XML 84 R66.htm IDEA: XBRL DOCUMENT v3.25.0.1

Loans and Allowance for Credit Losses on Loans - Concentrations of Credit Narrative (Details)	Dec. 31, 2024	Dec. 31, 2023
Commercial real estate loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Percentage of loans by class to all loans	77.00%	75.00%
Loans secured by real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Percentage of loans by class to all loans	89.00%	90.00%

X

- Definition

Loans and Leases Receivable, Ratio of Class to All Loans

+ References

No definition available.

+ Details

Name:	bmrc_LoansAndLeasesReceivableRatioOfClassToAllLoans
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph c
-Publisher SEC

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: