XML 61 R48.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Loans and Allowance for Loan Losses - Percentage of Loans Geographically and by Collateral (Details) | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Commercial real estate loans |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Percentage of loans by class to all loans | 65.00% |
Commercial real estate loans | California |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Percentage of loans by class and geographic location | 83.00% |
Loans secured by real estate |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Percentage of loans by class to all loans | 85.00% | 85.00%

X
- Definition Loans and Leases Receivable, Ratio of Class of Loans by Geographic Location of Property + References No definition available. + Details
Name: | bmrc_LoansAndLeasesReceivableRatioOfClassOfLoansByGeographicLocationOfProperty
Namespace Prefix: | bmrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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: | num: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_AccountsNotesAndLoansReceivableLineItems
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_StatementGeographicalAxis=stpr_CA
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: |