3.21.2 html 387 437 1 false 76 0 false 7 false false R1.htm 0001001 - Document - Cover Sheet http://myopenbank.com/role/Cover Cover Cover 1 false false R2.htm 1001002 - Statement - CONSOLIDATED BALANCE SHEETS (unaudited) Sheet http://myopenbank.com/role/CONSOLIDATEDBALANCESHEETSunaudited CONSOLIDATED BALANCE SHEETS (unaudited) Statements 2 false false R3.htm 1002003 - Statement - CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) Sheet http://myopenbank.com/role/CONSOLIDATEDBALANCESHEETSUnauditedParenthetical CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) Statements 3 false false R4.htm 1003004 - Statement - CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (unaudited) Sheet http://myopenbank.com/role/CONSOLIDATEDSTATEMENTSOFINCOMEANDCOMPREHENSIVEINCOMEunaudited CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (unaudited) Statements 4 false false R5.htm 1004005 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (unaudited) Sheet http://myopenbank.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINSHAREHOLDERSEQUITYunaudited CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (unaudited) Statements 5 false false R6.htm 1005006 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (unaudited) (Parenthetical) Sheet http://myopenbank.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINSHAREHOLDERSEQUITYunauditedParenthetical CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (unaudited) (Parenthetical) Statements 6 false false R7.htm 1006007 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) Sheet http://myopenbank.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWSunaudited CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) Statements 7 false false R8.htm 2101101 - Disclosure - Business Description Sheet http://myopenbank.com/role/BusinessDescription Business Description Notes 8 false false R9.htm 2103102 - Disclosure - Summary of Significant Accounting Policies Sheet http://myopenbank.com/role/SummaryofSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 9 false false R10.htm 2108103 - Disclosure - Securities Sheet http://myopenbank.com/role/Securities Securities Notes 10 false false R11.htm 2115104 - Disclosure - Loans and Allowance for Loan Losses Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLosses Loans and Allowance for Loan Losses Notes 11 false false R12.htm 2127105 - Disclosure - Premises and Equipment Sheet http://myopenbank.com/role/PremisesandEquipment Premises and Equipment Notes 12 false false R13.htm 2131106 - Disclosure - Servicing Assets Sheet http://myopenbank.com/role/ServicingAssets Servicing Assets Notes 13 false false R14.htm 2135107 - Disclosure - Deposits Sheet http://myopenbank.com/role/Deposits Deposits Notes 14 false false R15.htm 2139108 - Disclosure - Borrowing Arrangements Sheet http://myopenbank.com/role/BorrowingArrangements Borrowing Arrangements Notes 15 false false R16.htm 2143109 - Disclosure - Income Taxes Sheet http://myopenbank.com/role/IncomeTaxes Income Taxes Notes 16 false false R17.htm 2145110 - Disclosure - Commitments and Contingencies Sheet http://myopenbank.com/role/CommitmentsandContingencies Commitments and Contingencies Notes 17 false false R18.htm 2150111 - Disclosure - Stock-based Compensation Sheet http://myopenbank.com/role/StockbasedCompensation Stock-based Compensation Notes 18 false false R19.htm 2156112 - Disclosure - Employee Benefit Plan Sheet http://myopenbank.com/role/EmployeeBenefitPlan Employee Benefit Plan Notes 19 false false R20.htm 2158113 - Disclosure - Fair Value of Financial Instruments Sheet http://myopenbank.com/role/FairValueofFinancialInstruments Fair Value of Financial Instruments Notes 20 false false R21.htm 2165114 - Disclosure - Regulatory Capital Matters Sheet http://myopenbank.com/role/RegulatoryCapitalMatters Regulatory Capital Matters Notes 21 false false R22.htm 2169115 - Disclosure - Earnings Per Share Sheet http://myopenbank.com/role/EarningsPerShare Earnings Per Share Notes 22 false false R23.htm 2204201 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://myopenbank.com/role/SummaryofSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://myopenbank.com/role/SummaryofSignificantAccountingPolicies 23 false false R24.htm 2305301 - Disclosure - Summary of Significant Accounting Policies (Tables) Sheet http://myopenbank.com/role/SummaryofSignificantAccountingPoliciesTables Summary of Significant Accounting Policies (Tables) Tables http://myopenbank.com/role/SummaryofSignificantAccountingPolicies 24 false false R25.htm 2309302 - Disclosure - Securities (Tables) Sheet http://myopenbank.com/role/SecuritiesTables Securities (Tables) Tables http://myopenbank.com/role/Securities 25 false false R26.htm 2316303 - Disclosure - Loans and Allowance for Loan Losses (Tables) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesTables Loans and Allowance for Loan Losses (Tables) Tables http://myopenbank.com/role/LoansandAllowanceforLoanLosses 26 false false R27.htm 2328304 - Disclosure - Premises and Equipment (Tables) Sheet http://myopenbank.com/role/PremisesandEquipmentTables Premises and Equipment (Tables) Tables http://myopenbank.com/role/PremisesandEquipment 27 false false R28.htm 2332305 - Disclosure - Servicing Assets (Tables) Sheet http://myopenbank.com/role/ServicingAssetsTables Servicing Assets (Tables) Tables http://myopenbank.com/role/ServicingAssets 28 false false R29.htm 2336306 - Disclosure - Deposits (Tables) Sheet http://myopenbank.com/role/DepositsTables Deposits (Tables) Tables http://myopenbank.com/role/Deposits 29 false false R30.htm 2340307 - Disclosure - Borrowing Arrangements (Tables) Sheet http://myopenbank.com/role/BorrowingArrangementsTables Borrowing Arrangements (Tables) Tables http://myopenbank.com/role/BorrowingArrangements 30 false false R31.htm 2346308 - Disclosure - Commitments and Contingencies (Tables) Sheet http://myopenbank.com/role/CommitmentsandContingenciesTables Commitments and Contingencies (Tables) Tables http://myopenbank.com/role/CommitmentsandContingencies 31 false false R32.htm 2351309 - Disclosure - Stock-based Compensation (Tables) Sheet http://myopenbank.com/role/StockbasedCompensationTables Stock-based Compensation (Tables) Tables http://myopenbank.com/role/StockbasedCompensation 32 false false R33.htm 2359310 - Disclosure - Fair Value of Financial Instruments (Tables) Sheet http://myopenbank.com/role/FairValueofFinancialInstrumentsTables Fair Value of Financial Instruments (Tables) Tables http://myopenbank.com/role/FairValueofFinancialInstruments 33 false false R34.htm 2366311 - Disclosure - Regulatory Capital Matters (Tables) Sheet http://myopenbank.com/role/RegulatoryCapitalMattersTables Regulatory Capital Matters (Tables) Tables http://myopenbank.com/role/RegulatoryCapitalMatters 34 false false R35.htm 2370312 - Disclosure - Earnings Per Share (Tables) Sheet http://myopenbank.com/role/EarningsPerShareTables Earnings Per Share (Tables) Tables http://myopenbank.com/role/EarningsPerShare 35 false false R36.htm 2402401 - Disclosure - Business Description - Additional Information (Details) Sheet http://myopenbank.com/role/BusinessDescriptionAdditionalInformationDetails Business Description - Additional Information (Details) Details 36 false false R37.htm 2406402 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details) Sheet http://myopenbank.com/role/SummaryofSignificantAccountingPoliciesAdditionalInformationDetails Summary of Significant Accounting Policies - Additional Information (Details) Details 37 false false R38.htm 2407403 - Disclosure - Summary of Significant Accounting Policies - Summary of Consideration Paid for Loan Portfolio and Amounts of Assets Purchased (Details) Sheet http://myopenbank.com/role/SummaryofSignificantAccountingPoliciesSummaryofConsiderationPaidforLoanPortfolioandAmountsofAssetsPurchasedDetails Summary of Significant Accounting Policies - Summary of Consideration Paid for Loan Portfolio and Amounts of Assets Purchased (Details) Details 38 false false R39.htm 2410404 - Disclosure - Securities - Schedule of Amortized Cost, Corresponding Amounts of Gross Unrealized Gains and Losses and Estimated Fair Value of AFS Debt Securities (Details) Sheet http://myopenbank.com/role/SecuritiesScheduleofAmortizedCostCorrespondingAmountsofGrossUnrealizedGainsandLossesandEstimatedFairValueofAFSDebtSecuritiesDetails Securities - Schedule of Amortized Cost, Corresponding Amounts of Gross Unrealized Gains and Losses and Estimated Fair Value of AFS Debt Securities (Details) Details 39 false false R40.htm 2411405 - Disclosure - Securities - Additional Information (Details) Sheet http://myopenbank.com/role/SecuritiesAdditionalInformationDetails Securities - Additional Information (Details) Details 40 false false R41.htm 2412406 - Disclosure - Securities - Schedule of Amortized Cost and Estimated Fair Value of Securities AFS Debt Securities by Contractual Maturity (Details) Sheet http://myopenbank.com/role/SecuritiesScheduleofAmortizedCostandEstimatedFairValueofSecuritiesAFSDebtSecuritiesbyContractualMaturityDetails Securities - Schedule of Amortized Cost and Estimated Fair Value of Securities AFS Debt Securities by Contractual Maturity (Details) Details 41 false false R42.htm 2413407 - Disclosure - Securities -Schedule of Fair Value and Associated Gross Unrealized Losses on AFS Debt Securities by Length of Time in Continuous Loss (Details) Sheet http://myopenbank.com/role/SecuritiesScheduleofFairValueandAssociatedGrossUnrealizedLossesonAFSDebtSecuritiesbyLengthofTimeinContinuousLossDetails Securities -Schedule of Fair Value and Associated Gross Unrealized Losses on AFS Debt Securities by Length of Time in Continuous Loss (Details) Details 42 false false R43.htm 2414408 - Disclosure - Securities - Schedule of Other Investments Securities (Details) Sheet http://myopenbank.com/role/SecuritiesScheduleofOtherInvestmentsSecuritiesDetails Securities - Schedule of Other Investments Securities (Details) Details 43 false false R44.htm 2417409 - Disclosure - Loans and Allowance for Loan Losses - Composition of Loan Portfolio (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesCompositionofLoanPortfolioDetails Loans and Allowance for Loan Losses - Composition of Loan Portfolio (Details) Details 44 false false R45.htm 2418410 - Disclosure - Loans and Allowance for Loan Losses - Additional Information (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesAdditionalInformationDetails Loans and Allowance for Loan Losses - Additional Information (Details) Details 45 false false R46.htm 2419411 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Activity in Allowance for Loan Losses by Portfolio Segment (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofActivityinAllowanceforLoanLossesbyPortfolioSegmentDetails Loans and Allowance for Loan Losses - Schedule of Activity in Allowance for Loan Losses by Portfolio Segment (Details) Details 46 false false R47.htm 2420412 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Allowance for Loan Losses and Recorded Investment by Portfolio Segment and Impairment Methodology (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofAllowanceforLoanLossesandRecordedInvestmentbyPortfolioSegmentandImpairmentMethodologyDetails Loans and Allowance for Loan Losses - Schedule of Allowance for Loan Losses and Recorded Investment by Portfolio Segment and Impairment Methodology (Details) Details 47 false false R48.htm 2421413 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Recorded Investment of Individually Impaired Loans and Specific Allowance for Loan Losses (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofRecordedInvestmentofIndividuallyImpairedLoansandSpecificAllowanceforLoanLossesDetails Loans and Allowance for Loan Losses - Schedule of Recorded Investment of Individually Impaired Loans and Specific Allowance for Loan Losses (Details) Details 48 false false R49.htm 2422414 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Average Recorded Investment In Impaired Loans and Amount of Interest Income Recognized on Impaired Loans by Portfolio Segment (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofAverageRecordedInvestmentInImpairedLoansandAmountofInterestIncomeRecognizedonImpairedLoansbyPortfolioSegmentDetails Loans and Allowance for Loan Losses - Schedule of Average Recorded Investment In Impaired Loans and Amount of Interest Income Recognized on Impaired Loans by Portfolio Segment (Details) Details 49 false false R50.htm 2423415 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Recorded Investment in Nonaccrual Loans and Loans Past Due 90 or More Days and Still Accruing Interest by Portfolio Segment (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofRecordedInvestmentinNonaccrualLoansandLoansPastDue90orMoreDaysandStillAccruingInterestbyPortfolioSegmentDetails Loans and Allowance for Loan Losses - Schedule of Recorded Investment in Nonaccrual Loans and Loans Past Due 90 or More Days and Still Accruing Interest by Portfolio Segment (Details) Details 50 false false R51.htm 2424416 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Aging Analysis of Recorded Investment in Past Due Loans (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofAgingAnalysisofRecordedInvestmentinPastDueLoansDetails Loans and Allowance for Loan Losses - Schedule of Aging Analysis of Recorded Investment in Past Due Loans (Details) Details 51 false false R52.htm 2425417 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Loan Deferment Status Change by Loan Type (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofLoanDefermentStatusChangebyLoanTypeDetails Loans and Allowance for Loan Losses - Schedule of Loan Deferment Status Change by Loan Type (Details) Details 52 false false R53.htm 2426418 - Disclosure - Loans and Allowance for Loan Losses - Schedule of Credit Risk Ratings by Portfolio Segment (Details) Sheet http://myopenbank.com/role/LoansandAllowanceforLoanLossesScheduleofCreditRiskRatingsbyPortfolioSegmentDetails Loans and Allowance for Loan Losses - Schedule of Credit Risk Ratings by Portfolio Segment (Details) Details 53 false false R54.htm 2429419 - Disclosure - Premises and Equipment - Schedule of Premises and Equipment (Details) Sheet http://myopenbank.com/role/PremisesandEquipmentScheduleofPremisesandEquipmentDetails Premises and Equipment - Schedule of Premises and Equipment (Details) Details 54 false false R55.htm 2430420 - Disclosure - Premises and Equipment - Additional Information (Details) Sheet http://myopenbank.com/role/PremisesandEquipmentAdditionalInformationDetails Premises and Equipment - Additional Information (Details) Details 55 false false R56.htm 2433421 - Disclosure - Servicing Assets - Additional Information (Details) Sheet http://myopenbank.com/role/ServicingAssetsAdditionalInformationDetails Servicing Assets - Additional Information (Details) Details 56 false false R57.htm 2434422 - Disclosure - Servicing Assets - Schedule of Changes in Activity for Loan Servicing Assets (Details) Sheet http://myopenbank.com/role/ServicingAssetsScheduleofChangesinActivityforLoanServicingAssetsDetails Servicing Assets - Schedule of Changes in Activity for Loan Servicing Assets (Details) Details 57 false false R58.htm 2437423 - Disclosure - Deposits - Additional Information (Details) Sheet http://myopenbank.com/role/DepositsAdditionalInformationDetails Deposits - Additional Information (Details) Details 58 false false R59.htm 2438424 - Disclosure - Deposits - Schedule of Maturities of Time Deposits (Details) Sheet http://myopenbank.com/role/DepositsScheduleofMaturitiesofTimeDepositsDetails Deposits - Schedule of Maturities of Time Deposits (Details) Details 59 false false R60.htm 2441425 - Disclosure - Borrowing Arrangements - Additional Information (Details) Sheet http://myopenbank.com/role/BorrowingArrangementsAdditionalInformationDetails Borrowing Arrangements - Additional Information (Details) Details 60 false false R61.htm 2442426 - Disclosure - Borrowing Arrangements - Summary of Borrowings Available to the Company from Institutions (Details) Sheet http://myopenbank.com/role/BorrowingArrangementsSummaryofBorrowingsAvailabletotheCompanyfromInstitutionsDetails Borrowing Arrangements - Summary of Borrowings Available to the Company from Institutions (Details) Details 61 false false R62.htm 2444427 - Disclosure - Income Taxes - Additional Information (Details) Sheet http://myopenbank.com/role/IncomeTaxesAdditionalInformationDetails Income Taxes - Additional Information (Details) Details 62 false false R63.htm 2447428 - Disclosure - Commitments and Contingencies - Summary of Distribution of Undisbursed Credit-related Commitments (Details) Sheet http://myopenbank.com/role/CommitmentsandContingenciesSummaryofDistributionofUndisbursedCreditrelatedCommitmentsDetails Commitments and Contingencies - Summary of Distribution of Undisbursed Credit-related Commitments (Details) Details 63 false false R64.htm 2448429 - Disclosure - Commitments and Contingencies - Investments in Low Income Housing Partnerships, Net and Related Unfunded Commitments (Details) Sheet http://myopenbank.com/role/CommitmentsandContingenciesInvestmentsinLowIncomeHousingPartnershipsNetandRelatedUnfundedCommitmentsDetails Commitments and Contingencies - Investments in Low Income Housing Partnerships, Net and Related Unfunded Commitments (Details) Details 64 false false R65.htm 2449430 - Disclosure - Commitments and Contingencies - Additional Information (Details) Sheet http://myopenbank.com/role/CommitmentsandContingenciesAdditionalInformationDetails Commitments and Contingencies - Additional Information (Details) Details 65 false false R66.htm 2452431 - Disclosure - Stock-based Compensation - Additional Information (Details) Sheet http://myopenbank.com/role/StockbasedCompensationAdditionalInformationDetails Stock-based Compensation - Additional Information (Details) Details 66 false false R67.htm 2453432 - Disclosure - Stock-based Compensation - Summary of Stock-based Compensation Stock Options Activity (Details) Sheet http://myopenbank.com/role/StockbasedCompensationSummaryofStockbasedCompensationStockOptionsActivityDetails Stock-based Compensation - Summary of Stock-based Compensation Stock Options Activity (Details) Details 67 false false R68.htm 2454433 - Disclosure - Stock-based Compensation - Summary of Information Related to Stock Option Plan (Details) Sheet http://myopenbank.com/role/StockbasedCompensationSummaryofInformationRelatedtoStockOptionPlanDetails Stock-based Compensation - Summary of Information Related to Stock Option Plan (Details) Details 68 false false R69.htm 2455434 - Disclosure - Stock-based Compensation - Summary of Changes in Non-vested Restricted Stock Awards (Details) Sheet http://myopenbank.com/role/StockbasedCompensationSummaryofChangesinNonvestedRestrictedStockAwardsDetails Stock-based Compensation - Summary of Changes in Non-vested Restricted Stock Awards (Details) Details 69 false false R70.htm 2457435 - Disclosure - Employee Benefit Plan - Additional Information (Details) Sheet http://myopenbank.com/role/EmployeeBenefitPlanAdditionalInformationDetails Employee Benefit Plan - Additional Information (Details) Details 70 false false R71.htm 2460436 - Disclosure - Fair Value of Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) Sheet http://myopenbank.com/role/FairValueofFinancialInstrumentsSummaryofAssetsandLiabilitiesMeasuredatFairValueonRecurringBasisDetails Fair Value of Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) Details 71 false false R72.htm 2461437 - Disclosure - Fair Value of Financial Instruments - Summary of Fair Value Hierarchy and Fair Value of Assets That Were Still Held and Had Fair Value Adjustments Measured On a Nonrecurring Basis (Details) Sheet http://myopenbank.com/role/FairValueofFinancialInstrumentsSummaryofFairValueHierarchyandFairValueofAssetsThatWereStillHeldandHadFairValueAdjustmentsMeasuredOnaNonrecurringBasisDetails Fair Value of Financial Instruments - Summary of Fair Value Hierarchy and Fair Value of Assets That Were Still Held and Had Fair Value Adjustments Measured On a Nonrecurring Basis (Details) Details 72 false false R73.htm 2462438 - Disclosure - Fair Value of Financial Instruments - Summary of Increase (Decrease) In Value of Certain Assets Held at End of Respective Reporting Periods Presented for Which a Nonrecurring Fair Value Adjustment (Details) Sheet http://myopenbank.com/role/FairValueofFinancialInstrumentsSummaryofIncreaseDecreaseInValueofCertainAssetsHeldatEndofRespectiveReportingPeriodsPresentedforWhichaNonrecurringFairValueAdjustmentDetails Fair Value of Financial Instruments - Summary of Increase (Decrease) In Value of Certain Assets Held at End of Respective Reporting Periods Presented for Which a Nonrecurring Fair Value Adjustment (Details) Details 73 false false R74.htm 2463439 - Disclosure - Fair Value of Financial Instruments - Summary of Information about Significant Unobservable Inputs Utilized in Company's Nonrecurring Level 3 Fair Value Measurements (Details) Sheet http://myopenbank.com/role/FairValueofFinancialInstrumentsSummaryofInformationaboutSignificantUnobservableInputsUtilizedinCompanysNonrecurringLevel3FairValueMeasurementsDetails Fair Value of Financial Instruments - Summary of Information about Significant Unobservable Inputs Utilized in Company's Nonrecurring Level 3 Fair Value Measurements (Details) Details 74 false false R75.htm 2464440 - Disclosure - Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) Sheet http://myopenbank.com/role/FairValueofFinancialInstrumentsCarryingAmountsandEstimatedFairValuesofFinancialInstrumentsDetails Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) Details 75 false false R76.htm 2467441 - Disclosure - Regulatory Capital Matters - Additional Information (Details) Sheet http://myopenbank.com/role/RegulatoryCapitalMattersAdditionalInformationDetails Regulatory Capital Matters - Additional Information (Details) Details 76 false false R77.htm 2468442 - Disclosure - Regulatory Capital Matters - Summary of Actual and Required Capital Amounts and Ratios (Details) Sheet http://myopenbank.com/role/RegulatoryCapitalMattersSummaryofActualandRequiredCapitalAmountsandRatiosDetails Regulatory Capital Matters - Summary of Actual and Required Capital Amounts and Ratios (Details) Details 77 false false R78.htm 2471443 - Disclosure - Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Details) Sheet http://myopenbank.com/role/EarningsPerShareComputationofBasicandDilutedEarningsPerShareDetails Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Details) Details 78 false false R79.htm 2472444 - Disclosure - Earnings Per Share - Additional Information (Details) Sheet http://myopenbank.com/role/EarningsPerShareAdditionalInformationDetails Earnings Per Share - Additional Information (Details) Details 79 false false All Reports Book All Reports opbk-20210930.htm opbk-20210930.xsd opbk-20210930_cal.xml opbk-20210930_def.xml opbk-20210930_lab.xml opbk-20210930_pre.xml opbk-20210930xex311.htm opbk-20210930xex312.htm opbk-20210930xex321.htm opbk-20210930xex322.htm http://fasb.org/us-gaap/2020-01-31 http://xbrl.sec.gov/dei/2020-01-31 http://fasb.org/srt/2020-01-31 true true