XML 59 R49.htm IDEA: XBRL DOCUMENT
v3.20.2

Loans And Related Allowances For Loan Losses (Narrative) (Details) |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 01, 2020 USD ($) | Oct. 30, 2020 USD ($) contract | Jul. 31, 2020 USD ($) contract | Dec. 31, 2020 USD ($) | Sep. 30, 2020 USD ($) contract | Sep. 30, 2019 USD ($) contract | Mar. 31, 2019 USD ($) | Sep. 30, 2020 USD ($) loan contract | Sep. 30, 2019 USD ($) loan | Dec. 31, 2019 USD ($) contract | Jun. 30, 2020 USD ($) | Jun. 30, 2019 USD ($) | Dec. 31, 2018 USD ($)
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan losses |  |  |  |  | $ 16,189,000 | $ 11,971,000 |  | $ 16,189,000 | $ 11,971,000 | $ 12,537,000 | $ 17,014,000 | $ 11,976,000 | $ 11,047,000
Loan charge off |  |  |  |  | 1,174,000 | 146,000 |  | 1,758,000 | 402,000 |  |  |  |
Loan recovery amount |  |  |  |  | 189,000 | $ 154,000 |  | 429,000 | $ 657,000 |  |  |  |
Nonaccrual loans |  |  |  |  | 10,344,000 |  |  | $ 10,344,000 |  | 10,849,000 |  |  |
Financing receivable, modifications, number of contracts | contract |  |  |  |  |  |  |  | 10,468 |  |  |  |  |
Financing receivable, modifications, recorded investment |  |  |  |  | 1,043,490,000 |  |  | $ 1,043,490,000 |  |  |  |  |
Substandard [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Increase in non-accrual status |  |  |  |  |  |  |  | $ 12,700,000 |  |  |  |  |
Number of well collateralized loans that increased balance of substandard category | loan |  |  |  |  |  |  |  | 2 |  |  |  |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
OREO increase (decrease) | $ 7,200,000 |  |  |  |  |  |  |  |  |  |  |  |
COVID-19 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
PPP loans |  |  |  |  | 148,900,000 |  |  | $ 148,900,000 |  |  |  |  |
Financing receivable, modifications, number of contracts | contract |  |  | 383 |  |  |  |  |  |  |  |  |  |
Financing receivable, modifications, recorded investment |  |  | $ 214,453,000 |  |  |  |  |  |  |  |  |  |
COVID-19 [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing receivable, modifications, number of contracts | contract |  | 42 |  |  |  |  |  |  |  |  |  |  |
Financing receivable, modifications, recorded investment |  | $ 19,251,000 |  |  |  |  |  |  |  |  |  |  |
CARES Act [Member] | COVID-19 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
PPP loans SBA guarantee percent |  |  |  |  |  |  |  | 100.00% |  |  |  |  |
Scenario, Forecast [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
OREO increase (decrease) |  |  |  | $ (2,000,000.0) |  |  |  |  |  |  |  |  |
New Appraisal Process [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan losses |  |  |  |  | 2,400,000 |  |  | $ 2,400,000 |  |  |  |  |
Loan recovery amount |  |  |  |  |  |  |  | 1,300,000 |  |  |  |  |
Credit losses recovery re-allocated to loans receivable allowance |  |  |  |  |  |  |  | 1,300,000 |  |  |  |  |
Partial Charge Off [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Nonaccrual loans |  |  |  |  | $ 7,300,000 |  |  | $ 7,300,000 |  | $ 200,000 |  |  |
New TDRs [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing receivable, modifications, number of contracts |  |  |  |  | 0 | 1 |  | 0 | 1 |  |  |  |
Existing TDRs [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing receivable, modifications, number of contracts |  |  |  |  | 3 | 0 |  | 9 | 2 | 15 |  |  |
Financing receivable, modifications, subsequent default, recorded investment |  |  |  |  | $ 0 | $ 0 |  |  |  |  |  |  |
Existing TDRs loans Remodified After Maturity [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing receivable, modifications, number of contracts | contract |  |  |  |  |  |  |  | 14 |  |  |  |  |
Financing receivable, modifications, recorded investment |  |  |  |  | 4,000,000.0 |  |  | $ 4,000,000.0 |  | $ 4,200,000 |  |  |
Troubled Debt Restructuring [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing receivable, modifications, subsequent default, recorded investment |  |  |  |  |  |  |  | 0 | $ 0 |  |  |  |
Commercial real estate- non owner-occupied [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Nonaccrual loans |  |  |  |  | 9,000 |  |  | 9,000 |  | 33,000 |  |  |
Commercial real estate- non owner-occupied [Member] | Special Mention [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Increase in non-accrual status |  |  |  |  |  |  |  | $ 6,500,000 |  |  |  |  |
Number of loan resulted in increase in non-accrual balances | loan |  |  |  |  |  |  |  | 3 |  |  |  |  |
Commercial real estate- all other CRE [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Nonaccrual loans |  |  |  |  | 918,000 |  |  | $ 918,000 |  | 647,000 |  |  |
Acquisition and development- 1-4 family residential construction [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Loans in process of foreclosure |  |  |  |  | 300,000 |  |  | $ 300,000 |  | 100,000 |  |  |
Percentage of loan portfolio accruing loans past due 30 days or more |  |  |  |  |  |  |  |  | 0.67% |  |  |  |
Percentage of loan portfolio accruing loans excluding PPP loans past due 30 days or more |  |  |  |  |  |  |  | 0.83% |  |  |  |  |
Acquisition and development- 1-4 family residential construction [Member] | COVID-19 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of loan portfolio accruing loans including PPP loans past due 30 days or more |  |  |  |  |  |  |  | 0.73% |  |  |  |  |
Acquisition and development- 1-4 family residential construction [Member] | Delay In Preparation Of Forbearance Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Increase in non-accrual status |  |  |  |  |  |  |  | $ 6,700,000 |  |  |  |  |
Number of loan resulted in increase in non-accrual balances | loan |  |  |  |  |  |  |  | 1 |  |  |  |  |
Acquisition and development- All other A&D [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Loan charge off |  |  |  |  |  |  |  | $ 1,100,000 |  |  |  |  |
Increase in non-accrual status |  |  |  |  |  |  | $ 8,300,000 |  |  |  |  |  |
Nonaccrual loans |  |  |  |  | 7,447,000 |  |  | 7,447,000 |  | 8,058,000 |  |  |
Acquisition and development- All other A&D [Member] | New Appraisal Process [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Loan charge off |  |  |  |  |  |  |  | 1,100,000 |  |  |  |  |
Commercial and industrial [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan losses |  |  |  |  | 2,184,000 | 1,195,000 |  | 2,184,000 | $ 1,195,000 | 1,341,000 | 1,997,000 | 1,147,000 | 1,187,000
Loan charge off |  |  |  |  |  | 70,000 |  | 232,000 | 75,000 |  |  |  |
Loan recovery amount |  |  |  |  | 133,000 | 1,000 |  | 149,000 | 77,000 |  |  |  |
Nonaccrual loans |  |  |  |  |  |  |  |  |  | 30,000 |  |  |
Commercial and industrial [Member] | CARES Act [Member] | COVID-19 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
PPP loans |  |  |  |  | 148,900,000 |  |  | $ 148,900,000 |  |  |  |  |
PPP loans SBA guarantee percent |  |  |  |  |  |  |  | 100.00% |  |  |  |  |
Allowance for loan losses |  |  |  |  | 0 |  |  | $ 0 |  |  |  |  |
Commercial and industrial [Member] | Medical Profession Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Number of loan resulted in increase in non-accrual balances | loan |  |  |  |  |  |  |  | 1 |  |  |  |  |
Residential mortgage- term [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Nonaccrual loans |  |  |  |  | 1,460,000 |  |  | $ 1,460,000 |  | 1,219,000 |  |  |
Residential mortgage- home equity [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Nonaccrual loans |  |  |  |  | 479,000 |  |  | 479,000 |  | 858,000 |  |  |
Consumer [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for loan losses |  |  |  |  | 381,000 | 312,000 |  | 381,000 | 312,000 | 312,000 | $ 386,000 | $ 319,000 | $ 315,000
Loan charge off |  |  |  |  | 51,000 | 76,000 |  | 274,000 | 212,000 |  |  |  |
Loan recovery amount |  |  |  |  | 28,000 | $ 31,000 |  | 116,000 | $ 122,000 |  |  |  |
Nonaccrual loans |  |  |  |  | $ 31,000 |  |  | $ 31,000 |  | $ 4,000 |  |  |

X
- Definition Credit Losses Recovery Re-allocated To Loans Receivable Allowance + References No definition available. + Details
Name: | func_CreditLossesRecoveryReAllocatedToLoansReceivableAllowance
Namespace Prefix: | func_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Increase In Financing Receivable Recorded Investment Nonaccrual Status + References No definition available. + Details
Name: | func_IncreaseInFinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | func_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number Of Loan Resulted In Increase In Non Aaccrual Balances + References No definition available. + Details
Name: | func_NumberOfLoanResultedInIncreaseInNonAaccrualBalances
Namespace Prefix: | func_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Well Collateralized Loans That Increased Balance Of Substandard Category + References No definition available. + Details
Name: | func_NumberOfWellCollateralizedLoansThatIncreasedBalanceOfSubstandardCategory
Namespace Prefix: | func_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Paycheck Protection Program Loan Amount + References No definition available. + Details
Name: | func_PaycheckProtectionProgramLoanAmount
Namespace Prefix: | func_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Paycheck Protection Program Loans Sba Guarantee Percent + References No definition available. + Details
Name: | func_PaycheckProtectionProgramLoansSbaGuaranteePercent
Namespace Prefix: | func_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Loan Portfolio Accruing Loans Excluding Ppp Loans Past Due Thirty Days Or More + References No definition available. + Details
Name: | func_PercentageOfLoanPortfolioAccruingLoansExcludingPppLoansPastDueThirtyDaysOrMore
Namespace Prefix: | func_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Loan Portfolio Accruing Loans Including Paycheck Protection Program Loans Past Due Thirty Days Or More + References No definition available. + Details
Name: | func_PercentageOfLoanPortfolioAccruingLoansIncludingPaycheckProtectionProgramLoansPastDueThirtyDaysOrMore
Namespace Prefix: | func_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Loan Portfolio Accruing Loans Past Due Thirty Days Or More + References No definition available. + Details
Name: | func_PercentageOfLoanPortfolioAccruingLoansPastDueThirtyDaysOrMore
Namespace Prefix: | func_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase in allowance for credit loss on financing receivable from recovery. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922352-210448 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(4) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922352-210448 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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=121611835&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 of financing receivable modified as troubled debt restructuring. + 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=121611835&loc=SL6953676-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554 + Details
Name: | us-gaap_FinancingReceivableModificationsRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524 + Details
Name: | us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of financing receivable on nonaccrual status. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5111-111524 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 16 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -URI http://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.1) -URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707 + Details
Name: | us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 35 -URI http://asc.fasb.org/extlink&oid=121611835&loc=SL49126937-111524 + Details
Name: | us-gaap_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Change in carrying amount of other real estate not separately disclosed. The change includes for example, but is not limited to, additions, improvements, disposals and valuation adjustments. + References No definition available. + Details
Name: | us-gaap_OtherRealEstatePeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnusualRiskOrUncertaintyByNatureAxis=func_CovidNineteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=func_CoronavirusAidReliefAndEconomicSecurityActMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=func_NewAppraisalProcessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | us-gaap_LoanRestructuringModificationAxis=func_TroubledDebtRestructuringMember
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_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
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: |

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

X
- Details
Name: | srt_StatementScenarioAxis=func_DelayInPreparationOfForbearanceAgreementMember
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_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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