivativeLiabilities	14,797,000us-gaap_DerivativeLiabilities
Credit Derivative Term	3 years 8 months
Interest Rate Cash Flow Hedge Asset at Fair Value	(1,700,000)	(3,000,000)
Outstanding liability from counterparty contracts	100,000	100,000
Cash Flow Hedging [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	150,000,000	150,000,000
Other Credit Derivatives [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	26,400,000	26,300,000
Accrued interest and other liabilities \| Derivative [Member]
Derivative [Line Items]
Inerest-bearing deposit liability	566,200,000	600,600,000
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$ 12,400,000	$ 17,100,000

Credit Risk Derivatives, Maximum Percent of Credit Exposure to Capital

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- Definition

Credit Risk Derivatives, Maximum Percent of Derivative Notional Amounts to Assets

+ References

No definition available.

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- Definition

Number Of Derivative Counterparty

+ References

No definition available.

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

+ Details

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- Definition

Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13537-108611

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- Definition

Term of the credit risk derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4K

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5708775-113959

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- Definition

Fair value of credit risk derivative liability.

+ References

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13495-108611

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226008-175313

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- Definition

Fair value as of the balance sheet date of all interest rate derivatives designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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