XML 118 R100.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Benefit Plans - Deferred Compensation Plan (Details) - USD ($) $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2024 | Jan. 01, 2024 | Dec. 31, 2023 | Jan. 01, 2023
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |
Interest rate earned on deferred amounts, prime rate first business day of year |  | 8.50% |  | 7.50%
Deferred compensation obligation | $ 6.0 |  | $ 6.6 |
Annual Salary | Management |  |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |
Maximum percentage of compensation allowed to be deferred | 80.00% |  |  |
Deferred Bonus | Management |  |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |
Maximum percentage of compensation allowed to be deferred | 100.00% |  |  |

X
- Definition Deferred Compensation Arrangement with Individual, Maximum Elected Deferral by Employee, Percent + References No definition available. + Details
Name: | bmrc_DeferredCompensationArrangementWithIndividualMaximumElectedDeferralByEmployeePercent
Namespace Prefix: | bmrc_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Deferred Compensation Arrangement with Individual, Deferred Interest Earned, Percent + References No definition available. + Details
Name: | bmrc_DeferredCompensationArrangementwithIndividualDeferredInterestEarnedPercent
Namespace Prefix: | bmrc_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
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 No definition available. + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The carrying amount of the liability as of the balance sheet date to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 710 -SubTopic 10 -Name Accounting Standards Codification -Section 30 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483043/710-10-30-1 + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=bmrc_AnnualSalaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=srt_ManagementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis=us-gaap_DeferredBonusMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |