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Fair Value of FInancial Instruments - Additional Information (Detail) (USD $) | 12 Months Ended |
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Dec. 31, 2014 | Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Interest-bearing deposits maturing date | 90 days |
Business Combination, cost incurred | $ 231,400 us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable |
Business Combination, Borrowings outstanding | 0 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt |
Carrying amounts of dividends payable, number of days | Forty days |
Impaired loans categorized as Level 3 | 1,843,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment | 2,440,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment
Specific allocation for impaired loans | 387,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance | 516,000 us-gaap_ImpairedFinancingReceivableRelatedAllowance
Asset impairment charges | 0 us-gaap_AssetImpairmentCharges |
Federal Home Loan Bank of Indianapolis [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Redemption period imposed on stock | 5 years |
Level 3 [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Impaired loans categorized as Level 3 | 1,500,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member | 1,900,000 us-gaap_ImpairedFinancingReceivableRecordedInvestment / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member
Fair Value on a Recurring Basis [Member] |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Specific allocation for impaired loans | $ 386,900 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember | $ 516,100 us-gaap_ImpairedFinancingReceivableRelatedAllowance / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember

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