XML 92 R80.htm IDEA: XBRL DOCUMENT
v3.22.1

Loans And Related Allowances For Loan Losses (Modification of Troubled Debt Restructuring by Class) (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 USD ($) contract | Dec. 31, 2020 USD ($) contract
Temporary Rate Modification [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract |  | 1
Recorded Investment |  | $ 46
Temporary Rate Modification [Member] | Residential mortgage- term [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract |  | 1
Recorded Investment |  | $ 46
Extension Of Maturity [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract | 4 | 4
Recorded Investment | $ 610 | $ 887
Extension Of Maturity [Member] | Commercial real estate- non owner-occupied [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract | 1 |
Recorded Investment | $ 109 |
Extension Of Maturity [Member] | Acquisition and development- All other A&D [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract | 1 | 2
Recorded Investment | $ 202 | $ 430
Extension Of Maturity [Member] | Residential mortgage- term [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract | 2 | 2
Recorded Investment | $ 299 | $ 457
Modification Of Payment And Other Terms [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract |  | 4
Recorded Investment |  | $ 2,582
Modification Of Payment And Other Terms [Member] | Commercial real estate- all other CRE [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract |  | 1
Recorded Investment |  | $ 2,226
Modification Of Payment And Other Terms [Member] | Acquisition and development- All other A&D [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Recorded Investment |  | $ 0
Modification Of Payment And Other Terms [Member] | Residential mortgage- term [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of Contracts | contract |  | 3
Recorded Investment |  | $ 356

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after troubled debt restructuring, of modified financing receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=func_TemporaryRateModificationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=func_ExtensionOfMaturityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=func_ModificationOfPaymentAndOtherTermsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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