ALLOWANCE FOR LOAN AND LEASE LOSSES - Additional Information (Details) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Net charge-offs	$ (536,000)	$ 6,100,000	$ 7,022,000
Provision for loan and lease losses	(283,000)	(2,192,000)	(1,841,000)
Allowance for covered loan losses	10,300,000ffbc_AllowanceForCoveredAssetLosses	10,600,000ffbc_AllowanceForCoveredAssetLosses
Loss sharing expense	301,000ffbc_LossSharingExpense	1,569,000ffbc_LossSharingExpense
Loss (gain) - covered other real estate owned	300,000	0
FDIC loss sharing income	$ (1,046,000)ffbc_FdicIndemnificationIncome	$ (508,000)ffbc_FdicIndemnificationIncome

Allowance for losses on loans subject to loss share agreements.

No definition available.

Name:	ffbc_AllowanceForCoveredAssetLosses
Namespace Prefix:	ffbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Allowance for Credit Losses, Covered Loans, Net Charge Offs

+ References

No definition available.

+ Details

Name:	ffbc_AllowanceForCreditLossesCoveredLoansNetChargeOffs
Namespace Prefix:	ffbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expected reimbursements from the FDIC for losses on covered assets.

+ References

No definition available.

+ Details

Name:	ffbc_FdicIndemnificationIncome
Namespace Prefix:	ffbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net gain (loss) resulting from sales and other disposals of covered other real estate owned, increases (decreases) in the valuation allowance for covered foreclosed real estate, and write-downs of covered other real estate owned after acquisition or physical possession.

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No definition available.

+ Details

Name:	ffbc_GainsLossesOnSalesOfCoveredOtherRealEstate
Namespace Prefix:	ffbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Expenses associated with covered assets (loans and other real estate owned) resolution and collection

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No definition available.

+ Details

Name:	ffbc_LossSharingExpense
Namespace Prefix:	ffbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The sum of the periodic provision charged to operations, based on an assessment of the uncollectibility of the loan and lease portfolio on covered loans, the offset to which is either added to or deducted from the allowance account for the purpose of reducing loan receivable and leases to an amount that approximates their net realizable value (the amount expected to be collected).

+ References

No definition available.

+ Details

Name:	ffbc_ProvisionForLoanAndLeaseLossesCovered
Namespace Prefix:	ffbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration