Document And Entity Information
Servicing Asset at Amortized Cost [Table Text Block]
Note To Financial Statement Details Textual
Significant Accounting Policies
Income tax expense
Income tax expense
Income Tax Expense (Benefit)
Note 3 - Investment Securities
Note 4 - Loans and Allowance for Credit Losses
Note 5 - Loan Servicing
Note 6 - Goodwill and Intangibles
Note 7 - Accrued Interest and Other Assets
Note 8 - Deposits
Remainder of 2026, 250,000 and under
Amount of time deposit $250,000 or less maturing in remaining fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Note 10 - Subordinated Debentures
Remainder of 2026, greater than 250,000
Amount of time deposit over $250,000, maturing in remainder of fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Nontaxable Municipal Bonds [Member]
Investment in Debt and Equity Securities and Other Trading Assets [Text Block]
The 2026 Repurchase Plan [Member]
Represents the 2026 Repurchase Plan.
Note 11 - Borrowing Arrangements
The 2025 and 2025 Share Repurchase Programs [Member]
Represents The 2025 and 2025 Share Repurchase Programs.
Note 13 - Commitments and Contingencies
O 2026 Q3 Dividends [Member]
Represents ordinary dividends in Q3 of 2026.
Note 14 - Leases
The 2025 Repurchase Plan [Member]
Represents the 2025 Repurchase Plan.
Note 16 - Stock-based Compensation
Note 17 - Regulatory Matters
Note 18 - Fair Value Measurements and Fair Value of Financial Instruments
Note 19 - Earnings Per Share
Advance With One Time Call, One Year Lock Out, Three [Member]
Advance With One Time Call, One Year Lock Out, Three
Note 20 - Revenue from Contracts with Customers
Single Reportable Segment [Member]
Single Reportable Segment
Note 21 - Segment Information
Advance With One Time Call, Six Month Lock Out, Two [Member]
Advance With One Time Call, Six Month Lock Out, Two
Advance With One Time Call, One Year Lock Out, Two [Member]
Advance With One Time Call, One Year Lock Out, Two
Note 3 - Investment Securities - Amortized Cost and Fair Value of Available for Sale Securities and Held to Maturity Securities (Details)
Note 3 - Investment Securities - Expected Maturities (Details)
Advance With One Time Call, Three Month Lock Out, Two [Member]
Advance With One Time Call, Three Month Lock Out, Two
Note 3 - Investment Securities - Summary of Investment Securities with Unrealized Losses (Details)
Note 4 - Loans and Allowance for Credit Losses - Schedule of Loans (Details)
Advance with No Call [Member]
Advance with No Call
Note 4 - Loans and Allowance for Credit Losses - Allowance for Loan Losses (Details)
Principal Reduction, Extended Maturity, and Interest Rate Reduction [Member]
Loan modification for extension of term of loan in which it must be paid, reduction of contractual interest rate, reduction of interest rate to lower than current market rate for new debt with similar risk, and reduction in principal.
Note 4 - Loans and Allowance for Credit Losses - Risk Category of Loans (Details)
Note 4 - Loans and Allowance for Credit Losses - Aging of Recorded Investment (Details)
Note 4 - Loans and Allowance for Credit Losses - Schedule of Financing Receivables, Nonaccrual Status (Details)
Note 4 - Loans and Allowance for Credit Losses - Schedule of Loans by Collateral Held (Details)
Basis of Presentation and Significant Accounting Policies [Text Block]
Note 4 - Loans and Allowance for Credit Losses - Loan Modifications (Details)
Note 5 - Loan Servicing - Schedule of Principal Balances of Mortgage and SBA Loans Serviced for Others (Details)
Note 5 - Loan Servicing - Schedule of Amortization of Mortgage Servicing Rights Netted Against Loan Servicing Fee Income (Details)
Note 6 - Goodwill and Intangibles - Maturity Schedule for Amortization Expense (Details)
Note 7 - Accrued Interest and Other Assets - Accrued Interest and Other Assets (Details)
Note 8 - Deposits - Schedule of Maturities of Time Deposits (Details)
Note 10 - Subordinated Debentures - Schedule of Subordinated Debentures (Details)
Note 11 - Borrowing Arrangements - Schedule of Borrowing Arrangements (Details)
Note 13 - Commitments and Contingencies - Schedule of Financial Commitments Represents Credit Risk (Details)
Note 14 - Leases - Future Minimum Rent Payments (Details)
Note 14 - Leases - Operating Lease (Details)
Note 16 - Stock-based Compensation - Summary of Awards Pursuant to Stock Option Plans (Details)
Note 16 - Stock-based Compensation - Restricted Stock Activity (Details)
Note 17 - Regulatory Matters - Summary of Company and Bank Continue to Exceed Regulatory Capital Minimum Requirements and Bank Continues to Exceed Well Capitalized Standards (Details)
Note 18 - Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Major Category of Assets and Liabilities (Details)
Note 18 - Fair Value Measurements and Fair Value of Financial Instruments - Measurement Inputs and Valuation Techniques (Details)
Note 18 - Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Fair Value Hierarchy Level and Estimated Fair Value of Significant Financial Instruments (Details)
Note 19 - Earnings Per Share - Reconciliation of Net Income and Shares Outstanding to Income and Number of Shares Used to Compute EPS (Details)
Note 20 - Revenue from Contracts with Customers - Summary of Revenue From Contracts With Customers In-scope and Not In-scope under Topic 606 (Details)
Note 21 - Segment Information - Schedule of Segment Information (Details)
Notes To Financial Statements
Salaries and benefits expense
Salaries and employee benefits
Notes To Financial Statements [Abstract]
Commercial and Industrial [Member]
Portfolio segment of the company's total financing receivables related to commercial and industrial receivables.
Segment Reporting [Text Block]
Segment Reporting [Table Text Block]
Preferred Stock - 100,000,000 shares authorized, no par value; none outstanding
us-gaap_Liabilities
Total liabilities
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and shareholders’ equity
Pledged Status [Domain]
Segment Reporting [Table]
Pledged Status [Axis]
Employee Retention Credit [Member]
Represents Employee Retention Credit.
Lessee, Lease, Description [Table]
Advance With Quarterly Call, One Year Lock Out [Member]
Represents advance with quarterly call, 1 year initial lock out.
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect
Net increase (decrease) in cash and cash equivalents
Servicing assets (1)
us-gaap_ServicingAssetAtFairValueAmount
Common Equity Tier 1 Risk-Based Capital Ratio, Ratio
Schedule of Fair Value, off-Balance-Sheet Risks [Table Text Block]
us-gaap_ServicingAssetAtAmortizedValueDisposals
Payoffs
Total Risk-Based Capital Ratio, Ratio
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash and cash equivalents at beginning of period
Cash and cash equivalents at end of period
Additions
US Government Agencies Debt Securities [Member]
us-gaap_ServicingAssetAtAmortizedValue
Beginning of period
End of period
Total Risk-Based Capital Ratio, Minimum Required for Capital Adequacy Purposes Ratio
Tier 1 Leverage Ratio, Ratio
us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Tier 1 Risk-Based Capital Ratio, Minimum Required for Capital Adequacy Purposes Ratio
Tier 1 Leverage Ratio, Minimum Required for Capital Adequacy Purposes Ratio
us-gaap_TimeDeposits
Time Deposits
Total
us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Line of Credit Facility, Current Borrowing Capacity
Tier 1 Risk-Based Capital Ratio, Ratio
Debt instrument, variable rate
Debt Instrument, Basis Spread on Variable Rate
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
Line of Credit Facility, Lender [Domain]
Financing Receivable, Allowance for Credit Loss [Table Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Outstanding (in shares)
Outstanding (in shares)
Lender Name [Axis]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Outstanding, weighted-average grant date fair value (in dollars per share)
Outstanding, weighted-average grant date fair value (in dollars per share)
Granted (1) (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)
Financing Receivable, Past Due [Table Text Block]
Granted, weighted-average grant date fair value (in dollars per share)
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Forfeited/cancelled (in shares)
Financing Receivable Credit Quality Indicators [Table Text Block]
Financing Receivable, Modified [Table Text Block]
Vested, weighted-average grant date fair value (in dollars per share)
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Vested (1) (in shares)
Collateralized Mortgage Obligations [Member]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Total future minimum lease payments
Weighted-average discount rate
Tenor Spread Adjustment [Member]
Represents the tenor spread adjustment.
Asset Class [Axis]
Commercial Real Estate [Member]
Financial commitments, contractual amount, fixed rate
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
2027, future minimum lease payments
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Forfeited/cancelled, shares (in shares)
Commercial Paper [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value
Loans
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)
us-gaap_OperatingLeaseExpense
Operating Lease, Expense
Gain (Loss) on Securities [Table Text Block]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear
Remainder of 2026, future minimum lease payments
Options exercisable, Shares (in shares)
us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend
Financing Receivable, Modified, Commitment to Lend
Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
Options exercisable, weighted average exercise price (in dollars per share)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
2029, future minimum lease payments
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Outstanding, shares (in shares)
Outstanding, shares (in shares)
Measurement Frequency [Axis]
rbb_PolicyTable
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
2028, future minimum lease payments
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Outstanding, weighted average exercise price (in dollars per share)
Outstanding, weighted average exercise price (in dollars per share)
Fair Value Hierarchy and NAV [Axis]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
2030, future minimum lease payments
Outstanding, Aggregate Intrinsic Value
Financial commitments, contractual amount, variable rate
Common Stock, issued (in shares)
Common Stock, oustanding (in shares)
Balance (in shares)
Balance (in shares)
Award Type [Domain]
Common Stock, authorized (in shares)
us-gaap_OperatingLeaseLeaseIncome
Operating Lease, Lease Income
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
Common Stock - 100,000,000 shares authorized, no par value; 16,985,919 shares issued and outstanding at June 30, 2026 and 17,057,397 shares issued and outstanding at December 31, 2025
Short-Term Debt, Type [Domain]
us-gaap_PolicyTextBlockAbstract
Accounting Policies
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
us-gaap_TableTextBlock
Notes Tables
Short-Term Debt, Type [Axis]
Subsequent Events [Text Block]
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less amount of payment representing interest
Amortization of right-of-use asset
Long-term debt and subordinated debentures
Total present value of lease payments
Lease liabilities - operating leases
Deposits
us-gaap_DepositsFairValueDisclosure
Standby Letters of Credit [Member]
Long-term debt, net of issuance costs
Recorded value
Offsetting Assets [Table]
Other Financial Institutions [Member]
Represents other financial institutions.
Statement of Stockholders' Equity [Abstract]
Statement of Comprehensive Income [Abstract]
Loss Contingency Nature [Axis]
CRA and other equity investments
Equity Securities, FV-NI
Statement of Cash Flows [Abstract]
2027, 250,000 and under
Amount of time deposit $250,000 or less maturing in next fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Core Deposits [Member]
Equity Components [Axis]
Change in operating lease liabilities
rbb_TimeDeposits250000OrLess
Total, 250,000 and under
Amount of time deposit liabilities, including certificates of deposit, in denominations of $250,000 or Less.
Equity Component [Domain]
Offsetting Liabilities [Table]
AOCI Attributable to Parent [Member]
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Corporate Debt Securities [Member]
Subordinated Borrowings Disclosure [Text Block]
Loss Contingency, Nature [Domain]
Subordinated Debt [Member]
us-gaap_SubordinatedDebt
Subordinated Debt
Subsequent Event Type [Domain]
Loans, gross
Loans, gross
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss
Financing Receivable, Nonaccrual [Table Text Block]
Subsequent Event [Table]
Subsequent Event Type [Axis]
Held to maturity (fair value of $4,078 and $4,103 at June 30, 2026 and December 31, 2025)
Available for sale, Amortized Cost
Intangible Asset and Goodwill [Text Block]
us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossExcludingAccruedInterest
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest
Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]
Share-Based Payment Arrangement, Option and Stock Appreciation Rights, Activity [Table Text Block]
us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Allowance for loan losses
Beginning balance
Ending balance
us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest
Other [Member]
Represents information related to other loans.
rbb_DebtInstrumentFaceAmountRepurchased
Debt Instrument Face Amount Repurchased
Face (par) amount of the original debt instrument that was repurchased.
Four fiscal year before current
us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear
Five fiscal year before current
us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear
rbb_StockRepurchaseProgramRemainingAuthorizedShareCount
Stock Repurchase Program, Remaining Authorized Share Count (in shares)
The remaining authorized share count of stock repurchase program.
Two fiscal year before current
us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear
rbb_AveragePricePaidPerShare
Average Price Paid Per Share (in dollars per share)
The average price paid per share of stock repurchased.
Three fiscal year before current
us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear
Current fiscal year
us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear
rbb_CommonStockSharesRepurchased
Common Stock, Shares Repurchased (in shares)
The number of shares repurchased of common stock.
Fiscal year before current
us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear
rbb_LoansReceivableInterest
Loans Receivable, Interest
The amount of interest on loans receivable.
Share-Based Payment Arrangement, Option [Member]
rbb_Tier2Capital
Tier 2 Capital
The amount of tier 2 capital.
Supplemental disclosure of cash flow information
Core deposit intangibles (2)
Revolving
us-gaap_FinancingReceivableExcludingAccruedInterestRevolving
Revolving converted to term loans
us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingConvertedToTermLoan
Treasury Stock [Text Block]
Long-term debt
us-gaap_LongTermDebtFairValue
Securities:
Loans held for sale
us-gaap_MortgagesHeldForSaleFairValueDisclosure
Lease, Cost [Table Text Block]
(Loss)/gain on OREO
us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy
Tier 1 Risk-Based Capital Ratio, Minimum Required for Capital Adequacy Purposes Amount
Long-Term Debt [Text Block]
Other Commitments [Table]
Tier 1 Risk-Based Capital Ratio, Amount
Common Stock, no par value (in dollars per share)
Interest-earning time deposits in other financial institutions
For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing time deposits in other financial institutions.
Tier 1 Leverage Ratio, Minimum Required for Capital Adequacy Purposes Amount
Tier 1 Leverage Ratio, Amount
2029
us-gaap_TimeDepositMaturitiesYearThree
2028
us-gaap_TimeDepositMaturitiesYearTwo
2027
us-gaap_TimeDepositMaturitiesYearOne
Other Commitments [Axis]
Other Commitments [Domain]
Data processing
Debt Disclosure [Text Block]
Non-controlling interest
Use of Estimates, Policy [Policy Text Block]
Federal Home Loan Bank Secured Line of Credit [Member]
Represents information related to the Federal Home Loan Bank secured line of credit.
Other Assets Disclosure [Text Block]
2030, 250,000 and under
Amount of time deposit maturing in fourth fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Total Risk-Based Capital Ratio, Minimum Required for Capital Adequacy Purposes Amount
2028, 250,000 and under
Amount of time deposit maturing in second fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
2029, 250,000 and under
Amount of time deposit maturing in third fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Total Risk-Based Capital Ratio, Amount
2029, greater than 250,000
Amount of time deposit maturing in third fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Lessee, Operating Leases [Text Block]
2028, greater than 250,000
Amount of time deposit maturing in second fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Principal amount
2030, greater than 250,000
Amount of time deposit maturing in fourth fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Mortgages [Member]
us-gaap_NoninterestExpense
Total noninterest expense
us-gaap_DebtInstrumentFaceAmount
Debt Instrument, Face Amount
Schedule of Other Assets [Table Text Block]
Noninterest expense:
Stock options exercised
Financial Asset, Not Past Due [Member]
rbb_InterestAndDividendIncomeOperatingAndNonoperating
Total consolidated revenues
Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.
Restricted stock units vested
Fair Value, Recurring and Nonrecurring [Table]
(Loss)/gain on other real estate owned
Amount of gains or loss on sale and transfer of other real estate owned.
Time-based Restricted Stock Units [Member]
Represents Time-based Restricted Stock Units.
Performance-based Restricted Stock Units [Member]
Represents Performance-based Restricted Stock Units.
Restricted Stock Units (RSUs) [Member]
Debt Instrument, Name [Domain]
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]
Stock options exercised (in shares)
Exercised, shares (in shares)
us-gaap_DebtInstrumentInterestRateStatedPercentage
Debt Instrument, Interest Rate, Stated Percentage
Restricted stock units vested (in shares)
Effective rate
Debt Instrument, Interest Rate, Effective Percentage
Related and Nonrelated Parties [Axis]
2027, greater than 250,000
Amount of time deposit over $250,000, maturing in next fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Unamortized valuation reserve
(Reversal of)/provision for credit losses
rbb_ProvisionForCreditLossesExpensed
The amount of provision for credit losses expensed.
Schedule of Long-Term Debt Instruments [Table]
Debt Instrument [Axis]
rbb_PaymentsToAcquireProceedsFromOtherInvestments
Purchase of other equity securities, net
The amount of cash outflow (inflow) from other investments.
Operating activities
Investing activities
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash provided by operating activities
Financing activities
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash used in investing activities
Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block]
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash provided by financing activities
Accounting Policies [Abstract]
Residential Collateralized Mortgage Obligations [Member]
Related to residential collateralized mortgage obligations.
Commercial Collateralized Mortgage Obligations [Member]
Related to commercial collateralized mortgage obligations.
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Segments [Axis]
us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss
Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss
Loans held for investment, net of allowance for loan losses
us-gaap_StockRepurchasedDuringPeriodValue
Repurchase of common stock
us-gaap_StockRepurchasedDuringPeriodShares
Repurchase of common stock (in shares)
Measurement Input Type [Axis]
Proceeds from sales of loans originally classified as HFI
The proceeds from the sale of loan originally held for investment.
Securities available for sale, amortized cost
Investment securities – AFS
Available for sale (amortized cost of $428,022 and $426,145 at June 30, 2026 and December 31, 2025)
us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted
Used in dilutive EPS, income
Net (decrease) increase in time deposits
Measurement Input, Discount Rate [Member]
Measurement Input, Default Rate [Member]
Measurement Input, Prepayment Rate [Member]
Four Percent Fixed To Floating Rate Subordinated Debentures Due April First Two Thousand Thirty One [Member]
Represents 4.00% fixed to floating rate subordinate debentures due April 1, 2031.
rbb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour
Thereafter, future minimum lease payments
Amount of lessee's undiscounted obligation for lease payment for operating lease due after fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
Used in basic EPS, income
us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Dividends Payable, Date of Record
Financial Asset, Past Due [Member]
Measurement Input Type [Domain]
us-gaap_InterestIncomeExpenseNet
Net interest income before (reversal of)/provision for credit losses
Measurement Input
Unused lines of Credit [Member]
Other Real Estate Owned, Measurement Input
Other Real Estate Owned, Measurement Input
us-gaap_ServicingAssetMeasurementInput
Servicing Asset, Measurement Input
Accounting Standards Update and Change in Accounting Principle [Table]
Non-cash investing and financing activities:
Occupancy and equipment expenses
Other expenses
Increase in cash surrender value of BOLI
us-gaap_NoninterestIncome
Total noninterest income
Noninterest income:
Office expenses
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested in Period, Fair Value
Measurement Basis [Axis]
us-gaap_GainsLossesOnSalesOfOtherRealEstate
Gains (Losses) on Sales of Other Real Estate
Gain on OREO
Other income
us-gaap_NoninterestIncomeOtherOperatingIncome
Gain on sale of loans
Gain on sale of loans
us-gaap_ValuationAllowancesAndReservesBalance
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount
Municipal Securities [Member]
Debt securities issued by state, city or local governments or the agencies operated by state, city or local governments.
us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Dividends Payable, Date to be Paid
(Reversal of)/provision for credit losses
Provision for/(reversal of) credit losses
Marketing and business promotion
Federal Home Loan Bank Overnight Advances [Member]
Overnight borrowings from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and also in times of liquidity shortages. The member institution executes a promissory note, which is generally collateralized by government securities to the Federal Reserve or loans.
us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery
Recoveries
Measurement Input, Adjustment [Member]
Measurement input using adjustments.
us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
YTD gross charge-offs
Charge-offs
Accrued interest and other liabilities
Amount of interest incurred but not yet paid, and liabilities classified as other.
Debt Instrument Redemption [Table]
Subordinated debentures, net
A debt instrument that embodies an unconditional obligation requiring the issuer to redeem the securities by transferring the assets at a specified or determinable date (or dates) or upon an event that is certain to occur.
Insurance and regulatory assessments
The amount of expense for insurance and regulatory assessments.
Legal and professional
The amount of expense (reversal of expense) in the period for legal and professional fees incurred on or before the balance sheet date.
Document Type
FHLB advances
rbb_InterestOnOtherBorrowedFunds
Amount of interest expense on borrowed funds classified as other.
FHLB stock
The amount of dividend income in the period on Federal Home Loan Bank stock.
Document Information [Line Items]
Document Quarterly Report
Directors and Their Affiliates [Member]
Represents directors and their affiliates.
Weighted-average remaining lease term (in years) (Year)
Document Information [Table]
Loan servicing income, net of amortization
Loan Servicing Fees Net of Amortization
The amount of loan servicing fees net of amortization.
Service charges and fees
The amount of service charges, fees, and income classified as other.
Depreciation and amortization of premises and equipment
The aggregate expense recognized in the current period that allocates the cost of premises and equipment to periods that benefit from use of the assets.
More than ten years, Held to maturity, Amortized Cost
rbb_NetAccretionOfSecuritiesLoansDepositsAndOther
Net accretion of securities, loans, deposits, and other
The amount of net accretion of securities, loans, deposits, and other investments.
More than one year to five years, Held to maturity, Amortized Cost
Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member]
Entity Interactive Data Current
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)
More than five years to ten years, Held to maturity, Amortized Cost
Document Transition Report
Less than one year, Held to Maturity, Amortized Cost
Diluted (in shares)
Held to maturity, Amortized Cost
Additions to servicing assets
Additions to the servicing asset during the period.
Basic (in shares)
Loans transferred to held for sale, net
(Transfer From) Transfer To Loans Held for Sale, Net
Value of loans and leases held in the entity's portfolio (transferred from) transferred to loans and leases held-for-sale in noncash transactions
Derivative Instrument [Axis]
rbb_IncreaseDecreaseInCashSurrenderValueOfLifeInsurance
Increase in cash surrender value of life insurance
The increase (decrease) during the period in the cash surrender value of life insurance policies.
Nonaccrual with no allowance for credit loss
Non-accrual Loans
Net increase in demand deposits and savings accounts
The increase (decrease) during the period in demand deposits and savings accounts.
rbb_PurchaseOfInvestmentInQualifiedAffordableHousingProjects
Net increase of investment in qualified affordable housing projects
The payments during the period for the purchase of investment in qualified affordable housing projects.
Title and Position [Domain]
Total Loans
rbb_LoansHeldForInvestmentAndHeldForSaleGross
The total carrying amount of loans held for investment, and loans held for sale before allowance of loan losses.
Total Deposits
us-gaap_Deposits
Deposits
Total deposits
us-gaap_DepositsWholesale
Deposits, Wholesale
Deposits:
Deposit Liabilities Disclosures [Text Block]
rbb_NumberOfBranches
Number of Branches
The number of branches operated during the period.
Noninterest-bearing demand
Document Fiscal Period Focus
Pledging Purpose [Axis]
Document Fiscal Year Focus
Pledging Purpose [Domain]
Amendment Flag
Federal Home Loan Bank Branch [Domain]
Schedule of Available for Sale Securities, and Held to Maturity [Table Text Block]
Tabular disclosure of available-for-sale securities and held-to-maturity securities.
Common Stock [Member]
Federal Home Loan Bank Branch [Axis]
Small Business Administration Agency Securities [Member]
Securities issued by the Small Business Association agency.
Document Period End Date
Legal Entity [Axis]
Interest and dividend income
us-gaap_InterestAndDividendIncomeOperating
Total interest and dividend income
Entity File Number
Entity Tax Identification Number
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Less than Twelve Months Unrealized Losses, available for sale
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Twelve Months or More Unrealized Losses, available for sale
Entity [Domain]
Entity Central Index Key
Entity Registrant Name
Entity Current Reporting Status
Entity Incorporation, State or Country Code
Current Fiscal Year End Date
Entity Filer Category
Entity Shell Company
Entity Emerging Growth Company
Entity Small Business
Single Family Residential Mortgages Loans [Member]
Represents information related to single family residential mortgages loans.
Other Loans [Member]
Represents information related to other loans.
Investments [Domain]
Derivative assets
us-gaap_DerivativeAssets
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Construction And Land Development Loans [Member]
Represents information related to construction and land development loans.
Small Business Administration Loans [Member]
Represents information related to small business administration loan.
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Nonvested, Number of Shares (in shares)
Derivative assets, notional amount
us-gaap_DerivativeAssetNotionalAmount
Entity Address, State or Province
us-gaap_PaymentsForOriginationAndPurchasesOfLoansHeldForSale
Loans originated for sale, net
Entity Address, City or Town
Entity Address, Address Line One
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Option, Nonvested, Weighted Average Exercise Price (in dollars per share)
City Area Code
More than one year to five years, Available for sale, Amortized Cost
Business Assets [Member]
Relating to business assets.
Mortgage And Small Business Administration Loans Serviced For Others [Table Text Block]
Tabular disclosure of mortgage and Small Business Administration loans serviced for others.
More than five years to ten years, Available for sale, Amortized Cost
Commercial Real Estate Collateral [Member]
Relating to commercial real estate collateral.
Loans serviced for others
Represent amount of loans serviced for others.
Local Phone Number
Government Assistance, Type [Domain]
Less than one year, Available for sale, Amortized Cost
Commerical Real Estate Loans [Member]
Represents information related to commercial real estate loans.
Entity Address, Postal Zip Code
Loan Servicing [Text Block]
The entire disclosure for loan servicing.
Schedule of Financing Receivables by Collateral Held [Table Text Block]
Tabular disclosure of financing receivables by collateral held.
SBA Loans [Member]
Represents information related to SBA loans.
Title of 12(b) Security
Security Exchange Name
More than five years to ten years, Available for sale, Estimated Fair Value
Trading Symbol
More than ten years, Available for sale, Estimated Fair Value
Less than one year, Available for sale, Estimated Fair Value
Available for sale, Estimated Fair Value, More than one year to five years
rbb_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFour
Thereafter
Amount of amortization for asset, excluding financial asset and goodwill, lacking physical substance with finite life expected to be recognized after fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).
More than ten years, Available for sale, Amortized Cost
Government Assistance, Type [Axis]
Variable Rate [Axis]
First American International Statutory Trust I 1[Member]
Represents information related to fist American international statutory trust !.
Variable Rate [Domain]
Entity Common Stock, Shares Outstanding
TFC Statutory Trust [Member]
Represents information related to TFC statutory trust.
Other comprehensive (loss)/income:
rbb_DebtAmortizationExpense
Debt Amortization Expense
Represents amortization expenses of debt.
Earnings Per Share [Text Block]
Preferred stock, no par value (in dollars per share)
us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax
Related income tax effect
PGB Holdings Inc And Banking Subsidiary Pacific Global Bank [Member]
Represents information related to PGB Holdings Inc and Banking Subsidiary Pacific Global Bank.
Director [Member]
Unrealized (loss)/gain on securities available for sale
Loans held for investment
Internal Credit Assessment [Axis]
Federal Reserve Bank of San Francisco Secured Line of Credit [Member]
Represents information related to Federal Reserve Bank of San Francisco secured line of credit.
Shares outstanding, shares (in shares)
Federal Home Loan Bank of San Francisco Secured Line of Credit [Member]
Represents information related to Federal Home Loan Bank of San Francisco secured line of credit.
Commercial And Similar Letters Of Credit [Member]
Represents information related to commercial and similar letters of credit.
Consolidated net income
Net income
Net income
Investment securities – HTM
Securities held to maturity, fair value
Securities held to maturity:
Principal Officers, Directors and their Affiliates [Member]
Represents information related to principal officers, directors and their affiliates.
rbb_UnfundedLoanCommitmentsAvailableToRelatedParties
Unfunded Loan Commitments, Available To Related Parties
Represents available to related parties for unfunded loan commitments.
Executive Officers, Directors and their Related Interests [Member]
Represents information related to executive officers, directors and their related interests.
Weighted-average common shares outstanding
rbb_ShareBasedCompensationArrangementByShareBasedPaymentAwardCommonStockReservedAsPercentageOfIssuedAndOutstanding
Share Based Compensation, Arrangement By Share Based Payment Award, Common Stock Reserved As Percentage Of Issued And Outstanding
Represents percentage of issued and outstanding for share based compensation by share based payment.
rbb_CapitalConservationBuffer
Capital Conservation Buffer
Represents information related to capital conservation buffer.
rbb_RequiredAssetsToLiabilitiesRatioAfterDividendEffect
Required Assets To Liabilities Ratio After Dividend Effect
Represents required assets to liabilities ratio after dividend effect.
Investments Classified by Contractual Maturity Date [Table Text Block]
Options exercisable, Aggregate Intrinsic Value
Internal Credit Assessment [Domain]
us-gaap_PaymentsForProceedsFromOtherInvestingActivities
Other investing activities, net
Servicing assets (1)
Servicing Asset
More than five years to ten years, Held to maturity, Fair Value
More than ten years, Held to maturity, Fair Value
rbb_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Common Equity Tier 1 Risk-Based Capital Ratio, Minimum Required for Capital Adequacy Purposes Ratio
Represents common equity tier one risk based capital required for capital adequacy to risk weighted assets.
Less than one year, Held to maturity, Estimated Fair Value
Tier 1 Leverage Ratio, Minimum Required Plus Capital Conservation Buffer Fully Phased-In Amount
Represents tire one leverage capital required plus capital conversion buffer fully phased in amount.
More than one year to five years, Held to maturity, Fair Value
Common Equity Tier 1 Risk-Based Capital Ratio, Minimum Required Plus Capital Conversation Buffer Fully Phased-In, Amount
Represents common equity tier once capital required plus capital conversion buffer fully phased in amount.
Basis of Accounting, Policy [Policy Text Block]
Common Equity Tier 1 Risk-Based Capital Ratio, Minimum Required Plus Capital Conversation Buffer Fully Phased-In, Ratio
Represents equity tier one capital required plus capital conversation buffer fully phased in to risk weighted assets.
Tier 1 Risk-Based Capital Ratio, Minimum Required Plus Capital Conversation Buffer Fully Phased-In, Ratio
Represents tier one risk based capital required plus capital conversation buffer fully phased in to risk weighted assets.
Total Risk-Based Capital Ratio, Minimum Required Plus Capital Conversation Buffer Fully Phased-In, Ratio
Represents capital required for capital conversation buffer fully phased in to risk weighted assets.
Tier 1 Risk-Based Capital Ratio, Minimum Required Plus Capital Conversation Buffer Fully Phased-In, Amount
Represents tier one risk based capital required plus capital conversation buffer fully phased in amount.
Total Risk-Based Capital Ratio, Minimum Required Plus Capital Conversation Buffer Fully Phased-In, Amount
Represents capital required for capital conversation buffer fully phased in amount.
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]
Tier 1 Leverage Ratio, Minimum Required Plus Capital Conservation Buffer Fully Phased-In Ratio
Represents tier one leverage capital required plus capital conservation buffer fully phased in average assets.
Regulatory Capital Requirements under Banking Regulations [Text Block]
Total Assets
us-gaap_Assets
Assets
Total assets
Other Real Estate Owned [Member]
Represents information related to other real estate owned.
Fees And Service Charges On Deposit Accounts [Member]
Represents information related to fees and service charges on deposit accounts.
Other Fees [Member]
Represents information related to other fees.
Other Service Income [Member]
Represents information related to other service income.
Impact of weighting shares, shares (in shares)
Represents weighted average number of shares impact.
RBB Bancorp [Member]
Represents information related to RBB Bancorp.
Royal Business Bank [Member]
Represents information related to Royal Business Bank.
Modified loans, balance
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount
Modified loans, percent
us-gaap_NotesReceivableGross
Financing Receivable, before Allowance for Credit Loss
Modified loans, accumulated balance
Diluted (in dollars per share)
us-gaap_FinancingReceivableExcludingAccruedInterestModifiedSubsequentDefault
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default
Other real estate owned ("OREO")
Other Real Estate
Accounts and Financing Receivables [Table]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Financial Asset, 30 to 89 Days Past Due [Member]
Financial asset more than 29 days past due but fewer than 90 days past due.
Advance With One Time Call, Three Month Lock Out [Member]
Relating to Advance With One Time Call, Three Month Lock Out
Participating Mortgage Loans [Table]
rbb_RetainedEarningsAdjustmentForStockRepurchases
Repurchase of common stock
Represents the adjustment to retained earnings for stock repurchases.
Intangible Asset, Finite-Lived [Table]
us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest
Total comprehensive income
Advance With One Time Call, Six Month Lock Out [Member]
Relating to Advance With One Time Call, Six Month Lock Out.
Advance With One Time Call, One Year Lock Out [Member]
Relating to Advance With One Time Call, One Year Lock Out.
us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
Equity, Including Portion Attributable to Noncontrolling Interest
Total shareholders’ equity
Balance
Balance
Five fiscal year before current, write offs
Revolving, write offs
Three fiscal year before current, write offs
Shareholders' equity:
Four fiscal year before current, write offs
Fiscal year before current, write offs
Two fiscal year before current, write offs
Extended Maturity and Interest Rate Reduction [Member]
Current fiscal year write offs
Revolving converted to term loans, write offs
Noncontrolling Interest [Member]
Forfeited/cancelled, weighted-average grant date fair value (in dollars per share)
us-gaap_PaymentsOfDividends
Cash dividends paid
us-gaap_RepaymentsOfFederalHomeLoanBankBorrowings
Repayments of FHLB Advances
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
Commitments and contingencies - Note 13
Statistical Measurement [Axis]
srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Share Repurchase Program, Authorized, Number of Shares (in shares)
us-gaap_DividendsPayableDateDeclaredDayMonthAndYear
Dividends Payable, Date Declared
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Trading Arrangements, by Individual [Table]
Material Terms of Trading Arrangement [Text Block]
Financial Instrument [Axis]
us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Held to maturity, gross unrealized losses
Held to maturity, gross unrealized gains
Minimum [Member]
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Available for sale, gross unrealized losses
Available for sale, gross unrealized gains
Statistical Measurement [Domain]
Maximum [Member]
Federal Home Loan Bank, Advances [Table Text Block]
Federal Home Loan Bank, Advances, Putable Option [Member]
Federal Home Loan Bank, Advances, Option [Axis]
Federal Home Loan Bank, Advances, Option [Domain]
Commercial Mortgage-Backed Securities [Member]
us-gaap_EffectiveIncomeTaxRateContinuingOperations
Effective Income Tax Rate Reconciliation, Percent
Forfeited/cancelled, weighted average exercise price (in dollars per share)
Exercised, weighted average exercise price (in dollars per share)
us-gaap_DividendsCash
Cash dividends on common stock
Financial Instruments [Domain]
us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRate
Federal Home Loan Bank, Advances, Weighted Average Interest Rate
Common stock dividends per share (in dollars per share)
Common Stock, Dividends, Per Share, Declared (in dollars per share)
Asset Pledged as Collateral [Member]
Less than Twelve Months, Number of Positions, available for sale
Twelve Months or More, number of positions, available for sale
Dividends [Axis]
Dividends [Domain]
Twelve Months or More Estimated Fair Value, available for sale
Less than Twelve Months Estimated Fair Value, available for sale
Award Type [Axis]
Adjustments to reconcile net income to net cash from operating activities:
Plan Name [Axis]
Plan Name [Domain]
us-gaap_AllocatedShareBasedCompensationExpense
Share-Based Payment Arrangement, Expense
Title and Position [Axis]
us-gaap_ShareBasedCompensation
Stock-based compensation, net
Subsequent Event [Member]
Federal Home Loan Bank of San Francisco [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum
Share-Based Compensation Arrangement by Share-Based Payment Award, Percentage of Outstanding Stock Maximum
Share-Based Payment Arrangement [Text Block]
us-gaap_FiniteLivedIntangibleAssetUsefulLife
Finite-Lived Intangible Asset, Useful Life (Year)
Preferred stock, outstanding (in shares)
Held for Investment Loans [Member]
Relating to held for investment loans.
Preferred stock, authorized (in shares)
Portion at Fair Value Measurement [Member]
Reported Value Measurement [Member]
Cash and cash equivalents
Estimate of Fair Value Measurement [Member]
Time deposits $250,000 and under
The amount of time deposits with amounts of $250,000 and under.
New Accounting Pronouncements, Policy [Policy Text Block]
Antidilutive Securities, Name [Domain]
us-gaap_DebtInstrumentRepurchaseAmount
Debt Instrument, Repurchase Amount
Statement [Table]
Accrued interest receivable (1)
rbb_InterestReceivableFairValueDisclosure
Fair value portion of interest earned but not received.
Accrued interest payable (2)
rbb_InterestPayableFairValueDisclosure
Fair value portion of interest payable on debt.
us-gaap_DebtInstrumentRepurchasedFaceAmount
Debt Instrument, Repurchased Face Amount
us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Total Unrealized Losses, available for sale
Loans, net
us-gaap_LoansReceivableFairValueDisclosure
Total Estimated Fair Value, available for sale
Investment in FHLB stock
us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure
Total Number of Positions, available for sale
Nature of Operations [Text Block]
srt_StockRepurchaseProgramAuthorizedAmount1
Share Repurchase Program, Authorized, Amount
Long-Term Debt, Type [Axis]
FHLB advances
us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure
Product and Service [Domain]
Product and Service [Axis]
Forward Mortgage Loan Sale Contracts [Member]
Represents forward mortgage loan sale contracts.
Consolidated Entities [Axis]
Consolidated Entities [Domain]
rbb_BrokeredTimeDeposits
Brokered Time Deposits
Amount of brokered time deposits.
Deposits [Member]
Residential Mortgage-Backed Securities [Member]
Commitments to Make Loans [Member]
Represents commitments to make loans.
The 2017 Omnibus Stock Incentive Plan [Member]
Represents the 2017 Omnibus Stock Incentive Plan.
Assets
Statement [Line Items]
Amortization of investment in affordable housing tax credits
Investment Program, Proportional Amortization Method, Applied, Amortization Expense
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
2028
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
2029
Allowance for Credit Loss and Unfunded Loan Commitments [Member]
Represents allowance for credit loss and unfunded loan commitments.
LIHTC investments
Investment, Proportional Amortization Method, Elected, Amount
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
2027
us-gaap_MortgageLoansInProcessOfForeclosureAmount
Mortgage Loans in Process of Foreclosure, Amount
us-gaap_QualifiedAffordableHousingProjectInvestmentsCommitment
Investment Program, Proportional Amortization Method, Elected, Commitment
us-gaap_AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount
Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization Expense
Certificates of Deposit Held Through CDARS [Member]
Represents Certificates of Deposit Held Through CDARS.
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear
Remainder of 2026
us-gaap_AffordableHousingProjectInvestmentWriteDownAmount
Investment Program, Proportional Amortization Method, Elected, Impairment Loss
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
2030
ICS [Member]
Represents ICS (Insured Cash Sweeps).
rbb_DebtSecuritiesHeldtomaturityUnrealizedLossPositionAccumulatedLoss1
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss 1
Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value 1
Fair value of investment in debt security measured at amortized cost (held-to-maturity), in unrealized loss position.
rbb_DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss1
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 1
Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for less than 12 months.
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value 1
Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for less than 12 months.
rbb_DebtSecuritiesHeldtomaturityContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss1
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 1
Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for 12 months or longer.
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value 1
Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for 12 months or longer.
Advance amount
Long-Term Federal Home Loan Bank Advances
us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities
Maturities, repayments and calls
Advance interest rate
Maturities, repayments and calls
Outstanding, Weighted Average Remaining Contractual Term (Year)
Loans held for sale
us-gaap_ServicingAssetAtAmortizedValueAmortization1
Amortization
Options exercisable, Weighted Average Remaining Contractual Term (Year)
2030 and thereafter
us-gaap_TimeDepositMaturitiesRollingYearFour
Federal Home Loan Bank Advances [Member]
Remainder of 2026
us-gaap_TimeDepositMaturitiesRemainderOfFiscalYear
Subordinated debentures
us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations
Federal Home Loan Bank (FHLB) stock
Proceeds from sales of OREO
Payment Deferral [Member]
Intangible Asset, Finite-Lived, Class [Axis]
Extended Maturity [Member]
Loan Restructuring Modification [Axis]
Intangible Asset, Finite-Lived, Class [Domain]
Loan Restructuring Modification [Domain]
Proceeds from loans sold
Financing Receivable Portfolio Segment [Axis]
Long-Term Debt, Type [Domain]
Unfunded Loan Commitment [Member]
Financing Receivable Portfolio Segment [Domain]
Exercise of stock options
Proceeds from Stock Options Exercised
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
Fair Value, Inputs, Level 1 [Member]
Real Estate [Member]
Financial Asset, Aging [Axis]
Premises and equipment, net
Prepaid assets
Net deferred tax assets
Financial Asset, Aging [Domain]
(Reversal of) provision for credit losses
us-gaap_ProvisionForLoanLeaseAndOtherLosses
(Reversal of)/provision for credit losses
Financial Asset, 30 to 59 Days Past Due [Member]
Stock-based compensation, net
Proceeds from FHLB advances
The amount of increase in short-term advances from Federal Home Loan Bank.
Financial Asset, 60 to 89 Days Past Due [Member]
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Fair Value Disclosures [Text Block]
Fair Value, by Balance Sheet Grouping [Table Text Block]
TFC Trust
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions 1
Number of investments in debt securities held-to-maturity, in continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.
Debt Securities, Held-to-Maturity, Unrealized Loss Position, Number of Positions 1
Number of investments in debt securities held-to-maturity, in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.
Secured Overnight Financing Rate (SOFR) [Member]
Collateral Held [Domain]
Collateral Held [Axis]
us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Gain on sale of fixed assets
Accumulated other comprehensive loss, net
Noninterest income, not in scope (3)
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Net income before income taxes
us-gaap_AdditionalPaidInCapital
Additional paid-in capital
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)
Collateral Pledged [Member]
Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less Than 12 Months, Number of Positions 1
Number of investments in debt securities held-to-maturity, in continuous unrealized loss position for less than 12 months, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.
Core deposit intangible amortization
The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets.
rbb_PaymentsForProceedsFromLoansAndLeasesExcludingLoansHeldForInvestment
Net increase in loans
The net cash outflow or inflow for the increase (decrease) in the beginning and end of period of loan and lease balances which are not originated or purchased specifically for resale. Includes cash payments and proceeds, excluding loans held for investment.
us-gaap_OffBalanceSheetCreditLossLiability
Off-Balance-Sheet, Credit Loss, Liability
FHLB advances
us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt
Purchases
us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt
Proceeds from Sale of Debt Securities, Available-for-Sale
Assets measured at fair value
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
us-gaap_InterestRevenueExpenseNet
Segment net interest income and noninterest income
Segments [Domain]
Federal Home Loan Bank, Advances, Term [Member]
Federal Home Loan Bank, Advances, Term
Accrued interest and other assets
Total accrued interest and other assets
Savings, NOW and money market accounts
Income Statement [Abstract]
us-gaap_OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal
Off-Balance-Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
us-gaap_AmortizationOfFinancingCosts
Amortization of Debt Issuance Costs
us-gaap_GovernmentAssistanceAwardAmount
Government Assistance, Award Amount
Amortization of intangible assets
Intangible Asset, Finite-Lived, Amortization Expense
Income Tax, Examination [Table]
us-gaap_OtherCommitment
Other Commitment
us-gaap_RegulatoryAssets
Regulatory Assets, Total
Income Tax Disclosure [Text Block]
us-gaap_FinancingReceivableNonaccrualInterestIncome
Financing Receivable, Nonaccrual, Interest Income
Income tax receivable
Related and Nonrelated Parties [Domain]
us-gaap_RelatedPartyDepositLiabilities
Related Party Deposit Liabilities
Related Party Transaction [Table]
Related Party Transactions Disclosure [Text Block]
Debt Securities, Available-for-Sale, Allowance for Credit Loss [Table]
Fair Value Hierarchy and NAV [Domain]
Transfer from loans to other real estate owned
Measurement Frequency [Domain]
Statement of Financial Position [Abstract]
Class of Treasury Stock [Table]
Time deposits over $250,000
Total, greater than 250,000
(Refunds received) taxes paid
Other assets
Fair Value, Nonrecurring [Member]
Fair Value, Recurring [Member]
Common Equity Tier 1 Risk-Based Capital Ratio, Amount
us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy
Common Equity Tier 1 Risk-Based Capital Ratio, Minimum Required for Capital Adequacy Purposes Amount
us-gaap_PaymentsForRepurchaseOfCommonStock
Common stock repurchased, net of repurchase costs
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)
Antidilutive Securities [Axis]
Net income per share
Dilutive effect of outstanding stock options & RSUs (in shares)
Basic (in dollars per share)
Earnings Per Share, Basic, by Common Class, Including Two-Class Method [Table]
us-gaap_FiniteLivedIntangibleAssetsNet
Total, amortization expense
us-gaap_FiniteLivedIntangibleAssetsGross
Intangible Asset, Finite-Lived, before Accumulated Amortization
Commitments Disclosure [Text Block]
Financing Receivable, Past Due [Table]
Goodwill
Goodwill
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Table]
Commercial Portfolio Segment [Member]
Business Combination [Domain]
Business Combination [Axis]
Disaggregation of Revenue [Table Text Block]
Disaggregation of Revenue [Table]
Doubtful [Member]
Special Mention [Member]
Substandard [Member]
Pass [Member]
Other comprehensive income (loss), net of taxes
Total other comprehensive (loss)/income
Valuation Approach and Technique [Axis]
Equity securities (1)
us-gaap_EquityFairValueDisclosure
Financing Receivable, Modified [Table]
Interest expense:
Interest-earning deposits in other financial institutions
Interest-earning deposits with financial institutions
Valuation Approach and Technique [Domain]
Other segment items (1)
us-gaap_SegmentReportingOtherItemAmount
Valuation, Market Approach [Member]
us-gaap_InterestExpenseDebt
Interest Expense, Debt
Time deposits
Retained earnings
Interest expense
us-gaap_InterestExpenseOperating
Total interest expense
us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation
Restricted stock units vesting
Revenue from Contract with Customer [Text Block]
Class of Stock [Axis]
Class of Financing Receivable [Axis]
Class of Financing Receivable [Domain]
Other items
Recognition of operating lease right-of-use assets
Represents amount of operating lease right-of-use assets recognized during the period.
Financing Receivable, Credit Quality Indicator [Table]
Savings deposits, NOW and money market accounts
Recognition of operating lease liabilities
Represents amount of operating lease liabilities recognized during the period.
Deferred tax expense (benefit)
us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss
Net interest income after (reversal of)/provision for credit losses
Interest-earning deposits
Federal funds sold and other
Derivative Contract [Domain]
Cash and due from banks
us-gaap_CashAndCashEquivalentsAtCarryingValue
Cash and cash equivalents
Financing Receivable, Nonaccrual [Table]
Time Deposits Acquired Through Internet Listing Services [Member]
Represents Time Deposits Acquired Through Internet Listing Services.
Other revenues
us-gaap_OtherInterestAndDividendIncome
Collateralized Deposits From the State of California [Member]
Represents Collateralized Deposits From the State of California.
us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Common Stock, Capital Shares Reserved for Future Issuance (in shares)
Investment securities
Time Deposit Maturities [Table Text Block]
Asset Class [Domain]
Investment Type [Axis]
Accrued interest receivable
Interest paid
Cash surrender value of bank owned life insurance (BOLI)
Schedule of Subordinated Debentures [Table Text Block]
Tabular disclosure of subordinated debentures.
PGBH Trust [Member]
Related to PGBH Trust
TFC Trust [Member]
Related to TFC Trust.
FAIC Trust [Member]
Related to FAIC trust.
Tenor spread adjustment
The percent amount of tenor spread adjustment for debt instrument.
Nature of Operation, Product Information, Concentration of Risk [Table]
Affordable Housing Partnerships and SBIC Funds [Member]
Relating to affordable housing partnerships and SBIC funds.
ROU assets
Right-of-use assets - operating leases
us-gaap_FinancialInstrumentsOwnedAtFairValue
Financial Instruments, Owned, at Fair Value
us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss
Total in-scope noninterest income