<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.21.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>468</ContextCount>
  <ElementCount>333</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>65</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000010 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>000020 - Statement - CONSOLIDATED BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_StatementConsolidatedBalanceSheets</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>000030 - Statement - CONSOLIDATED BALANCE SHEETS - Parenthetical</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>CONSOLIDATED BALANCE SHEETS - Parenthetical</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>000040 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_StatementConsolidatedStatementsOfOperations</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF OPERATIONS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>000050 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_StatementConsolidatedStatementsOfStockholdersEquity</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>000060 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>CONSOLIDATED STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>000070 - Disclosure - 1. Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>000080 - Disclosure - 2. Net Loss Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure2NetLossPerShare</Role>
      <ShortName>2. Net Loss Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>000090 - Disclosure - 3.Changes in Accumulated Other Comprehensive Loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure3ChangesInAccumulatedOtherComprehensiveLoss</Role>
      <ShortName>3.Changes in Accumulated Other Comprehensive Loss</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>000100 - Disclosure - 4. New Authoritative Accounting Guidance</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure4NewAuthoritativeAccountingGuidance</Role>
      <ShortName>4. New Authoritative Accounting Guidance</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>000110 - Disclosure - 5. Investment Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecurities</Role>
      <ShortName>5. Investment Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>000120 - Disclosure - 6. Loans and Allowance for Loan Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLosses</Role>
      <ShortName>6. Loans and Allowance for Loan Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>000130 - Disclosure - 7. Other Real Estate Owned</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwned</Role>
      <ShortName>7. Other Real Estate Owned</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>000140 - Disclosure - 8. Fair Value</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValue</Role>
      <ShortName>8. Fair Value</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>000150 - Disclosure - 9. Revenue Recognition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure9RevenueRecognition</Role>
      <ShortName>9. Revenue Recognition</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>000160 - Disclosure - 10. Regulatory</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure10Regulatory</Role>
      <ShortName>10. Regulatory</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>000170 - Disclosure - 11. Going Concern</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure11GoingConcern</Role>
      <ShortName>11. Going Concern</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>000180 - Disclosure - 12. Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure12SubsequentEvents</Role>
      <ShortName>12. Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>000190 - Disclosure - 1. Summary of Significant Accounting Policies: Management's Use of Estimates (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesManagementSUseOfEstimatesPolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Management's Use of Estimates (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>000200 - Disclosure - 1. Summary of Significant Accounting Policies: Commitments and Contingencies, Policy (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesCommitmentsAndContingenciesPolicyPolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Commitments and Contingencies, Policy (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>000210 - Disclosure - 1. Summary of Significant Accounting Policies: Loans Held For Sale (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesLoansHeldForSalePolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Loans Held For Sale (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>000220 - Disclosure - 1. Summary of Significant Accounting Policies: Loans Held At Fair Value (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesLoansHeldAtFairValuePolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Loans Held At Fair Value (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>000230 - Disclosure - 1. Summary of Significant Accounting Policies: Loans (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesLoansPolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Loans (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>000240 - Disclosure - 1. Summary of Significant Accounting Policies: Allowance For Loan Losses (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesAllowanceForLoanLossesPolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Allowance For Loan Losses (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>000250 - Disclosure - 1. Summary of Significant Accounting Policies: Non-accrual and Past Due Loans. (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesNonAccrualAndPastDueLoansPolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Non-accrual and Past Due Loans. (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>000260 - Disclosure - 1. Summary of Significant Accounting Policies: Income Taxes (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPoliciesIncomeTaxesPolicies</Role>
      <ShortName>1. Summary of Significant Accounting Policies: Income Taxes (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>000270 - Disclosure - 4. New Authoritative Accounting Guidance: New Accounting Pronouncements, Policy (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure4NewAuthoritativeAccountingGuidanceNewAccountingPronouncementsPolicyPolicies</Role>
      <ShortName>4. New Authoritative Accounting Guidance: New Accounting Pronouncements, Policy (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure1SummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>000280 - Disclosure - 2. Net Loss Per Share: Schedule of Net Loss per Common Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure2NetLossPerShareScheduleOfNetLossPerCommonShareTables</Role>
      <ShortName>2. Net Loss Per Share: Schedule of Net Loss per Common Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>000290 - Disclosure - 3.Changes in Accumulated Other Comprehensive Loss: Schedule of Components of Other Comprehensive Loss (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure3ChangesInAccumulatedOtherComprehensiveLossScheduleOfComponentsOfOtherComprehensiveLossTables</Role>
      <ShortName>3.Changes in Accumulated Other Comprehensive Loss: Schedule of Components of Other Comprehensive Loss (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>000300 - Disclosure - 5. Investment Securities: Schedule of Available-for-sale Securities Reconciliation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfAvailableForSaleSecuritiesReconciliationTables</Role>
      <ShortName>5. Investment Securities: Schedule of Available-for-sale Securities Reconciliation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>000310 - Disclosure - 5. Investment Securities: Schedule of Investments Classified by Contractual Maturity Date (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfInvestmentsClassifiedByContractualMaturityDateTables</Role>
      <ShortName>5. Investment Securities: Schedule of Investments Classified by Contractual Maturity Date (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>000320 - Disclosure - 5. Investment Securities: Schedule of Continuous Unrealized Loss Positions on Held-To-Maturity Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfContinuousUnrealizedLossPositionsOnHeldToMaturityInvestmentsTables</Role>
      <ShortName>5. Investment Securities: Schedule of Continuous Unrealized Loss Positions on Held-To-Maturity Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>000330 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Accounts, Notes, Loans and Financing Receivable (Tables)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfAccountsNotesLoansAndFinancingReceivableTables</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Accounts, Notes, Loans and Financing Receivable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>000340 - Disclosure - 6. Loans and Allowance for Loan Losses: Financing Receivable, Allowance for Credit Loss (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesFinancingReceivableAllowanceForCreditLossTables</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Financing Receivable, Allowance for Credit Loss (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>000350 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Age Analysis of Past Due Loans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfAgeAnalysisOfPastDueLoansTables</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Age Analysis of Past Due Loans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>000360 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Bank Loans by Class According to Credit Quality (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfBankLoansByClassAccordingToCreditQualityTables</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Bank Loans by Class According to Credit Quality (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>000370 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Impaired Loans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfImpairedLoansTables</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Impaired Loans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>000380 - Disclosure - 7. Other Real Estate Owned: Other Real Estate, Roll Forward (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedOtherRealEstateRollForwardTables</Role>
      <ShortName>7. Other Real Estate Owned: Other Real Estate, Roll Forward (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>000390 - Disclosure - 7. Other Real Estate Owned: Schedule of Components Of Other Real Estate Owned (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedScheduleOfComponentsOfOtherRealEstateOwnedTables</Role>
      <ShortName>7. Other Real Estate Owned: Schedule of Components Of Other Real Estate Owned (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>000400 - Disclosure - 7. Other Real Estate Owned: Components Of Net Expense Of Other Real Estate (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedComponentsOfNetExpenseOfOtherRealEstateTables</Role>
      <ShortName>7. Other Real Estate Owned: Components Of Net Expense Of Other Real Estate (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>000410 - Disclosure - 8. Fair Value: Fair Value, Assets Measured on Recurring Basis (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueAssetsMeasuredOnRecurringBasisTables</Role>
      <ShortName>8. Fair Value: Fair Value, Assets Measured on Recurring Basis (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>000420 - Disclosure - 8. Fair Value: Fair Value Measurement Inputs and Valuation Techniques (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueMeasurementInputsAndValuationTechniquesTables</Role>
      <ShortName>8. Fair Value: Fair Value Measurement Inputs and Valuation Techniques (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>000430 - Disclosure - 8. Fair Value: Fair Value Measurements, Nonrecurring (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueMeasurementsNonrecurringTables</Role>
      <ShortName>8. Fair Value: Fair Value Measurements, Nonrecurring (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>000440 - Disclosure - 8. Fair Value: Fair Value, by Balance Sheet Grouping (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueByBalanceSheetGroupingTables</Role>
      <ShortName>8. Fair Value: Fair Value, by Balance Sheet Grouping (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>000450 - Disclosure - 9. Revenue Recognition: Noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606 (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure9RevenueRecognitionNoninterestIncomeSegregatedByRevenueStreamsInScopeAndOutOfScopeOfTopic606Tables</Role>
      <ShortName>9. Revenue Recognition: Noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606 (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>000460 - Disclosure - 2. Net Loss Per Share: Schedule of Net Loss per Common Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure2NetLossPerShareScheduleOfNetLossPerCommonShareDetails</Role>
      <ShortName>2. Net Loss Per Share: Schedule of Net Loss per Common Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure2NetLossPerShareScheduleOfNetLossPerCommonShareTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>000470 - Disclosure - 3.Changes in Accumulated Other Comprehensive Loss: Schedule of Components of Other Comprehensive Loss (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure3ChangesInAccumulatedOtherComprehensiveLossScheduleOfComponentsOfOtherComprehensiveLossDetails</Role>
      <ShortName>3.Changes in Accumulated Other Comprehensive Loss: Schedule of Components of Other Comprehensive Loss (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure3ChangesInAccumulatedOtherComprehensiveLossScheduleOfComponentsOfOtherComprehensiveLossTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>000480 - Disclosure - 5. Investment Securities: Schedule of Available-for-sale Securities Reconciliation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfAvailableForSaleSecuritiesReconciliationDetails</Role>
      <ShortName>5. Investment Securities: Schedule of Available-for-sale Securities Reconciliation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfAvailableForSaleSecuritiesReconciliationTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>000490 - Disclosure - 5. Investment Securities: Schedule of Investments Classified by Contractual Maturity Date (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfInvestmentsClassifiedByContractualMaturityDateDetails</Role>
      <ShortName>5. Investment Securities: Schedule of Investments Classified by Contractual Maturity Date (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfInvestmentsClassifiedByContractualMaturityDateTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>000500 - Disclosure - 5. Investment Securities: Schedule of Continuous Unrealized Loss Positions on Held-To-Maturity Investments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfContinuousUnrealizedLossPositionsOnHeldToMaturityInvestmentsDetails</Role>
      <ShortName>5. Investment Securities: Schedule of Continuous Unrealized Loss Positions on Held-To-Maturity Investments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfContinuousUnrealizedLossPositionsOnHeldToMaturityInvestmentsTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>000510 - Disclosure - 5. Investment Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesDetails</Role>
      <ShortName>5. Investment Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure5InvestmentSecuritiesScheduleOfAvailableForSaleSecuritiesReconciliationTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>000520 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Accounts, Notes, Loans and Financing Receivable (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfAccountsNotesLoansAndFinancingReceivableDetails</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Accounts, Notes, Loans and Financing Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfAccountsNotesLoansAndFinancingReceivableTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>000530 - Disclosure - 6. Loans and Allowance for Loan Losses: Financing Receivable, Allowance for Credit Loss (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesFinancingReceivableAllowanceForCreditLossDetails</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Financing Receivable, Allowance for Credit Loss (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesFinancingReceivableAllowanceForCreditLossTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>000540 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Age Analysis of Past Due Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfAgeAnalysisOfPastDueLoansDetails</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Age Analysis of Past Due Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfAgeAnalysisOfPastDueLoansTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>000550 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Bank Loans by Class According to Credit Quality (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfBankLoansByClassAccordingToCreditQualityDetails</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Bank Loans by Class According to Credit Quality (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfBankLoansByClassAccordingToCreditQualityTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>000560 - Disclosure - 6. Loans and Allowance for Loan Losses: Schedule of Impaired Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfImpairedLoansDetails</Role>
      <ShortName>6. Loans and Allowance for Loan Losses: Schedule of Impaired Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure6LoansAndAllowanceForLoanLossesScheduleOfImpairedLoansTables</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>000570 - Disclosure - 7. Other Real Estate Owned: Other Real Estate, Roll Forward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedOtherRealEstateRollForwardDetails</Role>
      <ShortName>7. Other Real Estate Owned: Other Real Estate, Roll Forward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedOtherRealEstateRollForwardTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>000580 - Disclosure - 7. Other Real Estate Owned: Schedule of Components Of Other Real Estate Owned (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedScheduleOfComponentsOfOtherRealEstateOwnedDetails</Role>
      <ShortName>7. Other Real Estate Owned: Schedule of Components Of Other Real Estate Owned (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedScheduleOfComponentsOfOtherRealEstateOwnedTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>000590 - Disclosure - 7. Other Real Estate Owned: Components Of Net Expense Of Other Real Estate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedComponentsOfNetExpenseOfOtherRealEstateDetails</Role>
      <ShortName>7. Other Real Estate Owned: Components Of Net Expense Of Other Real Estate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure7OtherRealEstateOwnedComponentsOfNetExpenseOfOtherRealEstateTables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>000600 - Disclosure - 8. Fair Value: Fair Value, Assets Measured on Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueAssetsMeasuredOnRecurringBasisDetails</Role>
      <ShortName>8. Fair Value: Fair Value, Assets Measured on Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueAssetsMeasuredOnRecurringBasisTables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>000610 - Disclosure - 8. Fair Value: Fair Value Measurement Inputs and Valuation Techniques (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueMeasurementInputsAndValuationTechniquesDetails</Role>
      <ShortName>8. Fair Value: Fair Value Measurement Inputs and Valuation Techniques (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueMeasurementInputsAndValuationTechniquesTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>000620 - Disclosure - 8. Fair Value: Fair Value Measurements, Nonrecurring (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueMeasurementsNonrecurringDetails</Role>
      <ShortName>8. Fair Value: Fair Value Measurements, Nonrecurring (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueMeasurementsNonrecurringTables</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>000630 - Disclosure - 8. Fair Value: Fair Value, by Balance Sheet Grouping (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueByBalanceSheetGroupingDetails</Role>
      <ShortName>8. Fair Value: Fair Value, by Balance Sheet Grouping (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure8FairValueFairValueByBalanceSheetGroupingTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>000640 - Disclosure - 9. Revenue Recognition: Noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure9RevenueRecognitionNoninterestIncomeSegregatedByRevenueStreamsInScopeAndOutOfScopeOfTopic606Details</Role>
      <ShortName>9. Revenue Recognition: Noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure9RevenueRecognitionNoninterestIncomeSegregatedByRevenueStreamsInScopeAndOutOfScopeOfTopic606Tables</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>000650 - Disclosure - 10. Regulatory (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure10RegulatoryDetails</Role>
      <ShortName>10. Regulatory (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure10Regulatory</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="usbi-20180331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>000660 - Disclosure - 11. Going Concern (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://ubsiinc.com/20180331/role/idr_Disclosure11GoingConcernDetails</Role>
      <ShortName>11. Going Concern (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://ubsiinc.com/20180331/role/idr_Disclosure11GoingConcern</ParentRole>
      <Position>66</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q/A" original="usbi-20180331.htm">usbi-20180331.htm</File>
    <File>usbi-20180331.xsd</File>
    <File>usbi-20180331_cal.xml</File>
    <File>usbi-20180331_def.xml</File>
    <File>usbi-20180331_lab.xml</File>
    <File>usbi-20180331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2021</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2021-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2021-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
