$UBFO
UNITED SECURITY BANCSHARES Stock $ubfo

$ubfo Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000113754721000004 Filed on March 05, 2021

Income Statement

Concept	2020 Q4	2020 Q3	2020 Q2
Revenue	$9.041M	$8.098M	$8.243M
YoY Change	-10.82%	-22.26%	-20.05%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$370.0K	$340.0K	$360.0K
YoY Change	8.82%	-8.11%	9.09%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$499.0K	$500.0K	$530.0K
YoY Change	-42.11%	-52.87%	-47.42%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$2.573M	$3.165M	$2.810M
YoY Change	-35.72%	-46.07%	-51.27%
Income Tax	$651.0K	$894.0K	$798.0K
% Of Pretax Income	25.3%	28.25%	28.4%
Net Earnings	$1.924M	$2.271M	$2.012M
YoY Change	-33.54%	-45.58%	-50.89%
Net Earnings / Revenue	21.28%	28.04%	24.41%
Basic Earnings Per Share	$0.11	$0.13	$0.12
Diluted Earnings Per Share	$0.11	$0.13	$0.12
COMMON SHARES
Basic Shares Outstanding		16.98M shares	16.98M shares
Diluted Shares Outstanding		17.00M shares	16.99M shares

Balance Sheet

Concept	2020 Q4	2020 Q3	2020 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$294.1M	$323.3M	$229.5M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$12.00M	$12.30M	$12.50M
YoY Change	27.93%	30.09%	31.18%
Goodwill	$4.488M	$4.488M	$4.488M
YoY Change	0.0%	0.0%	0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$2.900M	$2.600M	$2.600M
YoY Change	-9.38%	-16.13%	-16.13%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$1.093B	$1.134B	$1.031B
YoY Change	14.18%	18.44%	2.47%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable		$0.00	$0.00
YoY Change		-100.0%	-100.0%
Accrued Expenses	$3.000M	$3.000M	$3.200M
YoY Change	-14.29%	-18.92%	-17.95%
Deferred Revenue
YoY Change
Short-Term Debt
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$3.000M	$3.000M	$3.200M
YoY Change	-16.67%	-21.05%	-20.0%
LONG-TERM LIABILITIES
Long-Term Debt	$10.90M	$10.10M	$9.800M
YoY Change	0.93%	-1.94%	-6.67%
Other Long-Term Liabilities	$8.305M	$8.000M	$7.800M
YoY Change	1.28%	2.56%	1.3%
Total Long-Term Liabilities	$8.305M	$18.10M	$17.60M
YoY Change	-56.29%	0.0%	-3.3%
TOTAL LIABILITIES
Total Short-Term Liabilities	$3.000M	$3.000M	$3.200M
Total Long-Term Liabilities	$8.305M	$18.10M	$17.60M
Total Liabilities	$974.8M	$1.016B	$913.9M
YoY Change	15.92%	20.63%	2.32%
SHAREHOLDERS EQUITY
Retained Earnings	$59.14M	$59.08M	$58.68M
YoY Change	2.59%	4.35%	8.04%
Common Stock	$59.40M	$59.29M	$59.18M
YoY Change	0.72%	0.67%	0.62%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$117.8M	$118.1M	$117.5M
YoY Change
Total Liabilities & Shareholders Equity	$1.093B	$1.134B	$1.031B
YoY Change	14.18%	18.44%	2.47%

Cashflow Statement

Concept	2020 Q4	2020 Q3	2020 Q2
OPERATING ACTIVITIES
Net Income	$1.924M	$2.271M	$2.012M
YoY Change	-33.54%	-45.58%	-50.89%
Depreciation, Depletion And Amortization	$370.0K	$340.0K	$360.0K
YoY Change	8.82%	-8.11%	9.09%
Cash From Operating Activities	$4.430M	$1.250M	$3.310M
YoY Change	-2.21%	-73.35%	46.46%
INVESTING ACTIVITIES
Capital Expenditures	-$100.0K	-$280.0K	-$520.0K
YoY Change	-64.29%	-3.45%	85.71%
Acquisitions
YoY Change
Other Investing Activities	$10.39M	-$6.970M	-$23.91M
YoY Change	-137.8%	-54.59%	-356.82%
Cash From Investing Activities	$10.30M	-$7.270M	-$24.42M
YoY Change	-137.12%	-53.55%	-370.43%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-44.00M	99.81M	50.80M
YoY Change	1079.62%	-289.93%	35.58%
NET CHANGE
Cash From Operating Activities	4.430M	1.250M	3.310M
Cash From Investing Activities	10.30M	-7.270M	-24.42M
Cash From Financing Activities	-44.00M	99.81M	50.80M
Net Change In Cash	-29.27M	93.79M	29.69M
YoY Change	8.61%	-247.68%	-39.11%
FREE CASH FLOW
Cash From Operating Activities	$4.430M	$1.250M	$3.310M
Capital Expenditures	-$100.0K	-$280.0K	-$520.0K
Free Cash Flow	$4.530M	$1.530M	$3.830M
YoY Change	-5.82%	-69.28%	50.79%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2020	dei	Entity Central Index Key EntityCentralIndexKey	0001137547
CY2020	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2020	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
CY2020	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2020	dei	Document Type DocumentType	10-K
CY2020	dei	Document Period End Date DocumentPeriodEndDate	2020-12-31
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	CA
CY2020	dei	Amendment Flag AmendmentFlag	false
CY2019Q1	us-gaap	Accounting Standards Update Extensible List AccountingStandardsUpdateExtensibleList	us-gaap:AccountingStandardsUpdate201602Member
CY2020	dei	Document Type DocumentType	10-K
CY2020	dei	Document Annual Report DocumentAnnualReport	true
CY2020	dei	Document Transition Report DocumentTransitionReport	false
CY2020	dei	Entity File Number EntityFileNumber	000-32987
CY2020	dei	Entity Registrant Name EntityRegistrantName	UNITED SECURITY BANCSHARES
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	91-2112732
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	2126 Inyo Street
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	Fresno
CY2020	dei	Entity Address State Or Province EntityAddressStateOrProvince	CA
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	93721
CY2020	dei	City Area Code CityAreaCode	559
CY2020	dei	Entity Shell Company EntityShellCompany	false
CY2020Q2	dei	Entity Public Float EntityPublicFloat	89199616	USD
CY2021Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	17010288	shares
CY2020	dei	Local Phone Number LocalPhoneNumber	248-4943
CY2020	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	No
CY2020	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2020	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2020	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2020	dei	Entity Filer Category EntityFilerCategory	Non-accelerated Filer
CY2020	dei	Entity Small Business EntitySmallBusiness	true
CY2020	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2020Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	29490000	USD
CY2019Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	27291000	USD
CY2020Q4	ubfo	Due From Frb Interest Bearing Cash DueFromFrbInterestBearingCash	264579000	USD
CY2019Q4	ubfo	Due From Frb Interest Bearing Cash DueFromFrbInterestBearingCash	191704000	USD
CY2019Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	9380000	USD
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CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	82341000	USD
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CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	3851000	USD
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CY2019Q4	us-gaap	Short Term Investments ShortTermInvestments	80088000	USD
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CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	7908000	USD
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CY2020Q4	us-gaap	Interest Receivable InterestReceivable	8164000	USD
CY2019Q4	us-gaap	Interest Receivable InterestReceivable	8208000	USD
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CY2019Q4	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	6753000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	4488000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	4488000	USD
CY2020Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	2907000	USD
CY2019Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	3191000	USD
CY2020Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	20715000	USD
CY2019Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	20955000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	2864000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	3360000	USD
CY2020Q4	us-gaap	Other Assets OtherAssets	13316000	USD
CY2019Q4	us-gaap	Other Assets OtherAssets	12855000	USD
CY2020Q4	us-gaap	Assets Assets	1092654000	USD
CY2019Q4	us-gaap	Assets Assets	956919000	USD
CY2020Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	391897000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	311950000	USD
CY2020Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	560754000	USD
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CY2019Q4	us-gaap	Deposits Deposits	818362000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	2967000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	3463000	USD
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CY2020	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	1433000	USD
CY2019	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	1797000	USD
CY2020	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	730000	USD
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CY2020	ubfo	Gain Losson Fair Value Optionof Financial Liability GainLossonFairValueOptionofFinancialLiability	970000	USD
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CY2019	us-gaap	Noninterest Income NoninterestIncome	5754000	USD
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CY2020	us-gaap	Occupancy Net OccupancyNet	3475000	USD
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CY2020	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	493000	USD
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CY2020	us-gaap	Professional Fees ProfessionalFees	3217000	USD
CY2019	us-gaap	Professional Fees ProfessionalFees	3760000	USD
CY2020	ubfo	Regulatory Assessments Expense Benefit RegulatoryAssessmentsExpenseBenefit	459000	USD
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CY2020	us-gaap	Noninterest Expense Directors Fees NoninterestExpenseDirectorsFees	376000	USD
CY2019	us-gaap	Noninterest Expense Directors Fees NoninterestExpenseDirectorsFees	373000	USD
CY2020	ubfo	Correspondent Bank Service Charges CorrespondentBankServiceCharges	71000	USD
CY2019	ubfo	Correspondent Bank Service Charges CorrespondentBankServiceCharges	57000	USD
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CY2020	us-gaap	Noninterest Expense NoninterestExpense	22160000	USD
CY2019	us-gaap	Noninterest Expense NoninterestExpense	21859000	USD
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CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.53
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CY2020	us-gaap	Net Income Loss NetIncomeLoss	8961000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	15172000	USD
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CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-135000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-307000	USD
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CY2019	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodBeforeTax	-1826000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Before Tax Portion Attributable To Parent OtherComprehensiveIncomeLossBeforeTaxPortionAttributableToParent	-136000	USD
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CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	338000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	82000	USD
CY2020	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-40000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-91000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	-338000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	-539000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-96000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1306000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	8865000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	13866000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	109240000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1306000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.33
CY2019	us-gaap	Dividends Common Stock Stock DividendsCommonStockStock	2870000	USD
CY2019Q4	us-gaap	Dividends Payable Amount Per Share DividendsPayableAmountPerShare	0.11
CY2019	us-gaap	Dividends Common Stock DividendsCommonStock	1182000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	349000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	15172000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	115988000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-96000	USD
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.33
CY2020	us-gaap	Dividends Common Stock Stock DividendsCommonStockStock	5600000	USD
CY2020Q4	us-gaap	Dividends Payable Amount Per Share DividendsPayableAmountPerShare	0.11
CY2020	us-gaap	Dividends Common Stock DividendsCommonStock	1870000	USD
CY2020	ubfo	Stockholders Equity Tax Benefit From Restricted Stock Units Released StockholdersEquityTaxBenefitFromRestrictedStockUnitsReleased	1000	USD
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	425000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	8961000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	117807000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	8961000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	15172000	USD
CY2020	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	2769000	USD
CY2019	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	20000	USD
CY2020	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	1411000	USD
CY2019	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	1402000	USD
CY2020	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	-600000	USD
CY2019	us-gaap	Operating Lease Right Of Use Asset Amortization Expense OperatingLeaseRightOfUseAssetAmortizationExpense	-741000	USD
CY2020	ubfo	Amortizationof Investment Securities AmortizationofInvestmentSecurities	1073000	USD
CY2019	ubfo	Amortizationof Investment Securities AmortizationofInvestmentSecurities	713000	USD
CY2020	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-44000	USD
CY2019	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	-133000	USD
CY2020	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	-27000	USD
CY2019	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	2000	USD
CY2020	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	244000	USD
CY2019	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	701000	USD
CY2020	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-367000	USD
CY2019	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	337000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	425000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	349000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	324000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	533000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-160000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	212000	USD
CY2020	us-gaap	Gain Loss On Sale Of Other Investments GainLossOnSaleOfOtherInvestments	0	USD
CY2019	us-gaap	Gain Loss On Sale Of Other Investments GainLossOnSaleOfOtherInvestments	-115000	USD
CY2020	us-gaap	Impairment Of Real Estate ImpairmentOfRealEstate	727000	USD
CY2019	us-gaap	Impairment Of Real Estate ImpairmentOfRealEstate	0	USD
CY2020	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	-113000	USD
CY2019	us-gaap	Gains Losses On Sales Of Other Real Estate GainsLossesOnSalesOfOtherRealEstate	0	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	74000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	117000	USD
CY2020	ubfo	Gain Loss On Fair Value Of Financial Instruments Net Pretax GainLossOnFairValueOfFinancialInstrumentsNetPretax	970000	USD
CY2019	ubfo	Gain Loss On Fair Value Of Financial Instruments Net Pretax GainLossOnFairValueOfFinancialInstrumentsNetPretax	1165000	USD
CY2020	us-gaap	Gain Loss On Sale Of Insurance Block GainLossOnSaleOfInsuranceBlock	310000	USD
CY2019	us-gaap	Gain Loss On Sale Of Insurance Block GainLossOnSaleOfInsuranceBlock	0	USD
CY2020	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	504000	USD
CY2019	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	528000	USD
CY2020	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	0	USD
CY2019	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	1000	USD
CY2020	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	13000	USD
CY2019	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	303000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	13800000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	16160000	USD
CY2020	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	45000	USD
CY2019	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	52000	USD
CY2020	ubfo	Principal Paymentsof Availablefor Sale Securities PrincipalPaymentsofAvailableforSaleSecurities	23055000	USD
CY2019	ubfo	Principal Paymentsof Availablefor Sale Securities PrincipalPaymentsofAvailableforSaleSecurities	17510000	USD
CY2020	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	29016000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	27830000	USD
CY2020	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	220000	USD
CY2019	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	220000	USD
CY2020	us-gaap	Payments To Acquire Loans And Leases Held For Investment PaymentsToAcquireLoansAndLeasesHeldForInvestment	60192000	USD
CY2019	us-gaap	Payments To Acquire Loans And Leases Held For Investment PaymentsToAcquireLoansAndLeasesHeldForInvestment	10956000	USD
CY2020	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	909000	USD
CY2019	us-gaap	Proceeds From Sale Of Other Real Estate ProceedsFromSaleOfOtherRealEstate	0	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	0	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	12000	USD
CY2020	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1243000	USD
CY2019	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1141000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	956000	USD
CY2020	us-gaap	Payments To Acquire Limited Partnership Interests PaymentsToAcquireLimitedPartnershipInterests	140000	USD
CY2019	us-gaap	Payments To Acquire Limited Partnership Interests PaymentsToAcquireLimitedPartnershipInterests	271000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-65547000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-22763000	USD
CY2020	us-gaap	Increase Decrease In Other Deposits IncreaseDecreaseInOtherDeposits	138171000	USD
CY2019	us-gaap	Increase Decrease In Other Deposits IncreaseDecreaseInOtherDeposits	29751000	USD
CY2020	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	-3882000	USD
CY2019	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	-17032000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	7468000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	7458000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	126821000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	5261000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	75074000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-1342000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	218995000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	220337000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	294069000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	218995000	USD
CY2020	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	segment
CY2020Q4	ubfo	Number Of Branches NumberOfBranches	12	branch
CY2020Q4	ubfo	Number Of Construction Lending Offices NumberOfConstructionLendingOffices	1	office
CY2020Q4	ubfo	Number Of Construction Lending Offices NumberOfConstructionLendingOffices	1	office
CY2020Q4	ubfo	Number Of Construction Lending Offices NumberOfConstructionLendingOffices	1	office
CY2020Q4	us-gaap	Real Estate Investments RealEstateInvestments	250000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates in the Preparation of Financial Statements</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> - The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.</span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%"> </span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses, goodwill, fair value of junior subordinated debt and certain collateralized mortgage obligations, and the valuation of real estate acquired in connection with foreclosures or in satisfaction of loans.</span></div>
CY2020Q4	us-gaap	Goodwill Goodwill	4500000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	425000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	349000	USD
CY2020	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:400;line-height:120%;padding-left:11.61pt">Reclassifications - </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Certain reclassifications have been made to prior year financial statements to conform to the classifications used in 2020. None of the reclassifications had an impact on equity or net income.</span>
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	81448000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	1134000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	241000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	82341000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	76561000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	272000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	521000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	76312000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
CY2019	us-gaap	Debt Securities Available For Sale Realized Loss DebtSecuritiesAvailableForSaleRealizedLoss	0	USD
CY2020	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale	0	USD
CY2019	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	0	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	491000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	489000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	17301000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	17451000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	25924000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	25956000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	37732000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	199000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	38445000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	81448000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	82341000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	9043000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	74000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	18647000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	167000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	27690000	USD
CY2020Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	241000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	29361000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	27233000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	322000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	56594000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	521000	USD
CY2020	ubfo	Number Of General Segments For The Segregation Of Portfolio NumberOfGeneralSegmentsForTheSegregationOfPortfolio	2	segment
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	117000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	74000	USD
CY2019Q4	us-gaap	Trading Securities TradingSecurities	0	USD
CY2020Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	0	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	655411000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	597374000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1093000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	7408000	USD
CY2020	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	4950000	USD
CY2019	us-gaap	Loans And Leases Receivable Related Parties Additions LoansAndLeasesReceivableRelatedPartiesAdditions	2675000	USD
CY2020	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	4143000	USD
CY2019	us-gaap	Loans And Leases Receivable Related Parties Proceeds LoansAndLeasesReceivableRelatedPartiesProceeds	8990000	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1900000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Related Parties LoansAndLeasesReceivableRelatedParties	1093000	USD
CY2020	us-gaap	Loans And Leases Receivable Commitments Fixed Rates LoansAndLeasesReceivableCommitmentsFixedRates	21000000	USD
CY2019	us-gaap	Loans And Leases Receivable Commitments Fixed Rates LoansAndLeasesReceivableCommitmentsFixedRates	12000000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	11126000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	644285000	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	655411000	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	513000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	12355000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	585019000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	597374000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	386000	USD
CY2020	ubfo	Period Of Default Minimum PeriodOfDefaultMinimum	P90D
CY2020	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	399000	USD
CY2020	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Accrual Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod	6000	USD
CY2020	ubfo	Number Of Monthly Payments To Demonstrate Repayment Ability NumberOfMonthlyPaymentsToDemonstrateRepaymentAbility	6	payment
CY2020	ubfo	Period Of Default Minimum PeriodOfDefaultMinimum	P90D
CY2020	ubfo	Contractually Past Due Days ContractuallyPastDueDays	P120D
CY2019	ubfo	Financing Receivable Remaining Undisbursed Commitments Loan Funds FinancingReceivableRemainingUndisbursedCommitmentsLoanFunds	0	USD
CY2020	ubfo	Financing Receivable Remaining Undisbursed Commitments Loan Funds FinancingReceivableRemainingUndisbursedCommitmentsLoanFunds	0	USD
CY2020Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	11496000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	11697000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	13370000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	12694000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	682000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	13376000	USD
CY2020Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	209000	USD
CY2020	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	15374000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	17036000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	14064000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	3008000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	17072000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1145000	USD
CY2019	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	18125000	USD
CY2019	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	601000	USD
CY2019	us-gaap	Impaired Financing Receivable With Related Allowance Interest Income Accrual Method ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod	36000	USD
CY2019	ubfo	Financing Receivable Periodof Successful Payment History Usedfor Restructured Loan Accrual Status FinancingReceivablePeriodofSuccessfulPaymentHistoryUsedforRestructuredLoanAccrualStatus	P6M
CY2019	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	1	USD
CY2019	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	0	USD
CY2020	ubfo	Financing Receivable Modifications Numberof Contracts During Period2 FinancingReceivableModificationsNumberofContractsDuringPeriod2	1	contract
CY2020	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	179000	USD
CY2020	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	179000	USD
CY2020	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	contract
CY2020	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	5187000	USD
CY2020	ubfo	Financing Receivable Modifications Defaults FinancingReceivableModificationsDefaults	0	USD
CY2020	ubfo	Financing Receivable Modifications Additions FinancingReceivableModificationsAdditions	179000	USD
CY2020	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	1940000	USD
CY2020	ubfo	Financing Receivables Impaired Troubled Debt Restructuring Credit Losses Write Offs FinancingReceivablesImpairedTroubledDebtRestructuringCreditLossesWriteOffs	0	USD
CY2020Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	3426000	USD
CY2020Q4	ubfo	Financing Receivable Modification Allowance For Loan Losses FinancingReceivableModificationAllowanceForLoanLosses	209000	USD
CY2018Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	7059000	USD
CY2019	ubfo	Financing Receivable Modifications Defaults FinancingReceivableModificationsDefaults	0	USD
CY2019	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	1836000	USD
CY2019	ubfo	Financing Receivables Impaired Troubled Debt Restructuring Credit Losses Write Offs FinancingReceivablesImpairedTroubledDebtRestructuringCreditLossesWriteOffs	36000	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	5187000	USD
CY2019Q4	ubfo	Financing Receivable Modification Allowance For Loan Losses FinancingReceivableModificationAllowanceForLoanLosses	538000	USD
CY2020Q4	ubfo	Number Of Restructured Loans NumberOfRestructuredLoans	7	loan
CY2020Q4	ubfo	Total Restructured Loans TotalRestructuredLoans	3426000	USD
CY2019Q4	ubfo	Number Of Restructured Loans NumberOfRestructuredLoans	13	loan
CY2019Q4	ubfo	Total Restructured Loans TotalRestructuredLoans	5187000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	0	USD
CY2020Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	0	USD
CY2020	ubfo	Number Of Risk Rating Approaches NumberOfRiskRatingApproaches	2	rating
CY2020	ubfo	Numberof Loan Portfolio Segment NumberofLoanPortfolioSegment	10	segment
CY2020	ubfo	Numberof Loans Entity Experienced Losses NumberofLoansEntityExperiencedLosses	3	loan
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	7908000	USD
CY2020	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-2769000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2320000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	165000	USD
CY2020	us-gaap	Financing Receivable Allowance For Credit Losses Period Increase Decrease FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease	2155000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	8522000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	209000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	8313000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	8522000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	813000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	306000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	8395000	USD
CY2019	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	-20000	USD
CY2019	us-gaap	Financing Receivable Allowance For Credit Losses Period Increase Decrease FinancingReceivableAllowanceForCreditLossesPeriodIncreaseDecrease	507000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	7908000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	1145000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	6763000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	7908000	USD
CY2020Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	13376000	USD
CY2020Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	642035000	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	655411000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	17072000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	580302000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	597374000	USD
CY2020Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	27000000	USD
CY2019Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Before Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization	26208000	USD
CY2020Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	17890000	USD
CY2019Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	16828000	USD
CY2020Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	9110000	USD
CY2019Q4	us-gaap	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	9380000	USD
CY2020	us-gaap	Depreciation Depreciation	1411000	USD
CY2019	us-gaap	Depreciation Depreciation	1402000	USD
CY2020	ubfo	Equity Method Investment Financial Information Net Income Loss EquityMethodInvestmentFinancialInformationNetIncomeLoss	0	USD
CY2019	ubfo	Equity Method Investment Financial Information Net Income Loss EquityMethodInvestmentFinancialInformationNetIncomeLoss	0	USD
CY2020Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	391897000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities NoninterestBearingDepositLiabilities	311950000	USD
CY2020Q4	us-gaap	Deposits Money Market Deposits And Negotiable Order Of Withdrawal Now DepositsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNOW	402565000	USD
CY2019Q4	us-gaap	Deposits Money Market Deposits And Negotiable Order Of Withdrawal Now DepositsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNOW	360934000	USD
CY2020Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	96669000	USD
CY2019Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	80078000	USD
CY2020Q4	ubfo	Time Deposits Less Than250000 TimeDepositsLessThan250000	40303000	USD
CY2019Q4	ubfo	Time Deposits Less Than250000 TimeDepositsLessThan250000	44926000	USD
CY2020Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	21217000	USD
CY2019Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	20474000	USD
CY2020Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	560754000	USD
CY2019Q4	us-gaap	Interest Bearing Deposit Liabilities InterestBearingDepositLiabilities	506412000	USD
CY2020Q4	us-gaap	Deposits Deposits	952651000	USD
CY2019Q4	us-gaap	Deposits Deposits	818362000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	49253000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year One TimeDepositMaturitiesYearOne	46103000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	10577000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Two TimeDepositMaturitiesYearTwo	16563000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	1021000	USD
CY2019	us-gaap	Lease Cost LeaseCost	970000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Three TimeDepositMaturitiesYearThree	1617000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	184000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Four TimeDepositMaturitiesYearFour	882000	USD
CY2020Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	385000	USD
CY2019Q4	us-gaap	Time Deposit Maturities Year Five TimeDepositMaturitiesYearFive	135000	USD
CY2020Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	100000	USD
CY2019Q4	us-gaap	Time Deposit Maturities After Year Five TimeDepositMaturitiesAfterYearFive	100000	USD
CY2020Q4	us-gaap	Time Deposits TimeDeposits	61520000	USD
CY2019Q4	us-gaap	Time Deposits TimeDeposits	65400000	USD
CY2020Q4	ubfo	Deposit Overdrafts DepositOverdrafts	506000	USD
CY2019Q4	ubfo	Deposit Overdrafts DepositOverdrafts	230000	USD
CY2020Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	11192000	USD
CY2019Q4	us-gaap	Related Party Deposit Liabilities RelatedPartyDepositLiabilities	6809000	USD
CY2020Q4	us-gaap	Federal Home Loan Bank Advances Current FederalHomeLoanBankAdvancesCurrent	0	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Current FederalHomeLoanBankAdvancesCurrent	0	USD
CY2020	ubfo	Lessee Operating Lease Number Of Contracts LesseeOperatingLeaseNumberOfContracts	13	contract
CY2020	ubfo	Lessee Financing Lease Number Of Contracts LesseeFinancingLeaseNumberOfContracts	0	contract
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	764000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	765000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	0	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	0	USD
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	249000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	205000	USD
CY2020	us-gaap	Sublease Income SubleaseIncome	0	USD
CY2019	us-gaap	Sublease Income SubleaseIncome	0	USD
CY2020	us-gaap	Lease Cost LeaseCost	1013000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	764000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	741000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	104000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3944000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P5Y10M6D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P6Y4M9D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0516
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0515
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	665000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	675000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	674000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	513000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	333000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	2967000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	763000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	653000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	580000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	3440000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	473000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	663000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	661000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	501000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	826000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	4067000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	604000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	3463000	USD
CY2020	us-gaap	Fair Value Option Credit Risk Gains Losses On Assets FairValueOptionCreditRiskGainsLossesOnAssets	-174000	USD
CY2019	us-gaap	Fair Value Option Credit Risk Gains Losses On Assets FairValueOptionCreditRiskGainsLossesOnAssets	-661000	USD
CY2020	us-gaap	Fair Value Option Credit Risk Gains Losses On Assets FairValueOptionCreditRiskGainsLossesOnAssets	-174000	USD
CY2020	ubfo	Fair Value Option Credit Risk Gross Gainson Assets FairValueOptionCreditRiskGrossGainsonAssets	970000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodBeforeTax	-1144000	USD
CY2019	us-gaap	Fair Value Option Credit Risk Gains Losses On Assets FairValueOptionCreditRiskGainsLossesOnAssets	-661000	USD
CY2019	ubfo	Fair Value Option Credit Risk Losseson Assets Net Before Tax FairValueOptionCreditRiskLossesonAssetsNetBeforeTax	-1165000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodBeforeTax	-1826000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	2906000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards DeferredTaxAssetsTaxCreditCarryforwards	1837000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	1506000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits	1438000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	256000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	180000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	109000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	120000	USD
CY2020Q4	ubfo	Deferred Tax Assets Write Down On Other Real Estate Owned DeferredTaxAssetsWriteDownOnOtherRealEstateOwned	291000	USD
CY2019Q4	ubfo	Deferred Tax Assets Write Down On Other Real Estate Owned DeferredTaxAssetsWriteDownOnOtherRealEstateOwned	89000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	1353000	USD
CY2020Q4	ubfo	Deferred Tax Assets Unrealized Gainon Retirement Obligation DeferredTaxAssetsUnrealizedGainonRetirementObligation	325000	USD
CY2019Q4	ubfo	Deferred Tax Assets Unrealized Gainon Retirement Obligation DeferredTaxAssetsUnrealizedGainonRetirementObligation	285000	USD
CY2020Q4	ubfo	Deferred Tax Assets Unrealized Gain Losses On Treasury Preferred Securities DeferredTaxAssetsUnrealizedGainLossesOnTreasuryPreferredSecurities	246000	USD
CY2019Q4	ubfo	Deferred Tax Assets Unrealized Gain Losses On Treasury Preferred Securities DeferredTaxAssetsUnrealizedGainLossesOnTreasuryPreferredSecurities	-91000	USD
CY2020Q4	ubfo	Deferred Tax Asset Intereston Non Accrual Loans DeferredTaxAssetInterestonNonAccrualLoans	443000	USD
CY2019Q4	ubfo	Deferred Tax Asset Intereston Non Accrual Loans DeferredTaxAssetInterestonNonAccrualLoans	336000	USD
CY2020Q4	ubfo	Deferred Tax Assets Operating Lease Liability DeferredTaxAssetsOperatingLeaseLiability	875000	USD
CY2019Q4	ubfo	Deferred Tax Assets Operating Lease Liability DeferredTaxAssetsOperatingLeaseLiability	1021000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	467000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	1499000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	7424000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	6714000	USD
CY2020Q4	ubfo	Deferred Tax Liabilities State Tax DeferredTaxLiabilitiesStateTax	211000	USD
CY2019Q4	ubfo	Deferred Tax Liabilities State Tax DeferredTaxLiabilitiesStateTax	196000	USD
CY2020Q4	ubfo	Deferred Tax Liabilities Federal Home Loan Bank Dividend DeferredTaxLiabilitiesFederalHomeLoanBankDividend	46000	USD
CY2019Q4	ubfo	Deferred Tax Liabilities Federal Home Loan Bank Dividend DeferredTaxLiabilitiesFederalHomeLoanBankDividend	46000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	1014000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	771000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Tax Deferred Income DeferredTaxLiabilitiesTaxDeferredIncome	462000	USD
CY2020Q4	ubfo	Deferred Tax Liabilities Fair Value Adjustments For Purchase Accounting DeferredTaxLiabilitiesFairValueAdjustmentsForPurchaseAccounting	98000	USD
CY2019Q4	ubfo	Deferred Tax Liabilities Fair Value Adjustments For Purchase Accounting DeferredTaxLiabilitiesFairValueAdjustmentsForPurchaseAccounting	98000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	689000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Deferred Financing Costs DeferredTaxLiabilitiesDeferredExpenseDeferredFinancingCosts	548000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	239000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Prepaid Expenses DeferredTaxLiabilitiesPrepaidExpenses	241000	USD
CY2020Q4	ubfo	Deferred Tax Liabilities Unrealized Gains Losses On Available For Sale Securities DeferredTaxLiabilitiesUnrealizedGainsLossesOnAvailableForSaleSecurities	265000	USD
CY2019Q4	ubfo	Deferred Tax Liabilities Unrealized Gains Losses On Available For Sale Securities DeferredTaxLiabilitiesUnrealizedGainsLossesOnAvailableForSaleSecurities	-73000	USD
CY2020Q4	ubfo	Deferred Tax Liabilities Operating Right Of Use Asset DeferredTaxLiabilitiesOperatingRightOfUseAsset	845000	USD
CY2019Q4	ubfo	Deferred Tax Liabilities Operating Right Of Use Asset DeferredTaxLiabilitiesOperatingRightOfUseAsset	991000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	4517000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	3523000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	2907000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	3191000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	1871000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1256000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	3127000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	399000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-75000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	324000	USD
CY2020	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	2270000	USD
CY2020	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	1181000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3451000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	3627000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1937000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	5564000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	269000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	264000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	533000	USD
CY2019	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	3896000	USD
CY2019	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	2201000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6097000	USD
CY2020	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2019	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies State And Local EffectiveIncomeTaxRateReconciliationTaxContingenciesStateAndLocal	0.082
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies State And Local EffectiveIncomeTaxRateReconciliationTaxContingenciesStateAndLocal	0.083
CY2020	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.014
CY2019	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.006
CY2020	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.278
CY2019	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.287
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2020	ubfo	Sharebased Compensation Arrangementby Sharebased Payment Award Numberof Plans SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans	2	plan
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	94601	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	7.87
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	0	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	0
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CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	0
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	0	shares
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	0
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	94601	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	7.87
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber	70601	shares
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	7.10
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P4Y9M
CY2020Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	108000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	425000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	349000	USD
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions	147000	USD
CY2019Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions	226000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P6Y8M4D
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CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	0
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	86000	USD
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	90000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	0	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	0	USD
CY2020	us-gaap	Defined Contribution Plan Employers Matching Contribution Annual Vesting Percentage DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage	1
CY2020	us-gaap	Defined Contribution Plan Employer Matching Contribution Percent DefinedContributionPlanEmployerMatchingContributionPercent	0.04
CY2020	us-gaap	Defined Contribution Plan Employers Matching Contribution Annual Vesting Percentage DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage	1
CY2020	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	250000	USD
CY2020Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.0136
CY2019	us-gaap	Defined Benefit Plan Contributions By Employer DefinedBenefitPlanContributionsByEmployer	256000	USD
CY2020	ubfo	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Term DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationTerm	P20Y
CY2020Q4	ubfo	Salary Continuation Plan Accrued Liability SalaryContinuationPlanAccruedLiability	4731000	USD
CY2019Q4	ubfo	Salary Continuation Plan Accrued Liability SalaryContinuationPlanAccruedLiability	4516000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.0243
CY2020	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	284000	USD
CY2019	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	272000	USD
CY2020Q4	ubfo	Numberof Officers NumberofOfficers	3	Agreement
CY2020	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	30000	USD
CY2019	us-gaap	Postemployment Benefits Period Expense PostemploymentBenefitsPeriodExpense	37000	USD
CY2020	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Loss Net Gain Loss Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax	770000	USD
CY2019	us-gaap	Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Loss Net Gain Loss Before Tax DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax	675000	USD
CY2020Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	20715000	USD
CY2019Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	20955000	USD
CY2020	ubfo	Income Losson Bank Owned Life Insurance Policies IncomeLossonBankOwnedLifeInsurancePolicies	474000	USD
CY2019	ubfo	Income Losson Bank Owned Life Insurance Policies IncomeLossonBankOwnedLifeInsurancePolicies	491000	USD
CY2020	ubfo	Minimumtermofguarantees Minimumtermofguarantees	P1M
CY2020	ubfo	Maximum Term Of Guarantees MaximumTermOfGuarantees	P3Y
CY2020Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	94560000	USD
CY2020Q4	us-gaap	Liabilities Fair Value Disclosure LiabilitiesFairValueDisclosure	10924000	USD
CY2019Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	80232000	USD
CY2019Q4	us-gaap	Liabilities Fair Value Disclosure LiabilitiesFairValueDisclosure	10808000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	2316000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	3887000	USD
CY2020	us-gaap	Income Taxes Paid IncomeTaxesPaid	3443000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	5910000	USD
CY2020	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	0	USD
CY2019	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	1008000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodBeforeTax	-1144000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodBeforeTax	-1826000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	1143000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	279000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-135000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-307000	USD
CY2020	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	1870000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	1868000	USD
CY2020	ubfo	Right Of Use Assets And Liabilities RightOfUseAssetsAndLiabilities	104000	USD
CY2019	ubfo	Right Of Use Assets And Liabilities RightOfUseAssetsAndLiabilities	3944000	USD
CY2019Q1	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3502000	USD
CY2019Q1	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	3593000	USD
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2020Q1	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	1867000	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2020Q2	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	1866000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2020Q3	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	1867000	USD
CY2020Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2020Q4	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	1870000	USD
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.11
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	8961000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	15172000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16976704	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16951955	shares
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	21880	shares
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	32841	shares
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16998584	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16984796	shares
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.53
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.90
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.53
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.89
CY2020	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	72000	shares
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	60000	shares
CY2017Q4	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	3000000	USD
CY2019	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	0	shares
CY2020	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	0	shares
CY2020Q4	us-gaap	Goodwill Goodwill	4488000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	4488000	USD
CY2020	us-gaap	Number Of Reporting Units NumberOfReportingUnits	2	reporting_unit
CY2020Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	8580000	USD
CY2020Q4	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	8672000	USD
CY2020Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	7563000	USD
CY2020Q2	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	7713000	USD
CY2020Q1	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	8346000	USD
CY2020Q4	us-gaap	Interest Income Operating InterestIncomeOperating	369000	USD
CY2020Q3	us-gaap	Interest Income Operating InterestIncomeOperating	405000	USD
CY2020Q2	us-gaap	Interest Income Operating InterestIncomeOperating	394000	USD
CY2020Q1	us-gaap	Interest Income Operating InterestIncomeOperating	995000	USD
CY2020Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	9041000	USD
CY2020Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	7968000	USD
CY2020Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	8107000	USD
CY2020Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	9341000	USD
CY2020Q4	us-gaap	Interest Expense InterestExpense	499000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	500000	USD
CY2020Q2	us-gaap	Interest Expense InterestExpense	530000	USD
CY2020Q1	us-gaap	Interest Expense InterestExpense	761000	USD
CY2020Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	8542000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	7468000	USD
CY2020Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	7577000	USD
CY2020Q4	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	631000	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	4000	USD
CY2020Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	427000	USD
CY2020Q1	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	1707000	USD
CY2020Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	7911000	USD
CY2020Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	7464000	USD
CY2020Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	7150000	USD
CY2020Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	6873000	USD
CY2020Q4	us-gaap	Noninterest Income NoninterestIncome	467000	USD
CY2020Q3	us-gaap	Noninterest Income NoninterestIncome	911000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	1216000	USD
CY2020Q1	us-gaap	Noninterest Income NoninterestIncome	2580000	USD
CY2020Q4	us-gaap	Noninterest Expense NoninterestExpense	5805000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	5210000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	5554000	USD
CY2020Q1	us-gaap	Noninterest Expense NoninterestExpense	5591000	USD
CY2020Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	2573000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	3165000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	2812000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	3862000	USD
CY2020Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	651000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	894000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	798000	USD
CY2020Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1108000	USD
CY2020Q4	us-gaap	Net Income Loss NetIncomeLoss	1922000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	2271000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	2014000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	2754000	USD
CY2020Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.11
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.13
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.12
CY2020Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.16
CY2020Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.11
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.13
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.12
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.16
CY2019Q4	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	8872000	USD
CY2019Q3	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	8648000	USD
CY2019Q2	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	8443000	USD
CY2019Q1	us-gaap	Interest And Fee Income Loans And Leases InterestAndFeeIncomeLoansAndLeases	8642000	USD
CY2019Q4	us-gaap	Interest Income Operating InterestIncomeOperating	1266000	USD
CY2019Q3	us-gaap	Interest Income Operating InterestIncomeOperating	1769000	USD
CY2019Q2	us-gaap	Interest Income Operating InterestIncomeOperating	1867000	USD
CY2019Q1	us-gaap	Interest Income Operating InterestIncomeOperating	1775000	USD
CY2019Q4	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	10138000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	10417000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	10310000	USD
CY2019Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	10417000	USD
CY2019Q4	us-gaap	Interest Expense InterestExpense	862000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	1061000	USD
CY2019Q2	us-gaap	Interest Expense InterestExpense	1008000	USD
CY2019Q1	us-gaap	Interest Expense InterestExpense	957000	USD
CY2019Q4	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	9276000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	9356000	USD
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	9302000	USD
CY2019Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	9460000	USD
CY2019Q4	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	5000	USD
CY2019Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	5000	USD
CY2019Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	4000	USD
CY2019Q1	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	6000	USD
CY2019Q4	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	9271000	USD
CY2019Q3	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	9351000	USD
CY2019Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	9298000	USD
CY2019Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	9454000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	2895000	USD
CY2019Q4	us-gaap	Noninterest Income NoninterestIncome	647000	USD
CY2019Q3	us-gaap	Noninterest Income NoninterestIncome	1853000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	1731000	USD
CY2019Q1	us-gaap	Noninterest Income NoninterestIncome	1523000	USD
CY2019Q4	us-gaap	Noninterest Expense NoninterestExpense	5915000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	5335000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	5262000	USD
CY2019Q1	us-gaap	Noninterest Expense NoninterestExpense	5347000	USD
CY2019Q4	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	4003000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	5869000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	5767000	USD
CY2019Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	5630000	USD
CY2019Q4	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1108000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1696000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1670000	USD
CY2019Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1623000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	4173000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	4097000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	4007000	USD
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.17
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.25
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.24
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.24
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.17
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.25
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.24
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.24

Files In Submission

Name	View Source	Status
0001137547-21-000004-index-headers.html	Edgar Link	pending
0001137547-21-000004-index.html	Edgar Link	pending
0001137547-21-000004.txt	Edgar Link	pending
0001137547-21-000004-xbrl.zip	Edgar Link	pending
ex1013-executivesalarycont.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
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R99.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending
ubfo-20201231.htm	Edgar Link	pending
ubfo-20201231.xsd	Edgar Link	pending
ubfo-20201231exhibit211.htm	Edgar Link	pending
ubfo-20201231exhibit231.htm	Edgar Link	pending
ubfo-20201231exhibit311.htm	Edgar Link	pending
ubfo-20201231exhibit312.htm	Edgar Link	pending
ubfo-20201231exhibit321.htm	Edgar Link	pending
ubfo-20201231exhibit322.htm	Edgar Link	pending
ubfo-20201231_cal.xml	Edgar Link	unprocessable
ubfo-20201231_def.xml	Edgar Link	unprocessable
ubfo-20201231_htm.xml	Edgar Link	completed
ubfo-20201231_lab.xml	Edgar Link	unprocessable
ubfo-20201231_pre.xml	Edgar Link	unprocessable

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$UBFO
UNITED SECURITY BANCSHARES Stock $ubfo

2020 Q4 Form 10-K Financial Statement

#000113754721000004 Filed on March 05, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$UBFO UNITED SECURITY BANCSHARES Stock $ubfo

2020 Q4 Form 10-K Financial Statement

#000113754721000004 Filed on March 05, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$UBFO
UNITED SECURITY BANCSHARES Stock $ubfo