XML 58 R48.htm IDEA: XBRL DOCUMENT
v3.25.1

Loans and Allowance for Credit Losses on Loans - Schedule of Allocation of the Allowance for Credit Losses on Loans (Details) - USD ($) $ in Thousands | Mar. 31, 2025 | Dec. 31, 2024 | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | --- | --- | ---
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | $ 29,906 | $ 30,656 | $ 25,501 | $ 25,172
Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 11,910 | 12,051 |  |
Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 10,417 | 10,512 |  |
Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 7,579 | 8,093 |  |
Commercial and industrial | Commercial and industrial |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 1,508 | 1,576 | 1,727 | 1,712
Commercial and industrial | Commercial and industrial | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 792 | 759 |  |
Commercial and industrial | Commercial and industrial | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 615 | 672 |  |
Commercial and industrial | Commercial and industrial | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 101 | 145 |  |
Commercial real estate loans | Commercial owner-occupied |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 2,319 | 2,361 | 2,500 | 2,476
Commercial real estate loans | Commercial owner-occupied | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 1,198 | 1,241 |  |
Commercial real estate loans | Commercial owner-occupied | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 1,121 | 1,120 |  |
Commercial real estate loans | Commercial owner-occupied | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 0 | 0 |  |
Commercial real estate loans | Commercial non-owner occupied |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 21,761 | 22,093 | 15,704 | 14,933
Commercial real estate loans | Commercial non-owner occupied | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 7,549 | 7,632 |  |
Commercial real estate loans | Commercial non-owner occupied | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 6,734 | 6,528 |  |
Commercial real estate loans | Commercial non-owner occupied | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 7,478 | 7,933 |  |
Commercial real estate loans | Construction |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 416 | 638 | 1,282 | 1,832
Commercial real estate loans | Construction | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 42 | 41 |  |
Commercial real estate loans | Construction | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 374 | 597 |  |
Commercial real estate loans | Construction | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 0 | 0 |  |
Home Equity | Home equity |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 698 | 684 | 627 | 552
Home Equity | Home equity | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 636 | 620 |  |
Home Equity | Home equity | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 62 | 64 |  |
Home Equity | Home equity | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 0 | 0 |  |
Home Equity | Other residential |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 1,074 | 1,141 | 692 | 653
Home Equity | Other residential | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 1,072 | 1,133 |  |
Home Equity | Other residential | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 2 | 8 |  |
Home Equity | Other residential | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 0 | 0 |  |
Installment and other consumer loans | Installment and other consumer loans |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 884 | 908 | 920 | 976
Installment and other consumer loans | Installment and other consumer loans | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 621 | 625 |  |
Installment and other consumer loans | Installment and other consumer loans | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 263 | 268 |  |
Installment and other consumer loans | Installment and other consumer loans | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 0 | 15 |  |
Unallocated |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 1,246 | 1,255 | $ 2,049 | $ 2,038
Unallocated | Modeled expected credit losses |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 0 | 0 |  |
Unallocated | Qualitative adjustments |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | 1,246 | 1,255 |  |
Unallocated | Specific allocations |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Allowance for credit losses | $ 0 | $ 0 |  |

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 34 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-34 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 33 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-33 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 12A -Publisher FASB -URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-42 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-42 + Details
Name: | us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | bmrc_AllowanceForCreditLossAllocationAxis=bmrc_ModeledExpectedCreditLossesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | bmrc_AllowanceForCreditLossAllocationAxis=bmrc_QualitativeAdjustmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | bmrc_AllowanceForCreditLossAllocationAxis=bmrc_SpecificAllocationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_CommercialRealEstateLoanOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_CommercialRealEstateLoanNonOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_OtherResidentialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_InstallmentAndOtherConsumerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_UnallocatedFinancingReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |