XML 61 R52.htm IDEA: XBRL DOCUMENT
v3.23.1

Loans and Allowance for Credit Losses - Schedule of Amortized Cost Basis of Collateral Dependent Loans (Details) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2023 USD ($)
Total loans individually evaluated | $ 3,676
Direct Consumer [Member] |
Total loans individually evaluated | 18
Real Estate [Member] | Secured by Real Estate 1-4 Family Residential Properties [Member] |
Total loans individually evaluated | 545
Real Estate [Member] | Secured By Non-farm Non residential Properties [Member] |
Total loans individually evaluated | 2,776
Commercial And Industrial Loans [Member] |
Total loans individually evaluated | 337
Real Estate [Member] |
Total loans individually evaluated | 3,321
Real Estate [Member] | Real Estate [Member] | Secured by Real Estate 1-4 Family Residential Properties [Member] |
Total loans individually evaluated | 545
Real Estate [Member] | Real Estate [Member] | Secured By Non-farm Non residential Properties [Member] |
Total loans individually evaluated | 2,776
Other [Member] |
Total loans individually evaluated | 355
Other [Member] | Direct Consumer [Member] |
Total loans individually evaluated | 18
Other [Member] | Commercial And Industrial Loans [Member] |
Total loans individually evaluated | $ 337

X
- Definition Collateral Loans Individually Evaluated Amortized Cost Basis + References No definition available. + Details
Name: | fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis
Namespace Prefix: | fusb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fusb_DirectConsumerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fusb_RealEstate1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fusb_SecuredByNonfarmNonresidentialPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fusb_CommercialAndIndustrialLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=us-gaap_RealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=fusb_OtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |