Revision of Prior Period [Axis] Revision of Prior Period [Axis] Accrued but unpaid expenses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Investment Securities and Allowance for Credit Losses on Investment Securities Investment, Policy [Policy Text Block] Schedule of Available-for-Sale Investments Debt Securities, Available-for-Sale [Table Text Block] Held-to-maturity Securities, Amortized Cost Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date [Abstract] Award Timing Predetermined Award Timing Predetermined [Flag] Entity File Number Entity File Number Total income Income (Loss) from Subsidiaries, before Tax Interest bearing: Interest-Bearing Deposit Liabilities [Abstract] Stock options exercised, net of shares surrendered for cashless exercises and tax withholdings Stock Issued During Period, Value, Stock Options Exercised, Net Of Shares Surrendered For Cashless Exercises And Tax Withholdings Stock Issued During Period, Value, Stock Options Exercised, Net Of Shares Surrendered For Cashless Exercises And Tax Withholdings Tabular List, Table Tabular List [Table Text Block] Stock options exercised, net of shares surrendered for cashless exercises and tax withholdings (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Net Of Shares Surrendered For Cashless Exercises And Tax Withholdings Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Net Of Shares Surrendered For Cashless Exercises And Tax Withholdings Accounting Standards Adopted in 2025 and Accounting Standards Not Yet Adopted New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Schedule of Fair Value by Balance Sheet Grouping Fair Value, by Balance Sheet Grouping [Table Text Block] Federal Funds Purchased Federal Funds Purchased [Member] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Measurement Basis [Axis] Adjustment to Compensation: Adjustment to Compensation [Axis] Held-to-maturity, greater than or equal to 12 continuous months, fair value Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Threshold period a past due overdraft account is charged off Threshold Period Past Due For Write-Off Of Deposit Liabilities Reclassified As Loans Receivable Threshold Period Past Due For Write-Off Of Deposit Liabilities Reclassified As Loans Receivable Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-Based Compensation Cost Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Recoveries Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery Number of securities Marketable Securities, Number Of Securities Marketable Securities, Number Of Securities Stock issued under employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Total current tax (benefit) provision Current Income Tax Expense (Benefit) After one but within five years Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year One through Five Adjustment to Compensation, Amount Adjustment to Compensation Amount Common Equity Tier 1 (to risk-weighted assets), Actual, Ratio Tier One Common Equity To Average Assets Tier One Common Equity To Average Assets Concentration risk percentage Concentration Risk, Percentage Net changes in interest receivable and other assets Other assets Increase (Decrease) in Other Operating Assets Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Interest rate contracts notional amount, asset derivatives Derivative Asset, Notional Amount Stock Options Share-Based Payment Arrangement, Option [Member] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Decrease (increase) in fair value of interest rate swaps hedging loans receivable Decrease (Increase) In Fair Value Of Interest Rate Fair Value Hedging Instruments Decrease (Increase) In Fair Value Of Interest Rate Fair Value Hedging Instruments Cash, Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Debit card interchange fees, net Debit Card [Member] Percent Effective Income Tax Rate Reconciliation, Percent [Abstract] Cash dividends paid on common stock Cash dividends to common stockholders Dividends, Common Stock, Cash Total stockholders' equity Beginning balance Ending balance Stockholders' equity Equity, Attributable to Parent Measurement Frequency [Axis] Measurement Frequency [Axis] After five years through ten years Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 5 through 10 Aa1 / AA+ Moody's And/Or Standard & Poor's AA Rating [Member] Moody's And/Or Standard & Poor's AA Rating Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Insider Trading Policies and Procedures [Line Items] Schedule of Bank Premises and Equipment Property, Plant and Equipment [Table Text Block] Common stock, authorized (in shares) Common Stock, Shares Authorized Schedule of Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits, by Title of Individual and by Type of Deferred Compensation [Table] Deferred Compensation Arrangement with Individual, Excluding Share-Based Payment and Postretirement Benefit [Table] Financial assets (recorded at amortized cost) Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Hedged interest earned (paid) Derivative, Hedged Interest Earned (Paid) Payment on interest rate swaps recorded in interest income. Assets and Liabilities at Fair Value Measured on a Recurring Basis Fair Value, Recurring [Member] Credit loss on held-to-maturity securities Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Period Increase (Decrease) Tier 1 Leverage Capital (to average assets), Threshold to be a Well Capitalized Bank Holding Company, Amount Banking Regulation, Tier 1 Leverage Capital, Well Capitalized, Minimum Liabilities and Stockholders' Equity Liabilities and stockholders' equity Liabilities and Equity [Abstract] California State State and Local Jurisdiction [Member] Cover [Abstract] Cover [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Amortized cost Held to maturity, amortized cost Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss Maximum Maximum [Member] Stock Options Exercisable, Weighted Average Exercise Price (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price Useful life of core deposit intangible asset Finite-Lived Intangible Asset, Useful Life Available-for-sale, total securities in a loss position, fair value Debt Securities, Available-for-Sale, Unrealized Loss Position Total Finite-Lived Intangible Assets, Net After ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 Collateral pledged Debt Instrument, Collateral Amount Restricted Stock Restricted Stock Award Restricted Stock [Member] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Concentrations of Credit Risk Concentration Risk Disclosure [Text Block] Number of investment securities in unrealized loss position longer than 12 months Marketable Securities In Unrealized Loss Positions, Qualitative Disclosure, Number Of Positions, Longer Than 12 Months Marketable Securities In Unrealized Loss Positions, Qualitative Disclosure, Number Of Positions, Longer Than 12 Months Allowance for Credit Losses on Unfunded Loan Commitments Off-Balance-Sheet Credit Exposure, Policy [Policy Text Block] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Debt securities, sold at par value Debt Securities, Available-for-Sale, Sold at Par Value Commercial non-owner occupied Commercial Loan, Non-Owner-Occupied [Member] Commercial Loan, Non-Owner-Occupied Retirement Benefits [Abstract] Retirement Benefits [Abstract] OREO valuation allowance adjustment Real Estate Owned, Valuation Allowance, Valuation Increase Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Other assets Other Assets [Member] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Weighted-Average Term Extension (in years) Financing Receivable, Modified, Weighted Average Term Increase from Modification Schedule of Operating and Finance Lease Right-of-use Assets and Lease Liabilities Assets And Liabilities, Lessee [Table Text Block] Assets And Liabilities, Lessee [Table Text Block] (Loss) income before provision for income taxes Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Tier 1 Leverage Capital (to average assets), Actual, Ratio Banking Regulation, Tier 1 Leverage Capital Ratio, Actual U.S. Government And Government-Sponsored Enterprises U.S. Government And Government-Sponsored Enterprises [Member] U.S. Government And Government-Sponsored Enterprises Average Balance Long-Term Debt, Average Amount Outstanding Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Proceeds from sale of premises and equipment Proceeds from Sale of Property, Plant, and Equipment Net unrealized losses on securities transferred from held-to-maturity to available-for-sale Other Comprehensive Income (Loss), Reclassification Adjustment From AOCI For Investment Transferred From Held-To-Maturity To Available-For-Sale, Before Tax Other Comprehensive Income (Loss), Reclassification Adjustment From AOCI For Investment Transferred From Held-To-Maturity To Available-For-Sale, Before Tax Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Operating Segments Operating Segments [Member] Schedule of Income Taxes Paid (Net of Refunds) Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Operating lease, remaining lease term (in years) Lessee, Operating Lease, Remaining Lease Term Average Rate Debt And Finance Lease Liability, Average Interest Rate Debt And Finance Lease Liability, Average Interest Rate Minimum employment period to qualify for 401(k) plan Defined Contribution Plan, Minimum Employment Period to Qualify for Plan Defined Contribution Plan, Minimum Employment Period to Qualify for Plan Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Line of Credit Facility [Table] Line of Credit Facility [Table] Total interest expense Total interest expense Interest Expense, Operating Exercise Price Range [Axis] Exercise Price Range [Axis] Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Nontaxable or nondeductible items Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent [Abstract] Interest on finance lease liabilities Finance Lease, Interest Expense Marketable securities, less than 12 continuous months, fair value Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Document Fiscal Period Focus Document Fiscal Period Focus Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Award Timing Method Award Timing Method [Text Block] Non-accrual loans Financing Receivable, Excluding Accrued Interest, Nonaccrual Total Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss Furniture and Fixtures Furniture and equipment Furniture and Fixtures [Member] Total finance lease cost Finance Lease, Cost Finance Lease, Cost Award Type [Axis] Award Type [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Bancorp Parent Company [Member] Transfers of Financial Assets Transfers and Servicing of Financial Assets, Transfers of Financial Assets, Policy [Policy Text Block] Investment, Name [Domain] Investment, Name [Domain] Share-Based Compensation Share-Based Payment Arrangement [Policy Text Block] Trading Symbol Trading Symbol 2029 Lessee, Operating Lease, Liability, to be Paid, Year Four Business Combinations Business Combination [Policy Text Block] Percentage of commitments expiring between 2027 and 2033 Loan Commitments And Standby Letters of Credit, Percentage Expiring In Year Two Through Seven Loan Commitments And Standby Letters of Credit, Percentage Expiring In Year Two Through Seven Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Entity Address, City or Town Entity Address, City or Town Short-term Debt, Type [Domain] Short-Term Debt, Type [Domain] Weighted average discount rate Finance Lease, Weighted Average Discount Rate, Percent Proceeds from sale of Visa Inc. Class B restricted common stock Proceeds From Sale Of Restricted Common Stock Proceeds From Sale Of Restricted Common Stock Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Repayment of proceeds from short-term borrowings, net Proceeds from (Repayments of) Short-Term Debt Allowance for Credit Losses on Loans ("ACL") Credit Loss, Financial Instrument [Policy Text Block] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Schedule of Bond Ratings for Held-to-Maturity Securities Debt Securities, Held-to-Maturity, Credit Quality Indicator [Table Text Block] Scheduled time deposit maturities Maturities of Time Deposits [Abstract] Emerging Growth Company Entity Emerging Growth Company Schedule of Held-to-Maturity Investments Debt Securities, Held-to-Maturity [Table Text Block] Weighted average remaining term (in years) Finance Lease, Weighted Average Remaining Lease Term General Business Tax Credit Carryforward, Qualified Zone Academy Bond General Business Tax Credit Carryforward, Qualified Zone Academy Bond Carryforward [Member] General Business Tax Credit Carryforward, Qualified Zone Academy Bond Carryforward Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Pledged Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset Held-to-maturity, less than 12 continuous months, unrealized loss Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Options outstanding, beginning balance (in shares) Options outstanding, ending balance (in shares) Stock Options Outstanding (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Condensed Bank of Marin Bancorp Parent Only Financial Statements Condensed Financial Information of Parent Company Only Disclosure [Text Block] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Wealth management and trust services, Service charges on deposit accounts, Debit card interchange fees, net and Merchant interchange fees, net Revenue from Contract with Customer, Including Assessed Tax Debt issuance costs Debt Issuance Costs, Net Net gain (loss) recognized in interest income on loans Derivative, Gain (Loss) on Derivative, Net Secured Loan Asset Type Benchmark Secured Loan Asset Type Benchmark [Member] Secured Loan Asset Type Benchmark Schedule of Maturities for Time Deposits Schedule of Maturities for Time Deposits [Table Text Block] Schedule of Maturities for Time Deposits [Table Text Block] Restricted cash Restricted Cash and Cash Equivalent Interest on time accounts Interest on time accounts Interest Expense, Time Deposits Total non-interest income Non-interest income Noninterest Income Amounts representing interest (present value discount) Finance Lease, Liability, Undiscounted Excess Amount Common stock, outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Insurance [Abstract] Insurance [Abstract] Gross unrealized losses Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Federal Reserve Bank of San Francisco Federal Reserve Bank of San Francisco [Member] Federal Reserve Bank of San Francisco Loans and Allowance for Credit Losses on Loans Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Non-interest expense Non-interest expense Noninterest Expense [Abstract] Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Current tax(benefit) provision Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Counterparty Counterparty [Member] Counterparty Charitable contribution carryforwards Deferred Tax Assets, Charitable Contribution Carryforwards Shares awarded in period from plan (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] After one but within five years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items] Debt Securities, Held-to-Maturity, Credit Quality Indicator [Line Items] Weighted-Average Interest Rate Reduction Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Average Balance Debt And Finance Lease Liability, Average Balance Debt And Finance Lease Liability, Average Balance (Benefit from) provision for income taxes Income tax benefit Total income tax (benefit) provision Income Tax Expense (Benefit) Information technology Information Technology The amount of expenses incurred in the period for information technology products and services. Purchased loans Payments to Acquire Loans Receivable Basis spread Debt Instrument, Basis Spread on Variable Rate Other assets Other Assets Thereafter Time Deposit Maturities, after Year Five Preferred stock, issued, (in shares) Preferred Stock, Shares Issued Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Hedging Relationship [Axis] Hedging Relationship [Axis] Bank premises and equipment, gross Property, Plant and Equipment, Gross Financial Instruments with Off-Balance Sheet Risk Financial Instruments with Off-Balance Sheet Risk [Text Block] Financial Instruments with Off-Balance Sheet Risk [Text Block] Regulatory Assets and Liabilities Disclosure [Abstract] Regulatory Assets and Liabilities Disclosure [Abstract] Occupancy and equipment Occupancy And Equipment Includes: 1) occupancy expense that may include items, such as maintenance and repair of facilities and equipment, lease expenses, rentals, property taxes and property and casualty insurance expense; and 2) furniture and equipment purchases which do not qualify for capitalization in accordance with the entity's accounting policy. Within one year Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Borrowings and other obligations Other Debt and Lease Obligations Other Debt and Lease Obligations Nonaccrual interest income reversal Financing Receivable, Nonaccrual, Interest Income Reversal Financing Receivable, Nonaccrual, Interest Income Reversal Federal Home Loan Bank Branch [Domain] Federal Home Loan Bank Branch [Domain] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Installment and other consumer loans Installment And Other Consumer [Member] Installment And Other Consumer [Member] Proceeds from stock options exercised Proceeds from Stock Options Exercised Accumulated depreciation and amortization Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, Accumulated Depreciation and Amortization Schedule of Misstatements and Related Restatements Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Federal Income Tax Paid, Federal, after Refund Received All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Tax-exempt interest, net of TEFRA Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent Non-Accrual Financing Receivable, Nonaccrual, Modified In Period, Amount Financing Receivable, Nonaccrual, Modified In Period, Amount Other adjustments Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Other income Noninterest Income, Other Operating Income Non-vested awards, beginning balance (in shares) Non-vested awards, ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Debt securities, available-for-sale unrealized loss position, allowance for credit loss Debt Securities, Available-For-Sale Unrealized Loss Position, Allowance For Credit Loss Debt Securities, Available-For-Sale Unrealized Loss Position, Allowance For Credit Loss Restricted stock forfeited/cancelled (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Forfeited Effective Income Tax Rate Reconciliation [Table] Effective Income Tax Rate Reconciliation [Table] Sales proceeds Proceeds from Sale of Debt Securities, Available-for-Sale Available-for-sale, at fair value (net of zero allowance for credit losses at December 31, 2025 and 2024) Fair Value Total Debt Securities, Available-for-Sale, Excluding Accrued Interest Proceeds from sale of other real estate owned Proceeds from Sale of Other Real Estate Premises and equipment useful life Property, Plant and Equipment, Useful Life Subsequent Event Subsequent Event [Member] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Period before ratable vesting begins Defined Benefits Plan, Period Before Ratable Vesting Begins Defined Benefits Plan, Period Before Ratable Vesting Begins Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Net interest income Interest Income (Expense), Operating Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Tier 1 Capital (to risk-weighted assets), Actual, Amount Banking Regulation, Tier 1 Risk-Based Capital, Actual Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Depreciation and amortization Depreciation 2029 Finance Lease, Liability, to be Paid, Year Four Gross Amounts of Recognized Liabilities Derivative Liability, Subject to Master Netting Arrangement, before Offset Equity Components [Axis] Equity Components [Axis] Financing receivable, originated, year four Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Personal and other lines of credit Consumer and Other Lines of Credit [Member] Consumer and Other Lines of Credit [Member] State franchise tax Deferred Tax Assets, State Taxes Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of reportable segments Number of Reportable Segments Benefit Plans Compensation and Employee Benefit Plans [Text Block] Commercial Real Estate Commercial Real Estate [Member] Advertising Costs Advertising Cost [Policy Text Block] Earnings on bank-owned life insurance, net Bank Owned Life Insurance Income, Net, Excluding Death Benefits Bank Owned Life Insurance Income, Net, Excluding Death Benefits Entity Address, State or Province Entity Address, State or Province Substandard Substandard [Member] Repayment of finance lease obligations Finance Lease, Principal Payments Total interest income Interest income Interest and Dividend Income, Operating Interest on federal funds sold and due from banks Interest Due From Banks And Other Interest Due From Banks And Other Financial Asset, Period Past Due [Domain] Financial Asset, Aging [Domain] Special Mention Special Mention [Member] Loans, net of allowance for credit losses Loans Receivable, Fair Value Disclosure Operating and finance lease liabilities Deferred Tax Assets, Operating Lease And Finance Lease, Liability Deferred Tax Assets, Operating Lease And Finance Lease, Liability Restricted stock granted (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Individual: Individual [Axis] Employer contributions Defined Contribution Plan, Cost Subtotal Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization Income Tax Jurisdiction [Domain] Income Tax Jurisdiction [Domain] Right-of-use assets obtained in exchange for finance lease liabilities Right-of-Use Asset Obtained in Exchange for Finance Lease Liability Accounting Changes and Error Corrections [Abstract] Cash dividends paid on common stock Cash dividends paid on common stock Payments of Ordinary Dividends, Common Stock Document Annual Report Document Annual Report Concentration risk, paydowns Concentration Risk, Credit Risk, Financial Instrument, Paydowns Concentration Risk, Credit Risk, Financial Instrument, Paydowns Period used to determine amount available for payment of dividends based on restriction (in years) Dividends, Cash Dividend, Period Restricted Payment Amount is Determined Dividends, Cash Dividend, Period Restricted Payment Amount is Determined Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Tier 1 Capital (to risk-weighted assets), Adequately Capitalized Threshold, Amount Banking Regulation, Tier 1 Risk-Based Capital, Capital Adequacy, Minimum Entity Interactive Data Current Entity Interactive Data Current Gross realized gain Equity Securities, FV-NI, Realized Gain Revolving home equity lines Home Equity Line of Credit [Member] Financing Receivable, Troubled Debt Restructuring [Line Items] Financing Receivable, Modified [Line Items] Number of retail branches Number Of Retail Branches Number Of Retail Branches Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Financing Receivable Portfolio Concentration Risk Financing Receivable Portfolio Concentration Risk [Member] Financing Receivable Portfolio Concentration Risk Interest income Interest and Dividend Income, Operating [Abstract] Total non-interest expense Non-interest expense Noninterest Expense Reconciliation of income Segment Reconciliation [Abstract] Net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Property, Plant and Equipment, Type [Axis] Long-Lived Tangible Asset [Axis] Non-interest income Noninterest Income [Abstract] 2027 Finance Lease, Liability, to be Paid, Year Two Income before income taxes and equity in undistributed net income of subsidiary Income (Loss) Before Income Taxes and Equity in Undistributed Net Income of Subsidiary Income (Loss) Before Income Taxes and Equity in Undistributed Net Income of Subsidiary Accumulated amortization Finance Lease, Right-of-Use Asset, Accumulated Amortization Data processing Data Processing, Adjusted Data Processing, Adjusted Schedule of Condensed Financial Statements [Table] Condensed Financial Statements [Table] Schedule of Unrecognized Compensation Cost, Nonvested Awards Share-Based Payment Arrangement, Nonvested Award, Cost [Table Text Block] Entity Central Index Key Entity Central Index Key PEO Name PEO Name Partners' Capital, Other Ownership Interest [Table] Partners' Capital, Other Ownership Interest [Table] Error Correction [Table] Error Correction [Table] Stock repurchased, including commissions Stock repurchased, including commissions and excise tax Payments for Repurchase of Equity Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Schedule of Financing Receivable Credit Quality Indicators Financing Receivable Credit Quality Indicators [Table Text Block] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Comprehensive (loss) income : Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Tier 1 Leverage Capital (to average assets), Adequately Capitalized Threshold, Amount Banking Regulation, Tier 1 Leverage Capital, Capital Adequacy, Minimum Defined Benefit Plan [Table] Defined Benefit Plan [Table] Non-interest bearing Noninterest-Bearing Deposit Liabilities Share-Based Payment Arrangement, Tranche One Share-Based Payment Arrangement, Tranche One [Member] Nontaxable or nondeductible items Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount [Abstract] Commercial owner-occupied Commercial real estate, owner-occupied Commercial Real Estate Loan, Owner-Occupied [Member] Commercial Real Estate Loan, Owner-Occupied [Member] Other residential Other Residential Loan [Member] Loans to purchase or refinance residential real estate, mostly secured by tenancy-in-common, or “TIC” loans. Schedule of Derivative Instruments in Statement of Financial Position, Fair Value Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Class of Stock [Domain] Class of Stock [Domain] Debt securities, available for sale transferred from held to maturity, book value sold Held-To-Maturity Securities Transferred To Available-For-Sale Amortized Cost Held-To-Maturity Securities Transferred To Available-For-Sale Amortized Cost Federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Subsequent Event Type [Axis] Subsequent Event Type [Axis] Cumulative Amounts of Fair Value Hedging Adjustments Included in the Carrying Amounts of the Hedged Assets Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease) Capital contribution to bank subsidiary Capital Contribution To Subsidiary Bank Capital Contribution To Subsidiary Bank Statement of Financial Position Location, Balance [Axis] Statement of Financial Position Location, Balance [Axis] 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Three Vesting [Domain] Vesting [Domain] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Time deposits of less than or equal to $250 thousand Time Deposits, Less Than Or Equal To $250,000 Time Deposits, Less Than Or Equal To $250,000 Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range Share-Based Payment Arrangement, Option, Exercise Price Range [Table Text Block] Accumulated Other Comprehensive Income (Loss), Net of Taxes AOCI Attributable to Parent [Member] Investments [Domain] Investments [Domain] Restricted stock surrendered for tax withholdings upon vesting (in shares) Number of shares withheld (in shares) Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Derivative Financial Instruments and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Range of Exercise Prices, Lower Limit (in dollars per share) Share-Based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit Fair Value as of Grant Date Award Grant Date Fair Value Carrying value of securities carried at cost Equity Securities, FV-NI, Cost Available-for-sale: Debt Securities, Available-for-Sale, Realized Gain (Loss) [Abstract] Net operating loss carryforwards expected to expire Operating Loss Carryforwards Financing receivable, originated, year five Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year Common Equity Tier 1 (to risk-weighted assets), Threshold to be a Well Capitalized Bank Holding Company, Ratio Tier One Common Equity Required to be Well Capitalized to Average Assets Tier One Common Equity Required to be Well Capitalized to Average Assets Salaries and employee benefits Labor and Related Expense Non-Government Sponsored Enterprises Mortgage-Backed Securities, Issued by Private Enterprises [Member] Type of Deferred Compensation, All Types [Domain] Deferred Bonus and Profit Sharing Arrangement, Individual Contract, Type of Deferred Compensation [Domain] Total adjustments Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity Stock options (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Tier 1 Leverage Capital (to average assets), Adequately Capitalized Threshold, Ratio Banking Regulation, Tier 1 Leverage Capital Ratio, Capital Adequacy, Minimum Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Title of Individual with Relationship to Entity [Domain] Title and Position [Domain] Cancelled or forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Unrecognized compensation expense Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Related Party Transaction [Line Items] Related Party Transaction [Line Items] Available-for-sale, less than 12 continuous months, fair value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Tier 1 Capital (to risk-weighted assets), Actual, Ratio Banking Regulation, Tier 1 Risk-Based Capital Ratio, Actual Deposits Deposit Liabilities Disclosures [Text Block] Earnings on bank-owned life insurance policies Bank Owned Life Insurance Income Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Counterparty Name [Domain] Counterparty Name [Domain] Held-to-maturity, greater than or equal to 12 continuous months, unrealized loss Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] 2027 Lessee, Operating Lease, Liability, to be Paid, Year Two Debentures of government-sponsored agencies Debentures of government sponsored agencies US Government-sponsored Enterprises Debt Securities [Member] Condensed Financial Information Disclosure [Abstract] Condensed Financial Information Disclosure [Abstract] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Options outstanding Stock Options Outstanding, Remaining Contractual Life (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Other comprehensive income, before tax Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, before Tax, Portion Attributable to Parent Investment Type [Axis] Investment Type [Axis] Deferred tax expense Other Comprehensive Income (Loss), Available-for-Sale Securities, Tax, Portion Attributable to Parent Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration] Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration] Total investment securities Investments Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Debt Securities, Held-to-maturity, Fair Value Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value [Abstract] Non-PEO NEO Non-PEO NEO [Member] Options outstanding, beginning balance Options outstanding, ending balance Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Stock issued under employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Unvested restricted stock awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends Tier 1 Capital (to risk-weighted assets), Adequately Capitalized Threshold, Ratio Tier One Risk Based Capital Required For Capital Adequacy With Buffer To Risk Weighted Assets Tier One Risk Based Capital Required For Capital Adequacy With Buffer To Risk Weighted Assets Interest rate contracts notional amount, liability derivatives Derivative Liability, Notional Amount Land Land [Member] Gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Average Balance Finance Lease Liability, Average Balance Finance Lease Liability, Average Balance Cash and due from Bank of Marin Cash and Due from Subsidiary Cash and Due from Subsidiary Award Type [Domain] Award Type [Domain] 2026 Lessee, Operating Lease, Liability, to be Paid, Year One Equity Awards Adjustments Equity Awards Adjustments [Member] Leasehold improvements Leasehold Improvements [Member] Advertising costs Advertising Expense Multiple Modifications Multiple Modifications [Member] Multiple Modifications Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Total Capital (to risk-weighted assets), Threshold to be a Well Capitalized Bank Holding Company, Amount Banking Regulation, Total Risk-Based Capital, Well Capitalized, Minimum Deferred tax (benefit) provision Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Interest and fees on loans Interest And Fees On Loans [Member] Interest And Fees On Loans Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Other real estate owned Other Real Estate Owned Expense Other Real Estate Owned Expense Expected dividend yield on common stock Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Fair Value Estimate of Fair Value Measurement [Member] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Net Amounts of Assets Presented in the Statements of Condition Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral After one but within five years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five Proceeds from sale of available-for-sale securities transferred from held-to-maturity Proceeds From Sale Of Available-For-Sale Securities Transferred From Held-To-Maturity Proceeds From Sale Of Available-For-Sale Securities Transferred From Held-To-Maturity Percentage of commitments expiring thereafter Loan Commitments And Standby Letters Of Credit, Percentage Expiring, After Year Seven Loan Commitments And Standby Letters Of Credit, Percentage Expiring, After Year Seven Deferred compensation and salary continuation plans Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions Reclassification adjustment for losses on available-for-sale securities included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Service charges on deposit accounts Deposit Account [Member] 2029 Time Deposit Maturities, Year Four Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] After five years through ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Schedule of Financial Instruments Owned and Pledged as Collateral Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block] Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Amount [Abstract] Marketable Securities, Continuous Unrealized Loss Marketable Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract] Marketable Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract] Proceeds from issuance of subordinated notes Proceeds from issuance of subordinated notes, net of issuance costs Proceeds from Issuance of Subordinated Long-Term Debt Accumulated other comprehensive loss, net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Debt securities, available for sale transferred from held to maturity, pre tax loss Held-To-Maturity Securities Transferred To Available-For-Sale, Gain (Loss), Before Tax Held-To-Maturity Securities Transferred To Available-For-Sale, Gain (Loss), Before Tax Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Financial Instruments [Domain] Financial Instruments [Domain] Core deposit intangible, net Finite-Lived Core Deposits, Gross After ten years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Total gross deferred tax liabilities Deferred Tax Liabilities, Gross Proceeds from stock options exercised and stock issued under employee and director stock purchase plans Proceeds from Stock Options Exercised and Employee Stock Purchases Proceeds from Stock Options Exercised and Employee Stock Purchases Schedule of Information of Cashless Exercise Prices Share-based Payment Arrangement, Share Information about Cashless Exercises [Table Text Block] Share-based Payment Arrangement, Share Information about Cashless Exercises Performance Shares Performance Shares [Member] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Total Modifications Total Loan Restructuring Modification [Member] Total Loan Restructuring Modification Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Banking Regulation, Regulatory Capital Requirement, Compliance [Table] Banking Regulation, Regulatory Capital Requirement, Compliance [Table] Minimum Minimum [Member] Net interest income after provision for (reversal of) for credit losses Interest Income (Expense), after Provision for Loan Loss Interest on investment securities Interest On Investment Securities [Member] Interest On Investment Securities Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Company Selected Measure Name Company Selected Measure Name Fair Value, Disclosure Item Amounts [Domain] Fair Value Measurement [Domain] Total Capital (to risk-weighted assets), Adequately Capitalized Threshold, Amount Banking Regulation, Total Risk-Based Capital, Capital Adequacy, Minimum Borrowings and Other Obligations Debt Disclosure [Text Block] Net losses on sale of investment securities Gain (Loss) on Sale of Investments Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Number of loans past due more than 90 days still accruing Financing Receivable, 90 Days Or More Past Due, Still Accruing, Number Of Loans Financing Receivable, 90 Days Or More Past Due, Still Accruing, Number Of Loans Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Collateral Held [Domain] Collateral Held [Domain] Stockholders' Equity Stockholders' Equity Note [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Share-Based Payment Arrangement, Tranche Two Share-Based Payment Arrangement, Tranche Two [Member] Diluted (in shares) Weighted average diluted common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Interest rate earned on deferred amounts, prime rate first business day of year Deferred Compensation Arrangement with Individual, Deferred Interest Earned, Percent Deferred Compensation Arrangement with Individual, Deferred Interest Earned, Percent Segment Reporting Segment Reporting, Policy [Policy Text Block] Total grant-date fair value of option shares vested Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested in Period, Fair Value Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Home equity Home Equity Loan [Member] Secure public deposits in compliance with the Local Agency Security Program Public Deposits [Member] Pledged assets to secure Public Deposits placed to the institution [Member] Proceeds from bank-owned life insurance policies Proceeds from Life Insurance Policy Smaller Reporting Company Entity Small Business Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] FHLB, special cash dividend percentage Federal Home Loan Bank, Special Cash Dividend Rate, Percentage Federal Home Loan Bank, Special Cash Dividend Rate, Percentage Earnings on bank-owned life insurance, net Bank Owned Life Insurance Income, Net Bank Owned Life Insurance Income, Net Marketable securities, total securities in a loss position, fair value Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total Other Effective Income Tax Rate Reconciliation, Other Tax Exempt Income, Amount Effective Income Tax Rate Reconciliation, Other Tax Exempt Income, Amount State Current State and Local Tax Expense (Benefit) Document Transition Report Document Transition Report Employee Stock Ownership Plan (“ESOP”) Employee Stock Ownership Plan (ESOP), Policy [Policy Text Block] After one but within five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Total minimum lease payments Finance Lease, Liability, to be Paid Underlying Securities Award Underlying Securities Amount Gross realized gains Debt Securities, Available-for-Sale, Realized Gain Marketable securities, greater than 12 continuous months, fair value Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date Income Taxes Income Tax Disclosure [Text Block] Financing Receivable Class Benchmark Financing Receivable Portfolio Benchmark [Member] Financing Receivable Portfolio Benchmark Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Decrease in value of yield maintenance agreement Derivative, Increase (Decrease) in Value of Yield Maintenance Agreement Increase (Decrease) in value of yield maintenance agreement recognized against interest income. Net Amount Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Share repurchased, average post (in dollars per share) Shares Acquired, Average Cost Per Share Risks and Uncertainties [Abstract] Risks and Uncertainties [Abstract] Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] Deferred Compensation Arrangement with Individual, Excluding Share-Based Payments and Postretirement Benefits [Line Items] Accretion of discount on subordinated notes Accretion of discount on subordinated notes Amortization of Debt Discount (Premium) Document Type Document Type Significant Unobservable Inputs (Level 3) Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Name Outstanding Recovery, Individual Name Loss Contingencies [Table] Loss Contingencies [Table] Product and Service [Axis] Product and Service [Axis] Gross current period charge-offs, originated, revolving loans amortized cost Financing Receivable, Excluding Accrued Interest, Revolving, Writeoff Marketable securities, total securities in a loss position, unrealized loss Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss Death benefits provided under terms of the programs Life Insurance, Corporate or Bank Owned, Amount Federal Home Loan Bank Branch [Axis] Federal Home Loan Bank Branch [Axis] Pledged to FHLB Securities-Backed Credit Program FHLB Securities Backed Credit Program [Member] FHLB Securities Backed Credit Program Financial asset, other than financial asset acquired with credit deterioration Financial Asset, Other than Financial Asset Acquired with Credit Deterioration [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] $10.00 - $20.00 Price Range One [Member] Price Range One Loss contingency accrual Loss Contingency Accrual Stock repurchase program, authorized amount Share Repurchase Program, Authorized, Amount Cancelled, expired or forfeited (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Gross current period charge-offs, originated, year two Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff Financing receivable allowance, current Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Current Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Exercised Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value Restricted stock surrendered for tax withholdings upon vesting Restricted stock surrendered for tax withholdings upon vesting Payment, Tax Withholding, Share-Based Payment Arrangement Total pledged investment securities Securities Loaned, Fair Value of Collateral Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Standby letters of credit Financial Standby Letter of Credit [Member] Finance lease cost: Finance Lease Cost1 [Abstract] Finance Lease Cost1 [Abstract] Schedule of Segment Revenue, Profit or Loss, Significant Segment Expenses and Other Segment Items Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Other comprehensive income, net of tax Other comprehensive income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Aggregate Intrinsic Value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract] Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance Derivative Instruments, Gain (Loss) [Table Text Block] Quoted Prices in Active Markets for Identical Assets (Level 1) Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Carrying Value Long-Term Line of Credit Directors' expense Director Fee Related Party Transaction [Table] Related Party Transaction [Table] Diluted (in dollars per share) Diluted EPS (in dollars per share) Earnings Per Share, Diluted Federal Deposit Insurance Corporation insurance Federal Deposit Insurance Corporation Premium Expense Other Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount Related party deposit liabilities Related Party Deposit Liabilities After five years through ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Total Modifications Total Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount Financing receivable allowance (decrease) increase Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Period Increase (Decrease) Number of investment securities in unrealized loss position less than 12 months Marketable Securities In Unrealized Loss Positions, Qualitative Disclosure, Number Of Positions, Less Than 12 Months Marketable Securities In Unrealized Loss Positions, Qualitative Disclosure, Number Of Positions, Less Than 12 Months Potentially dilutive common shares related to: Potentially Dilutive Common Shares Related To [Abstract] Potentially Dilutive Common Shares Related To [Abstract] State Income Tax Paid, State and Local, after Refund Received Securities of U.S. government-sponsored enterprises: Securities Of U.S. Government-Sponsored Enterprises [Abstract] Securities Of U.S. Government-Sponsored Enterprises Community banking segment: Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract] Consolidation Items [Domain] Consolidation Items [Domain] Provision for (reversal of) credit losses on unfunded loan commitments Provision For (Reversal Of) Losses On Unfunded Loan Commitments Provision For (Reversal Of) Losses On Unfunded Loan Commitments Investment securities: Investment securities: Investments, Debt and Equity Securities [Abstract] Auditor Location Auditor Location Core Deposit Intangible Core Deposits [Member] Schedule of Available-for-sale Securities and Held-to-maturity Securities [Table] Schedule of Available-for-sale Securities and Held-to-maturity Securities [Table] Schedule of Available-for-sale Securities and Held-to-maturity Securities [Table] Term Extension Extended Maturity [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Comprehensive Income (Loss) Comprehensive Income, Policy [Policy Text Block] Domestic Tax Jurisdiction Domestic Tax Jurisdiction [Member] Financial Instruments Owned and Pledged as Collateral [Line Items] Financial Instruments Owned and Pledged as Collateral [Line Items] Amounts representing interest (present value discount) Lessee, Operating Lease, Liability, Undiscounted Excess Amount Sales proceeds Proceeds from Sale of Equity Securities, FV-NI Interest received on non-accrual loans Deferred Tax Assets, Interest Received On Nonaccrual Loans Deferred Tax Assets, Interest Received On Nonaccrual Loans Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Data processing Data Processing The amount of expenses incurred in the period for data processing products and services. 2026 Time Deposit Maturities, Year One Income taxes paid, net of refunds Total Income Taxes Paid, Net Corporate bonds Corporate bonds Corporate Bond Securities [Member] 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Two Accrued expenses payable Accrued Liabilities Granted (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Federal home loan bank, dividend rate percentage Federal Home Loan Bank, Dividend Rate, Percentage Federal Home Loan Bank, Dividend Rate, Percentage Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Bank Premises and Equipment Property, Plant and Equipment Disclosure [Text Block] Total minimum lease payments Lessee, Operating Lease, Liability, to be Paid The Bank Subsidiaries [Member] Bank premises and equipment, net Bank premises and equipment, net Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization Marketable Securities, Fair Value Marketable Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Marketable Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Schedule of Capital Adequacy Ratios Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Loans, at amortized cost Total Total loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss Lines of credit Line of Credit Facility, Current Borrowing Capacity Subordinated Notes Subordinated Borrowings Disclosure [Text Block] Number of shares of securities carried at cost (in shares) Investment Owned, Balance, Shares Expiration Date Trading Arrangement Expiration Date Net changes in interest payable and other liabilities Other liabilities Increase (Decrease) in Other Operating Liabilities 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Five Allowance For Credit Loss, Allocation [Domain] Allowance For Credit Loss, Allocation [Domain] Allowance For Credit Loss, Allocation [Domain] Held-to-maturity, allowance for credit Loss Allowance for Credit Losses Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest Exercisable (vested) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Construction Construction Loans [Member] Proceeds from stock issued under employee and director stock purchase plans Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Excluding Option Exercised Entity Current Reporting Status Entity Current Reporting Status Receivables [Abstract] Receivables [Abstract] Dividends from bank subsidiary Dividend Income From Subsidiaries, Operating Dividend Income From Subsidiaries, Operating Total amount withheld (in thousands) Adjustments Related To Tax Withholding And Exercise Of Options For Share-Based Compensation Adjustments Related To Tax Withholding And Exercise Of Options For Share-Based Compensation Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Segment Reporting, Revenue from External Customer, Product and Service [Table] Segment Reporting, Revenue from External Customer, Product and Service [Table] Collateral Held [Axis] Collateral Held [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Loss on contract termination Loss on Contract Termination Within one year Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One Finance leases: Finance Leases [Abstract] Finance Leases [Abstract] Federal statutory income tax rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Other expense Other Noninterest Expense, Adjusted Other Noninterest Expense, Adjusted Type of Deferred Compensation [Axis] Deferred Bonus and Profit Sharing Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Purchase of bank-owned life insurance policies Payment to Acquire Life Insurance Policy, Investing Activities Loss on disposal of premises and equipment Gain (Loss) on Disposition of Property Plant Equipment Financial Instrument [Axis] Financial Instrument [Axis] Deferred tax assets: Deferred Tax Assets, Gross [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Executive Category: Executive Category [Axis] Available-for-sale, greater than 12 continuous months, unrealized loss Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Originated Loans, Acquired Loans, and Past-Due and Non-Accrual Loan Policy Financing Receivable [Policy Text Block] California franchise tax, net of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Noncash contribution expense to employee stock ownership plan Stock issued to employee stock ownership plan Employee Stock Ownership Plan (ESOP), Compensation Expense Low income housing (includes benefits of tax losses, net of amortization Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount Average Balance Line of Credit Facility, Average Outstanding Amount Interest expense Interest Expense, Operating and Nonoperating Current Fiscal Year End Date Current Fiscal Year End Date Expected life in years Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term Available-for-sale, less than 12 continuous months, unrealized loss Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Total deposits Deposits Schedule of Loans by Class Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Weighted Average Grant-Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Number of shares available for future grants under plan (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Federal home loan bank stock Federal Home Loan Bank Stock Professional services Professional Fees Derivative financial liabilities (interest rate contracts) Interest rate contracts fair value, liability derivatives Derivative Liability Other expense Other Noninterest Expense Granted (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Axis] Pass and Watch Pass [Member] Interest Rate Contract Interest Rate Contract [Member] Available-for-sale, total securities in a loss position, unrealized loss Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Directors, Officers, Principal Shareholders and Associates Directors, Officers, Principal Shareholders And Associates [Member] Directors, Officers, Principal Shareholders And Associates [Member] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Dividends on Federal Home Loan Bank stock Dividend Income, Federal Home Loan Bank Dividend Income, Federal Home Loan Bank Weighted average anti-dilutive common shares not included in the calculation of diluted EPS (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Weighted average common shares: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Deferred compensation obligation Deferred Compensation Arrangement with Individual, Recorded Liability Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Collateral Pledged Collateral Pledged [Member] Schedule of Past Due Financing Receivables Financing Receivable, Past Due [Table Text Block] Net cash (used in) provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Measure: Measure [Axis] Thereafter Finite-Lived Intangible Asset, Expected Amortization, after Year Five Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] Debt securities, available-for-sale, accrued interest, after allowance for credit loss, statement of financial position [Extensible Enumeration] Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Installment and other consumer Consumer Portfolio Segment [Member] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Concentration risk, calls and maturities Concentration Risk, Credit Risk, Financial Instrument, Calls And Maturities Concentration Risk, Credit Risk, Financial Instrument, Calls And Maturities Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Issuance costs offset to subordinated notes Amortization of Debt Issuance Costs Risk-free interest rate Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Supplemental disclosure of noncash investing and financing activities: Other Noncash Investing and Financing Items [Abstract] Entity Tax Identification Number Entity Tax Identification Number Gross current period charge-offs, originated, year four Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff Merchant interchange fees, net Merchant Interchange Fees, Net [Member] Merchant Interchange Fees, Net [Member] Options outstanding, beginning balance (in dollars per share) Options outstanding, ending balance (in dollars per share) Weighted Average Exercise Price (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Common stock, issued (in shares) Common Stock, Shares, Issued Derivative Asset, Statement of Financial Position [Extensible Enumeration] Derivative Asset, Statement of Financial Position [Extensible Enumeration] Weighted average remaining term (in years) Operating Lease, Weighted Average Remaining Lease Term CMBS issued by FHLMC, FNMA and GNMA CMBS issued by FHLMC, FNMA and GNMA Commercial Mortgage-Backed Securities [Member] Financing receivable, nonaccrual, earning interest on cash basis Financing Receivable, Nonaccrual, Earning Interest On Cash Basis Financing Receivable, Nonaccrual, Earning Interest On Cash Basis Allowance for Loan and Lease Losses [Roll Forward] Allowance for Loan and Lease Losses [Roll Forward] MBS pass-through securities issued by FHLMC, FNMA and GNMA Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] Entity Public Float Entity Public Float Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Loss Contingencies [Line Items] Loss Contingencies [Line Items] Security Exchange Name Security Exchange Name Total operating lease cost Operating Lease Cost, Net Operating Lease Cost, Net Foreign Income Tax Paid, Foreign, after Refund Received Sale of equity securities: Equity Securities, FV-NI [Abstract] Commercial mortgage-back securities, mortgage-backed securities and collateralized mortgage obligations issued by U.S. government-sponsored agencies Collateralized Mortgage-Backed Securities [Member] Commercial non-owner occupied Commercial real estate, non-owner occupied Commercial Real Estate Loan, Non-Owner Occupied [Member] Commercial Real Estate Loan, Non-Owner Occupied Stock repurchased, including commissions (in shares) Stock repurchased, including commissions (in shares) Stock Repurchased During Period, Shares Deferred loan origination costs and fees Deferred Tax Liabilities, Deferred Loan Origination Costs Deferred Tax Liabilities, Deferred Loan Origination Costs (Increase) decrease in loans receivable, net (Increase) Decrease In Loans Receivable, Net (Increase) Decrease In Loans Receivable, Net Stock-based compensation Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture Statement [Line Items] Statement [Line Items] Held-to-maturity securities pledged as collateral Debt Securities, Held-to-Maturity, Restricted Carrying Amounts of Hedged Assets Hedged Asset, Fair Value Hedge FRBSF short-term borrowings under the BTFP Federal Reserve Bank Term Funding Program [Member] Federal Reserve Bank Term Funding Program Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Undisbursed commitment to related parties Unused Commitments to Extend Credit Transfer of loan to loans held-for-sale Transfer of Loan to Loans Held-for-Sale at Fair Value Transfer of Loan to Loans Held-for-Sale at Fair Value Common Stock Common Stock [Member] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Accrued interest Debt Securities, Held-to-Maturity, Accrued Interest, before Allowance for Credit Loss Finance Leases Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Net (decrease) increase in cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Cash dividends paid on common stock (in dollars per share) Cash dividends per common share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] The 2017 Equity Plan The 2017 Equity Plan [Member] The 2017 Equity Plan [Member] Statistical Measurement [Domain] Statistical Measurement [Domain] Unallocated Unallocated Financing Receivables [Member] Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Five Schedule of Condensed Balance Sheet Condensed Balance Sheet [Table Text Block] Available-for-sale, amortized cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss Purchase accounting adjustments Deferred Tax Liabilities, Purchase Accounting Adjustments Deferred Tax Liabilities, Purchase Accounting Adjustments Other Effective Income Tax Rate Reconciliation, Other Tax Exempt Income, Percent Effective Income Tax Rate Reconciliation, Other Tax Exempt Income, Percent Nonaccrual interest income Financing Receivable, Nonaccrual, Interest Income Time deposits of more than $250 thousand Time Deposits, $250,000 Or More The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $250,000 or more. Interest Rate Swap Interest Rate Swap [Member] Earnings on bank-owned life insurance death benefits Earnings on bank-owned life insurance death benefits Earnings On Bank-Owned Life Insurance Death Benefits Earnings On Bank-Owned Life Insurance Death Benefits Bank-owned life insurance Bank Owned Life Insurance Held-to-maturity, total securities in a loss position, fair value Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value Schedule of Cash Dividends Paid to Common Shareholders Dividends Declared [Table Text Block] Non-accrual loans with no allowance Financing Receivable, Excluding Accrued Interest, Nonaccrual, No Allowance All other loss Other Non-Segment Income (Loss) Other Non-Segment Income (Loss) Retirement Plan Name [Axis] Retirement Plan Name [Axis] Restricted stock surrendered for tax withholdings upon vesting Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Marketable securities, greater than 12 continuous months, unrealized loss Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Basic (in dollars per share) Basic EPS (in dollars per share) Earnings Per Share, Basic Total unfunded loan commitments and standby letters of credit Off-balance Sheet Arrangements, Liabilities, Current Exposure Off-balance Sheet Arrangements, Liabilities, Current Exposure Total gross deferred tax assets Deferred Tax Assets, Gross Threshold period a past due loan is charged off Financing Receivable, Threshold Period Past Due, Writeoff Schedule of Defined Contribution Plans Disclosures [Table] Schedule of Defined Contribution Plans Disclosures [Table] Schedule of Defined Contributions Plans Disclosures [Table] 2030 Time Deposit Maturities, Year Five Time deposits Deposits, Fair Value Disclosure Gross unrealized gains Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain (Accretion of discounts) amortization of premiums on acquired loans, net Accretion Of Discount On Acquired Loans The sum of the periodic adjustments of the difference between the contractual amounts due (principal amount) and the fair value accounted for subsequent to acquisition through accretion. CMOs issued by FHLMC, FNMA and GNMA CMOs issued by FHLMC, FNMA and GNMA Collateralized Mortgage Obligations [Member] Increase (decrease) in fair value of interest rate swaps hedging available-for-sale securities Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments 2028 Finance Lease, Liability, to be Paid, Year Three Commercial and industrial Commercial And Industrial [Member] Commercial And Industrial [Member] Gross current period charge-offs, originated, total Charge off of allowance for credit loss (Charge-offs) Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Reclassification adjustment for gains or losses for fair value hedges Other Comprehensive Income (loss), Reclassification Adjustment, Gain or Losses Fair Value Hedge Other Comprehensive Income (loss), Reclassification Adjustment, Gain or Losses Fair Value Hedge Accounts and Financing Receivables [Table] Accounts and Financing Receivables [Table] Transaction accounts Deposits, Negotiable Order of Withdrawal (NOW) Total compensation cost for share-based payment arrangements Share-Based Payment Arrangement, Expense Hedging Designation [Domain] Hedging Designation [Domain] Financing receivable, accrued interest, net Financing Receivable, Accrued Interest, after Allowance for Credit Loss Bank Owned Life Insurance Life Insurance, Corporate or Bank Owned [Text Block] Total liabilities and stockholders' equity Liabilities and Equity Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Stock issued under employee stock ownership plan (in shares) Stock Issued During Period, Shares, Employee Stock Ownership Plan Weighted-average price (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Tax Withholding And Exercises in Period, Weighted Average Exercise Price Share-based Compensation Arrangements by Share-based Payment Award, Options, Tax Withholding And Exercises in Period, Weighted Average Exercise Price Other Deferred Tax Assets, Other Collateral for Wealth Management and Trust Services checking account Checking account, Wealth Management and Trust Services [Member] Pledged assets to secure Checking account, Wealth Management and Trust Services [Member] Liability under the salary continuation plan Liability, Defined Benefit Plan Debt Securities, Held-to-maturity, Credit Quality Indicator [Table] Debt Securities, Held-to-Maturity, Credit Quality Indicator [Table] Equity Method Investment [Table] Equity Method Investment [Table] Investments in Low Income Housing Tax Credit Funds Affordable Housing Program, Policy [Policy Text Block] Affordable Housing Program, Policy [Policy Text Block] Gross Amounts Not Offset in the Statements of Condition, Financial Instruments Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Security Not Offset Accounting Policies [Abstract] Accounting Policies [Abstract] Additions Loans and Leases Receivable, Related Parties, Additions Concentration Risk Type [Domain] Concentration Risk Type [Domain] Financing receivable, originated, year one Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year Pay vs Performance Disclosure [Line Items] Proceeds in excess of the cash surrender values Proceeds In Excess Of Cash Surrender Values On Bank-Owned Life Insurance Proceeds In Excess Of Cash Surrender Values On Bank-Owned Life Insurance Tier 1 Leverage Capital (to average assets), Threshold to be a Well Capitalized Bank Holding Company, Ratio Banking Regulation, Tier 1 Leverage Capital Ratio, Well Capitalized, Minimum Write-down of other real estate owned Write-Down Of Other Real Estate Owned Write-Down Of Other Real Estate Owned Operating lease liabilities Operating lease liabilities Present value of net minimum lease payments (lease liability) Operating Lease, Liability 90 Days or More Past Due Financial Asset, Equal to or Greater than 90 Days Past Due [Member] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Liabilities Liabilities [Abstract] Amortization of right-of-use assets Finance Lease, Right-of-Use Asset, Amortization Other Real Estate Owned ("OREO") Real Estate, Policy [Policy Text Block] Interest on interest-bearing transaction accounts Interest Expense, Negotiable Order of Withdrawal (NOW) Deposits Common Equity Tier 1 (to risk-weighted assets), Actual, Amount Tier One Common Equity Tier One Common Equity Range of Exercise Prices, Upper Limit (in dollars per share) Share-Based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit Goodwill impairment Goodwill, Impairment Loss Regulatory Matters Regulatory Capital Requirements under Banking Regulations [Text Block] Employer matching contribution maximum amount Defined Contribution Plan, Employer Matching Contribution, Maximum Amount Defined Contribution Plan, Employer Matching Contribution, Maximum Amount Financing receivable, originated, year three Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount 2028 Lessee, Operating Lease, Liability, to be Paid, Year Three Cash held Cash Gross current period charge-offs, originated, prior Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year, Writeoff Tier 1 Capital (to risk-weighted assets), Threshold to be a Well Capitalized Bank Holding Company, Ratio Banking Regulation, Tier 1 Risk-Based Capital Ratio, Well Capitalized, Minimum Total comprehensive (loss) income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Name Measure Name Payment period determined by service period Defined Benefit Plan, Payment Period Determined By Service Period Defined Benefit Plan, Payment Period Determined By Service Period Schedule of Pretax Income from Continuing Operations Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Within one year Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Tier 1 Capital (to risk-weighted assets), Threshold to be a Well Capitalized Bank Holding Company, Amount Tier One Risk Based Capital Required For Capital Adequacy With Buffer Tier One Risk Based Capital Required For Capital Adequacy With Buffer Aaa / AAA Moody's And/Or Standard & Poor's AAA Rating [Member] Moody's And/Or Standard & Poor's AAA Rating Decrease (increase) in carrying value included in the hedged available-for-sale securities Decrease (Increase) In Fair Value Of Hedged Item in Interest Rate Fair Value Hedge Decrease (Increase) In Fair Value Of Hedged Item in Interest Rate Fair Value Hedge Net increase (decrease) in deposits Increase (Decrease) in Deposits Proceeds from paydowns/maturities of available-for-sale securities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Commercial lines of credit Commercial Lines of Credit [Member] Commercial Lines of Credit [Member] Officers and Employees Officers And Employees [Member] Officers And Employees Restatement of Prior Period Financial Statements (Quarterly Information Unaudited) Error Correction [Text Block] Unsecured Debt Unsecured Debt [Member] $40.01 - $50.00 Price Range Four [Member] Price Range Four [Member] Total assets Assets Schedule of Condensed Cash Flow Statement Condensed Cash Flow Statement [Table Text Block] 2026 Finite-Lived Intangible Asset, Expected Amortization, Year One Minimum age of eligible employee for 401(k) plan Defined Contribution Plan, Minimum Age of Eligible Employee Defined Contribution Plan, Minimum Age of Eligible Employee Vested (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Financing Receivable, Credit Quality Indicator [Line Items] Financing Receivable, Credit Quality Indicator [Line Items] Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Management Management [Member] Geographical [Domain] Geographical [Domain] Income Taxes Income Tax, Policy [Policy Text Block] Finance lease, initial contract terms (in years) Lessee, Finance Lease, Term of Contract Cash Flows from Operating Activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Number of commercial banking offices Number Of Commercial Banking Offices Number Of Commercial Banking Offices Other Other Collateral Held [Member] Other Collateral Held Concentration Risk Type [Axis] Concentration Risk Type [Axis] Reclassified due to a change in borrower status Loans and Leases Receivable, Reclassified Due To Change In Borrower Status Loans and Leases Receivable, Reclassified Due To Change In Borrower Status Net change in deferred loan origination costs/fees Amortization of Deferred Loan Origination Fees, Net 2027 Time Deposit Maturities, Year Two 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Four Total Capital (to risk-weighted assets), Adequately Capitalized Threshold, Ratio Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum Fair Value Total Investment securities held-to-maturity Debt Securities, Held-to-Maturity, Fair Value Interest on savings accounts Interest Expense, Savings Deposits 2026 Finance Lease, Liability, to be Paid, Year One Dividends declared per common share (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Right-of-use assets obtained in exchange for operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] After five years through ten years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Document Financial Statement Error Correction Document Financial Statement Error Correction [Flag] California franchise tax, net of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount (Loss) earnings of bank subsidiary greater (less) than dividends received from bank subsidiary Equity in Undistributed Net Income of Subsidiary Equity in Undistributed Net Income of Subsidiary Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Operating Leases Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Approved payroll deduction to purchase shares, percentage Share-based Compensation Arrangement by Share-based Payment Award, Approved Payroll Deduction to Purchase Shares, Percentage Share-based Compensation Arrangement by Share-based Payment Award, Approved Payroll Deduction to Purchase Shares, Percentage Schedule of Components of Income Tax Provision Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Allowance for credit losses on loans and unfunded loan commitments Deferred Tax Asset, Tax Deferred Expense, Reserve and Accrual, Accounts Receivable, Allowance for Credit Loss Pledged to the Federal Reserve Discount Window FRBSF advances - Discount Window FRBSF Advances - Discount Window [Member] FRBSF Advances - Discount Window Plan Name [Axis] Plan Name [Axis] Premises and Equipment Property, Plant and Equipment, Policy [Policy Text Block] PEO PEO [Member] Tier 1 Leverage Capital (to average assets), Amount, Actual Banking Regulation, Tier 1 Leverage Capital, Actual Schedule of Investments Classified by Contractual Maturity Date Investments Classified by Contractual Maturity Date [Table Text Block] Core deposit intangible assets Deferred Tax Liabilities, Intangible Assets Defined Contribution Plan Disclosure [Line Items] Schedule of Defined Contribution Plans Disclosures [Line Items] Schedule of Defined Contribution Plans Disclosures [Line Items] Commercial Loan, Non-Owner-Occupied, Acquired Commercial Loan, Non-Owner-Occupied, Acquired [Member] Commercial Loan, Non-Owner-Occupied, Acquired Net changes in: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Modeled expected credit losses Modeled Expected Credit Losses [Member] Modeled Expected Credit Losses Expected price volatility Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Time accounts Total time deposits Time Deposits Retained Earnings Retained Earnings [Member] Income Tax Jurisdiction [Axis] Income Tax Jurisdiction [Axis] Net unrealized losses on securities available-for-sale Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Net Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Net Income Statement [Abstract] Income Statement [Abstract] Cash, cash equivalents and restricted cash Cash, cash equivalents and restricted cash at beginning of period Cash, cash equivalents and restricted cash at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Derivative financial assets (interest rate contracts) Interest rate contracts fair value, asset derivatives Derivative Asset Cash paid for low income housing tax credit investment Payment for Acquisition, Real Estate, Held-for-Investment Available-for-sale, greater than 12 continuous months, fair value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Financing Receivable, Troubled Debt Restructuring [Table] Financing Receivable, Modified [Table] Provision for (reversal of) credit losses on unfunded loan commitments Reversal of credit losses on unfunded loan commitments Provision (reversal) of credit losses on unfunded loan commitments Off-Balance-Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal) Product and Service [Domain] Product and Service [Domain] Customer Concentration Risk Customer Concentration Risk [Member] Allowance For Credit Loss, Allocation [Axis] Allowance For Credit Loss, Allocation [Axis] Allowance For Credit Loss, Allocation Exercisable (vested), ending balance (in dollars per shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Derivative notional amount Derivative, Notional Amount Tax-exempt interest, net of TEFRA Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Revolving Loans Amortized Cost Financing Receivable, Excluding Accrued Interest, Revolving Percentage of commitments expiring in 2026 Loan Commitments and Standby Letters of Credit, Percentage Expiring in Next Twelve Months Loan Commitments and Standby Letters of Credit, Percentage Expiring in Next Twelve Months Title of 12(g) Security Title of 12(g) Security City Area Code City Area Code Schedule of Allowance for Credit Losses on Financing Receivables Financing Receivable, Allowance for Credit Loss [Table Text Block] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Interest on money market accounts Interest Expense, Money Market Deposits Credit Rating, Moody's And/Or Standard & Poor's [Domain] Credit Rating, Moody's And/Or Standard & Poor's [Domain] Credit Rating, Moody's And/Or Standard & Poor's SBA-backed securities Small Business Administration (SBA) Backed Securities [Member] Small Business Administration (SBA) Backed Securities [Member] Cash Flows from Investing Activities: Cash Flows from Investing Activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] General Business Tax Credit Carryforward, Low Income Housing Credits General Business Tax Credit Carryforward, Low Income Housing Credits Carryforward [Member] General Business Tax Credit Carryforward, Low Income Housing Credits Carryforward Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Employer matching contribution percentage Defined Contribution Plan, Employer Matching Contribution, Percent of Match Fair Value Hedge Fair Value Hedging [Member] Annual vesting percentage Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage Total lease cost Lease, Cost Effective Income Tax Rate Reconciliation [Line Items] Effective Income Tax Rate Reconciliation [Line Items] Interest payable and other liabilities Other Liabilities Goodwill Goodwill Schedule of Components of Operating and Finance Lease Cost Lease, Cost [Table Text Block] Deposit network fees Deposit Network Fees Deposit Network Fees Federal Deferred Federal Income Tax Expense (Benefit) Loans Secured by Real Estate Real Estate Loan [Member] Wealth Management and Trust Services Segment Wealth Management And Trust Services Segment [Member] Wealth Management And Trust Services Segment Auditor Name Auditor Name Concentration Risk [Table] Concentration Risk [Table] Equipment Equipment [Member] Fair value adjustment on acquired loans Deferred Tax Asset, Fair Value Adjustment, Loans Receivable Deferred Tax Asset, Fair Value Adjustment, Loans Receivable Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Revenue from External Customer [Line Items] Revenue from External Customer [Line Items] Debt Securities, Available-For-Sale, Fair Value Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] Other Performance Measure, Amount Other Performance Measure, Amount U.S. Government, its agencies and Government Sponsored Enterprises (GSEs) US Treasury and Government [Member] Weighted Average Exercise Price Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Related Party [Domain] Related and Nonrelated Parties [Domain] Concentration risk, purchases Concentration Risk, Credit Risk, Financial Instrument, Purchases Concentration Risk, Credit Risk, Financial Instrument, Purchases Amount Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract] Credit Concentration Risk Credit Concentration Risk [Member] Equity securities, FV-NI gain Equity Securities, FV-NI, Gain (Loss) Derivative Instrument [Axis] Derivative Instrument [Axis] Vesting [Axis] Vesting [Axis] Financial liabilities (recorded at amortized cost) Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Earnings Per Share, Basic and Diluted [Abstract] Earnings Per Share Reconciliation [Abstract] Commercial Real Estate Loans Commercial Real Estate Loans Commercial Real Estate Portfolio Segment [Member] Credit Loss Status [Axis] Credit Loss Status [Axis] Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Interest paid on deposits and borrowings Interest Paid, Excluding Capitalized Interest, Operating Activity Document Fiscal Year Focus Document Fiscal Year Focus Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Lender Name [Axis] Lender Name [Axis] Operating lease right-of-use assets Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Taxes at effective rate Effective Income Tax Rate Reconciliation, Percent Operating lease cost Operating Lease, Cost Equity Method Investment, Nonconsolidated Investee [Axis] Equity Method Investment, Nonconsolidated Investee [Axis] Carrying Value Carrying Amounts Reported Value Measurement [Member] Plan Name [Domain] Plan Name [Domain] Period for recognizing unrecognized compensation expense Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Exercised (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Wealth management and trust services Fiduciary and Trust [Member] Valuation allowance of deferred tax assets Deferred Tax Assets, Valuation Allowance Equity [Abstract] Equity [Abstract] Goodwill and Other Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Buildings Building [Member] Operating leases: Operating Leases [Abstract] Operating Leases [Abstract] Net losses on sale of investment securities Debt and Equity Securities, Gain (Loss) Derivative Financial Instruments and Hedging Activities - Fair Value Hedges Derivatives, Policy [Policy Text Block] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] U.S. Treasury securities US Treasury Securities [Member] Income before equity in undistributed net income of subsidiary Income Before Equity In Undistributed Earnings Of Subsidiaries Represents income before equity in undistributed earnings of subsidiaries. Federal Current Federal Tax Expense (Benefit) Carrying Value Debt and Lease Obligation Investment in bank subsidiary Investment in Subsidiary Investment in Subsidiary Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Debt Securities, Available-for-sale, Unrealized Loss Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Common Equity Tier 1 (to risk-weighted assets), Adequately Capitalized Threshold, Ratio Tier One Common Equity Required for Capital Adequacy to Average Assets Tier One Common Equity Required for Capital Adequacy to Average Assets Collateral Asset Type Concentration Risk Collateral Asset Type Concentration Risk [Member] Collateral Asset Type Concentration Risk Other obligations (finance leases) Other Debt Obligations [Member] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Financing receivable, unamortized loan fee Financing Receivable, Unamortized Loan Cost (Fee) Marketable securities, less than 12 continuous months, unrealized loss Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Available-for-sale Securities and Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Leases Lessee, Leases [Policy Text Block] Amortization of core deposit intangible Amortization of core deposit intangible Amortization of Intangible Assets Loans receivable: Loans Receivable [Member] Proceeds from sale of loan Proceeds from Sale of Loans Receivable Stock repurchased, including commissions Stock repurchased Stock Repurchased During Period, Value 2035 Notes 2035 Notes [Member] 2035 Notes Issuance costs offset to subordinated notes Issuance Costs Offset To Subordinated Notes Issuance Costs Offset To Subordinated Notes Weighted average ratio of loans value to collateral dependent loans value Weighted Average Ratio Of Loans Value To Collateral Dependent Loans Value Weighted Average Ratio Of Loans Value To Collateral Dependent Loans Value Finance lease liabilities Carrying Value Present value of net minimum lease payments (lease liability) Finance Lease, Liability Arrangement Duration Trading Arrangement Duration Segments [Axis] Segments [Axis] San Francisco San Francisco [Member] San Francisco Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Affordable housing tax credits, investment, ownership percentage Affordable Housing Tax Credits, Investment, Ownership Percentage Affordable Housing Tax Credits, Investment, Ownership Percentage Interest receivable and other assets Interest Receivable and Other Assets Discount from closing market price at end of each quarter Share-Based Compensation Arrangement by Share-Based Payment Award, Discount from Market Price, Purchase Date Average Rate Finance Lease Liability, Average Interest Rate Finance Lease Liability, Average Interest Rate Estimated death benefits Life Insurance, Corporate or Bank Owned, Death Benefits Life Insurance, Corporate or Bank Owned, Death Benefits Unfunded commitments totaled Off-Balance-Sheet, Credit Loss, Liability Assets Assets Assets [Abstract] Credit Facility [Axis] Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Debt Instrument [Axis] Debt Instrument [Axis] Balance at beginning of year Balance at end of year Loans and Leases Receivable, Related Parties Cancelled or forfeited (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Fair Value of Assets and Liabilities Fair Value Disclosures [Text Block] Common Equity Tier 1 (to risk-weighted assets), Adequately Capitalized Threshold, Amount Tier One Common Equity Required for Capital Adequacy Tier One Common Equity Required for Capital Adequacy Credit Facility [Domain] Credit Facility [Domain] Stockholders' Equity Equity, Attributable to Parent [Abstract] FHLB fixed-rate advances FHLB Fixed-Rate Advances [Member] FHLB Fixed-Rate Advances Vesting percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Repayments Loans and Leases Receivable, Related Parties, Proceeds FHLB short-term borrowings Federal Home Loan Bank Borrowings [Member] Loans and Leases Receivable, Related Parties [Roll Forward] Loans and Leases Receivable, Related Parties [Roll Forward] Schedule of Troubled Debt Restructurings on Financing Receivables Financing Receivable, Modified [Table Text Block] Fixed interest rate Debt Instrument, Interest Rate, Stated Percentage Investment, Name [Axis] Investment, Name [Axis] 30-59 days past due Financial Asset, 30 to 59 Days Past Due [Member] Entity Voluntary Filers Entity Voluntary Filers Reconciliation of segment (loss) income Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract] Earnings of bank subsidiary less (greater) than dividends received from bank subsidiary Equity in Undistributed and Distributed Earnings of Subsidiary, Net of Dividends Received Equity in Undistributed and Distributed Earnings of Subsidiary, Net of Dividends Received Gross Amounts of Recognized Assets Derivative Asset, Subject to Master Netting Arrangement, before Offset Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Entity Registrant Name Entity Registrant Name Retirement Plan Name [Domain] Retirement Plan Name [Domain] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Total Capital (to risk-weighted assets), Threshold to be a Well Capitalized Bank Holding Company, Ratio Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum Undisbursed construction loans Undisbursed Construction Loans [Member] Undisbursed Construction Loans [Member] Exercisable (vested), ending balance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number Revision of Prior Period [Domain] Revision of Prior Period [Domain] Deposits: Deposits: Deposits [Abstract] Total past due Financial Asset, Past Due [Member] Finance lease right-of-use assets Finance lease right-of-use assets Finance Lease, Right-of-Use Asset, before Accumulated Amortization Number of operating segments Number of Operating Segments Amortization of investment security premiums, net of accretion of discounts Accretion (Amortization) of Discounts and Premiums, Investments Schedule of Debt Schedule of Debt [Table Text Block] Operating and finance lease right-of-use assets Operating Lease And Finance Lease, Right-Of-Use Asset Operating Lease And Finance Lease, Right-Of-Use Asset Granted (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 Related Party [Axis] Related and Nonrelated Parties [Axis] Number of consecutive payments considered sustained repayment performance Loans and Leases Receivable, Nonperforming, Number Of Consecutive Payments Considered Sustained Repayment Performance Loans and Leases Receivable, Nonperforming, Number Of Consecutive Payments Considered Sustained Repayment Performance Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Percent [Abstract] Held-to-maturity, less than 12 continuous months, fair value Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value Restatement Determination Date: Restatement Determination Date [Axis] Foreign Deferred Foreign Income Tax Expense (Benefit) The Plan, 2020 The Plan, 2020 [Member] The Plan, 2020 Name Trading Arrangement, Individual Name As Previously Reported Previously Reported [Member] Principal amount Debt Instrument, Face Amount Interest on borrowings and other obligations Interest Expense, Borrowings and Other Obligations Interest Expense, Borrowings and Other Obligations Maximum percentage of compensation allowed to be deferred Deferred Compensation Arrangement with Individual, Maximum Elected Deferral by Employee, Percent Deferred Compensation Arrangement with Individual, Maximum Elected Deferral by Employee, Percent Depreciation and disposals on premises and equipment Deferred Tax Assets, Property, Plant and Equipment Concentration risk, sales offset Concentration Risk, Credit Risk, Financial Instrument, Sales Offset Concentration Risk, Credit Risk, Financial Instrument, Sales Offset All other income Other Income (Loss), Segment Reconciliation Other Income (Loss), Segment Reconciliation Specific allocations Specific Allocations [Member] Specific Allocations Weighted Average Remaining Contractual Term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract] Name Awards Close in Time to MNPI Disclosures, Individual Name Non-vested awards, beginning balance (in dollars per share) Non-vested awards, ending balance (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Interest receivable Interest Receivable, Fair Value Disclosure This element represents the disclosures for fair value estimates for financial instruments required in the footnote disclosures to the financial statements. Carrying amount represents interest earned but not received from loan borrowers, investment security issuers and on other forms of short-term investment for time value of money. The carrying value may approximate fair value due to the short-term nature of their settlement dates. ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Federal home loan bank stock, par value (in dollars per share) Federal Home Loan Bank Stock, Par Value Federal Home Loan Bank Stock, Par Value Schedule of Finance Lease Liability Maturities Finance Lease, Liability, to be Paid, Maturity [Table Text Block] Schedule of Time Deposits Schedule of Time Deposits [Table Text Block] Schedule of Time Deposits [Table Text Block] Schedule of Condensed Income Statement Condensed Income Statement [Table Text Block] Auditor Firm ID Auditor Firm ID Credit Loss Status [Domain] Credit Loss Status [Domain] Segments [Domain] Segments [Domain] Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Bank of Marin Employee Stock Ownership and Savings Plan (the Plan) Bank of Marin Employee Stock Ownership and Savings Plan [Member] Bank of Marin Employee Stock Ownership and Savings Plan (the Plan) [Member] Investment Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Collateral Dependent Loans Collateral Dependent Loans [Policy Text Block] Collateral Dependent Loans Statement of Financial Position Location, Balance [Domain] Statement of Financial Position Location, Balance [Domain] Federal Reserve Bank Federal Reserve Bank [Member] Federal Reserve Bank Gross Amounts Not Offset in the Statements of Condition, Cash Collateral Received Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Other, tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent Interest expense Interest Expense, Operating and Nonoperating [Abstract] Earnings per share (“EPS”) Earnings Per Share, Policy [Policy Text Block] Community Banking Segment Community Banking Segment [Member] Community Banking Segment Schedule of Unrealized Loss on Investments Debt Securities, Available-For-Sale And Held-To-Maturity, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Debt Securities, Available-For-Sale And Held-To-Maturity, Continuous Unrealized Loss Position, Fair Value Gross Amounts Offset in the Statements of Condition Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Purchase of available-for-sale securities Payments to Acquire Debt Securities, Available-for-Sale Income Operating Income (Loss) [Abstract] Preferred stock, no par value, Authorized - 5,000,000 shares, none issued Preferred Stock, Value, Issued Obligations of state and political subdivisions Obligations of state and political subdivisions US States and Political Subdivisions Debt Securities [Member] Finance lease right-of-use assets Finance Lease Right-Of-Use Assets [Member] Finance Lease Right-Of-Use Assets Weighted Average Grant-Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Grant-Date Fair Value [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Grant-Date Fair Value [Roll Forward] Available-for-sale Securities, Fair Value Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Subordinated notes, net of issuance costs Carrying Value Subordinated notes Subordinated Debt Financing receivable, originated, year two Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year Held-to-maturity Securities, Fair Value Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Subordinated Notes Subordinated notes Subordinated Debt [Member] Financial Asset, Period Past Due [Axis] Financial Asset, Aging [Axis] All Executive Categories All Executive Categories [Member] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Common stock, no par value, Authorized - 30,000,000 shares; Issued and outstanding - 16,102,687 and 16,089,454 at December 31, 2025 and 2024, respectively Common Stock, Value, Issued Finance lease right-of-use assets, net Finance Lease, Right-of-Use Asset, after Accumulated Amortization Interest and fees on loans Interest and Fee Income, Loans and Leases Title and Position [Axis] Title and Position [Axis] Schedule of Sale of Investment Securities and Gross Gains and Losses Realized Gain (Loss) on Investments [Table Text Block] Commitments and contingent liabilities (Note 12 and 17) Commitments and Contingencies Gross current period charge-offs, originated, year one Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year, Writeoff Net changes in: Net Changes In [Abstract] Net Changes In Concentration risk amount Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure Salaries and employee benefits Labor And Related Expense, Adjusted Labor And Related Expense, Adjusted Concentration Risk [Line Items] Concentration Risk [Line Items] Restricted Stock And Options Restricted Stock And Options [Member] Restricted Stock And Options Net deferred tax assets Net deferred tax assets Deferred Tax Assets, Net Other Ownership Interests [Line Items] Other Ownership Interests [Line Items] Number of investment securities in unrealized loss position Marketable Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Marketable Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount After ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Depreciation and amortization Depreciation, Depletion And Amortization, Nonproduction, Excluding Amortization Of Intangible Assets, Adjusted Depreciation, Depletion And Amortization, Nonproduction, Excluding Amortization Of Intangible Assets, Adjusted Loan Charge-Off Policy Financing Receivable, Charge-offs, Policy [Policy Text Block] Loans and Leases Receivable, Charge-offs, Policy [Policy Text Block] Annual Salary Annual Salary [Member] Annual Salary [Member] Cancelled, expired or forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period Stock issued to ESOP Stock Issued In Payment Of Director Fees And To ESOP Stock Issued In Payment Of Director Fees And To ESOP 60-89 days past due Financial Asset, 60 to 89 Days Past Due [Member] Hedging Designation [Axis] Hedging Designation [Axis] Bankruptcy trustee deposits pledged with Federal Reserve Bank Bankruptcy Trustee Deposits Pledged With Federal Reserve Bank [Member] Bankruptcy Trustee Deposits Pledged With Federal Reserve Bank Deferred Bonus Deferred Bonus [Member] Net Amount Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction California CALIFORNIA Number of instruments held Derivative, Number of Instruments Held Derivative Contract [Domain] Derivative Contract [Domain] Financing Receivable, Allowance for Credit Loss [Table] Financing Receivable, Allowance for Credit Loss [Table] Gross realized losses Debt Securities, Available-for-Sale, Realized Loss After ten years Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 10 All Individuals All Individuals [Member] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Residential Real Estate Residential Real Estate [Member] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Purchase of premises and equipment Payments to Acquire Property, Plant, and Equipment Name Forgone Recovery, Individual Name Expiration period of grants Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Collateral for trust deposits Trust Deposits [Member] Pledged assets to secure Trust Deposits placed in the institution [Member] Average Rate Debt, Weighted Average Interest Rate Deposit overdrafts reclassified as loan balances Deposit Liabilities Reclassified as Loans Receivable Error Corrections and Prior Period Adjustments Restatement [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Low income housing (includes benefits of tax losses, net of amortization Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent Occupancy and equipment Occupancy And Equipment, Adjusted Occupancy And Equipment, Adjusted Available-for-sale Securities, Amortized Cost Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract] Percentage of salary paid upon retirement Defined Benefit Plan, Percentage of Salary Paid upon Retirement Defined Benefit Plan, Percentage of Salary Paid upon Retirement Gross current period charge-offs, originated, year five Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff Interest payable Interest Payable, Fair Value Disclosure This element represents the disclosures for fair value estimates for financial instruments required in the footnote disclosures to the financial statements. Carrying amount represents accrued interest payable on all forms of debt, including deposit liabilities, that has been incurred and is unpaid for time value of money. The carrying value may approximate fair value due to the short-term nature of their settlement dates. Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Intangible Asset, Finite-Lived [Table] Intangible Asset, Finite-Lived [Table] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Geographical [Axis] Geographical [Axis] Held-to-maturity, total securities in a loss position, unrealized loss Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss Commercial Portfolio Segment Commercial and industrial Commercial Portfolio Segment [Member] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Tax credit carryforwards Deferred Tax Assets, Tax Credit Carryforwards Non-Employee Directors Non-Employee Directors [Member] Non-Employee Directors Federal Home Loan Bank of San Francisco Federal Home Loan Bank of San Francisco [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Interest on investment securities Interest Income, Operating Exercisable (vested), ending balance Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Provision for credit losses on loans Provision for credit losses on loans (Reversal) provision Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal) Stock issued in payment of director fees Stock issued in payment of director fees Stock Issued In Payment Of Director Fees Dollar amount of common stock issued by an Entity to its directors in payment of services they render. Net (loss) income per common share: Earnings Per Share [Abstract] 2030 Lessee, Operating Lease, Liability, to be Paid, Year Five Depreciation and amortization Depreciation and amortization Depreciation, Depletion And Amortization, Nonproduction, Excluding Amortization Of Intangible Assets Depreciation, Depletion And Amortization, Nonproduction, Excluding Amortization Of Intangible Assets Defined Contribution Plan (the 401k Plan) Defined Contribution Plan (the 401k Plan) [Member] Defined Contribution Plan (the 401k Plan) [Member] Bank Owned Life Insurance ("BOLI") Life Insurance, Corporate or Bank Owned, Policy [Policy Text Block] Life Insurance, Corporate or Bank Owned, Policy [Policy Text Block] Tax credit carryforward Tax Credit Carryforward, Amount Gross current period charge-offs, originated, year three Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff Short-term Debt, Type [Axis] Short-Term Debt, Type [Axis] Concentration risk, threshold for major borrower, percentage Concentration Risk, Percentage, Threshold For Major Borrower Concentration Risk, Percentage, Threshold For Major Borrower Qualitative adjustments Qualitative Adjustments [Member] Qualitative Adjustments Nonaccrual collateral dependent loans in process of foreclosure Financing Receivable, Nonaccrual, In Process Of Foreclosure Financing Receivable, Nonaccrual, In Process Of Foreclosure Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Thereafter Finance Lease, Liability, to be Paid, after Year Five Exercised (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Proceeds from sale of available-for-sale securities Proceeds From Sale Of Debt Securities, Available-For-Sale, Excluding Transfers From Held-To-Maturity Proceeds From Sale Of Debt Securities, Available-For-Sale, Excluding Transfers From Held-To-Maturity Award Timing Disclosures [Line Items] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Measurement Frequency [Domain] Measurement Frequency [Domain] Federal funds lines of credit Federal Home Loan Bank Advances [Member] Stockholders' Equity and Stock Plans Equity [Text Block] Visa Inc. Class B common stock Visa Inc. Class B Common Stock [Member] Visa Inc. Class B Common Stock [Member] Increase (decrease) in carrying value included in the hedged loans Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge State Deferred State and Local Income Tax Expense (Benefit) Loan Restructuring Modification [Domain] Loan Restructuring Modification [Domain] Loans, net of allowance for credit losses on loans Loans, net of allowance for credit losses on loans Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss Net (loss) income Net income (loss) Net (loss) income Total consolidated income Net Income (Loss) Attributable to Parent Professional services Professional Fees, Adjusted Professional Fees, Adjusted Equity Method Investment, Nonconsolidated Investee [Domain] Equity Method Investment, Nonconsolidated Investee [Domain] Total Capital (to risk-weighted assets), Actual, Ratio Banking Regulation, Total Risk-Based Capital Ratio, Actual Schedule of Effective Income Tax Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Award vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Other adjustments Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Preferred stock, authorized (in shares) Preferred Stock, Shares Authorized Adoption Date Trading Arrangement Adoption Date Total unfunded loan commitments and standby letters of credit Lines of Credit and Letters of Credit, Unused Commitments [Member] Lines of Credit and Letters of Credit, Unused Commitments [Member] Accounting Changes and Reclassifications Reclassification, Comparability Adjustment [Policy Text Block] Segment (loss) income Operating Income (Loss) Line of Credit Line of Credit [Member] Schedule of Offsetting Liabilities Offsetting Liabilities [Table Text Block] Retained earnings Retained Earnings (Accumulated Deficit) Money market accounts Deposits, Money Market Deposits Residential Portfolio Segment Residential Loans Residential Portfolio Segment [Member] $20.01 - $30.00 Price Range Two [Member] Price Range Two [Member] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Class of Stock [Axis] Class of Stock [Axis] Adjustment Revision of Prior Period, Error Correction, Adjustment [Member] Maximum annual contribution per employee, percent of eligible compensation Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Subsequent Event Type [Domain] Subsequent Event Type [Domain] Impairment of intangible assets Impairment of Intangible Assets, Finite-Lived Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Total expense Total Expense Total Expense Other Deferred Tax Liabilities, Other Statement [Table] Statement [Table] Total deferred tax (benefit) provision Deferred Income Tax Expense (Benefit) Adjustments to reconcile net (loss) income to net cash provided by operating activities: Adjustments to reconcile net (loss) income to net cash provided by (used in) operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Cash Flows from Financing Activities: Cash Flows from Financing Activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Gain (loss) on sale of financial assets Gain (Loss) on Disposition of Assets for Financial Service Operations All Adjustments to Compensation All Adjustments to Compensation [Member] Net Amounts of Liabilities Presented in the Statements of Condition Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral Weighted-Average Interest Rate Reduction Contractual Interest Rate Reduction [Member] Amendment Flag Amendment Flag Share-based compensation income tax benefit recognized Share-Based Payment Arrangement, Expense, Tax Benefit Stock issued under employee stock ownership plan Stock Issued During Period, Value, Employee Stock Ownership Plan Shares approved to be issued in common stock (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized Accrued interest Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss Common Equity Tier 1 (to risk-weighted assets), Threshold to be a Well Capitalized Bank Holding Company, Amount Tier One Common Equity Required to be Well Capitalized Tier One Common Equity Required to be Well Capitalized Termination Date Trading Arrangement Termination Date Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] 2028 Time Deposit Maturities, Year Three Schedule of Collateral Dependent Loans Schedule of Collateral Dependent Loans [Table Text Block] Schedule of Collateral Dependent Loans Allowance for credit losses on loans Allowance for Credit Losses Allowance for credit loss Beginning balance Ending balance Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Subordinated notes Subordinated Debt Obligations, Fair Value Disclosure Within one year Debt Securities, Held-to-Maturity, Amortized Cost Excluding Accrued Interest, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Amortization of net unrealized loss on AFS securities transferred to HTM Amortization of net unrealized loss on AFS securities transferred to HTM Amortization Of Net Unrealized Loss On Available-For-Sale Securities Transferred To Held-To-Maturity Amortization Of Net Unrealized Loss On Available-For-Sale Securities Transferred To Held-To-Maturity Share-Based Payment Arrangement, Tranche Three Share-Based Payment Arrangement, Tranche Three [Member] Noncash director compensation expense Noncash director compensation expense Compensation Expense Common Stock For Director Fees Noncash director fees payable in common stock expensed by the entity during the period. As noncash, this element is added back to net income when calculating net cash generated by operating activities using the indirect method. Weighted average discount rate Operating Lease, Weighted Average Discount Rate, Percent Schedule of Share-based Compensation, Stock Options, Activity Share-Based Payment Arrangement, Option, Activity [Table Text Block] Credit Rating, Moody's And/Or Standard & Poor's [Axis] Credit Rating, Moody's And/Or Standard & Poor's [Axis] Credit Rating, Moody's And/Or Standard & Poor's Basic (in shares) Weighted average basic common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic New Jersey NEW JERSEY Schedule of Earnings Per Share Reconciliation Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Stock Options Exercisable (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number Minimum annual contribution per employee, percent of eligible compensation Defined Contribution Plan, Minimum Annual Contribution Per Employee, Percent Defined Contribution Plan, Minimum Annual Contribution Per Employee, Percent Exercise Price Range [Domain] Exercise Price Range [Domain] Debt Disclosure [Abstract] Debt Disclosure [Abstract] $30.01 - $40.00 Price Range Three [Member] Price Range Three [Member] Expense Costs and Expenses [Abstract] Total investment securities pledged to the State of California Pledged to State of California [Member] Pledged to the State of California [Member] Employee Stock Purchase Plan, 2017 Employee Stock Purchase Plan, 2017 [Member] Employee Stock Purchase Plan, 2007 [Member] Stock issued in payment of director fees (in shares) Stock Issued In Payment Of Director Fees Shares Common stock issued by an Entity to its directors in payment of services they render in number of shares. Change in net unrealized losses on available-for-sale securities Change in net unrealized gains or losses on available-for-sale securities OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Document Financial Statement Restatement Recovery Analysis Document Financial Statement Restatement Recovery Analysis [Flag] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Consolidated Entities [Axis] Consolidated Entities [Axis] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Unrecognized purchase discounts on non-PCI loans Certain Loans Acquired in Transfer Without Evidence of Deteriorated Credit, Unrecognized Purchase Discounts Amount of unrecognized purchase discounts from face amounts of acquired loans without evidence of credit deterioration, net of unamortized purchase premiums. A2 / A Moody's And/Or Standard & Poor's A Rating [Member] Moody's And/Or Standard & Poor's A Rating Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross Charitable contributions Charitable Contributions Expense Charitable Contributions Expense Financing Receivable Financing Receivable [Member] Use of Estimates Use of Estimates, Policy [Policy Text Block] Total Capital (to risk-weighted assets), Actual, Amount Banking Regulation, Total Capital, Actual Financial Instruments Owned and Pledged as Collateral [Table] Financial Instruments Owned and Pledged as Collateral [Table] Age ratable vesting ends Defined Benefits Plan, Age Ratable Vesting Ends Defined Benefits Plan, Age Ratable Vesting Ends Gross Amounts Offset in the Statements of Condition Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Insider Trading Arrangements [Line Items] Prior Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year Current Financial Asset, Not Past Due [Member] Available-for-sale, allowance for credit loss Allowance for Credit Losses Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Debt Securities, Held-to-maturity, Unrealized Loss Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss [Abstract] Total liabilities Liabilities 2030 Finance Lease, Liability, to be Paid, Year Five Defined contribution plan, number of years to be fully vested Defined Contribution Plan, Number of Years to be Fully Vested Defined Contribution Plan, Number of Years to be Fully Vested Percent of Portfolio Class Total Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Total Income Taxes Paid, Net, Greater Than 5% Of Total Income Taxes Paid, Net, Greater Than 5% Of Total Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] Schedule of Available-for-sale Securities and Held-to-maturity Securities [Line Items] Savings accounts Deposits, Savings Deposits Gross Amounts Not Offset in the Statements of Condition, Financial Instruments Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Auditor Information [Abstract] Auditor Information Asset-backed securities Asset-Backed Securities [Member] Consolidation Items [Axis] Consolidation Items [Axis] Schedule of Contractual Amount, Off-Balance Sheet Risks Schedule Of Contractual Amount, Off-Balance Sheet Risks [Table Text Block] Schedule Of Contractual Amount, Off-Balance Sheet Risks [Table Text Block] Interest on subordinated notes Interest Expense, Subordinated Notes and Debentures Counterparty Name [Axis] Counterparty Name [Axis] Financing Receivable Portfolio Concentration Risk Financing Receivable Class Concentration Risk [Member] Financing Receivable Class Concentration Risk Proceeds from paydowns/maturities of held-to-maturity securities Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities Held-to-maturity, at amortized cost (net of zero allowance for credit losses at December 31, 2025 and 2024) Net Carrying Amount Total Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member]