XML 112 R100.htm IDEA: XBRL DOCUMENT
v3.22.4

Benefit Plans - Salary Continuation Plan (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2022 | Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items] |  |
Percentage of salary paid upon retirement | 25.00% |
Period before ratable vesting begins | 5 years |
Age ratable vesting ends | 65 years |
Liability under the Salary Continuation Plan | $ 4.7 | $ 5.3
Minimum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Payment period determined by service period | 5 years |
Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Payment period determined by service period | 15 years |

X
- Definition Defined Benefit Plan, Payment Period Determined By Service Period + References No definition available. + Details
Name: | bmrc_DefinedBenefitPlanPaymentPeriodDeterminedByServicePeriod
Namespace Prefix: | bmrc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Percentage of Salary Paid upon Retirement + References No definition available. + Details
Name: | bmrc_DefinedBenefitPlanPercentageOfSalaryPaidUponRetirement
Namespace Prefix: | bmrc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefits Plan, Age Ratable Vesting Ends + References No definition available. + Details
Name: | bmrc_DefinedBenefitsPlanAgeRatableVestingEnds
Namespace Prefix: | bmrc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefits Plan, Period Before Ratable Vesting Begins + References No definition available. + Details
Name: | bmrc_DefinedBenefitsPlanPeriodBeforeRatableVestingBegins
Namespace Prefix: | bmrc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI https://asc.fasb.org/extlink&oid=123453770&loc=d3e1703-114919 + Details
Name: | us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |