Name:	fgbi_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForPurchasedCreditImpairment
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Average recorded investment in financing receivables after undergoing trouble debt restructuring that are on nonaccrual status as of the balance sheet date.

No definition available.

Name:	fgbi_FinancingReceivableAverageRecordedInvestmentNonaccrualStatus
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The balance of financing receivables that were individually evaluated for purchased credit impairment.

No definition available.

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Refers to the amount related to loans totaling not accruing interest.

No definition available.

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- References

No definition available.

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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
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Amount of fee received for commitment to originate or purchase financing receivable where likelihood of commitment being exercised is remote, to be recognized as service income.

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Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Amortized cost excluding accrued interest, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
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The balance of financing receivables that were individually evaluated for impairment.

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-Topic 310
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Amortized cost of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_ConstructionAndLandDevelopmentMember
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Data Type:	na
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_FarmlandMember
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_OneToFourFamilyMember
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_Multi-FamilyMember
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_NonFarmNonResidentialMember
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Data Type:	na
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Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fgbi_NonRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_AgriculturalMember
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_CommercialAndIndustrialMember
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Data Type:	na
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_CommercialLeasesMember
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Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fgbi_ConsumerAndOtherMember
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