XML 52 R40.htm IDEA: XBRL DOCUMENT
v3.22.4

Financial Instruments with Off-Balance Sheet Risk (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2022
Fair Value Disclosures [Abstract] |
Schedule of Contractual Amount, Off-Balance Sheet Risks | The contractual amount of unfunded loan commitments and standby letters of credit not reflected in the consolidated statements of condition are as follows:
(in thousands) | December 31, 2022 | December 31, 2021
Commercial lines of credit | $ | 292,204 |  | $ | 330,234 |
Revolving home equity lines | 218,907 |  | 210,938 |
Undisbursed construction loans | 43,179 |  | 78,381 |
Personal and other lines of credit | 10,842 |  | 11,001 |
Standby letters of credit | 1,738 |  | 3,657 |
Total unfunded loan commitments and standby letters of credit | $ | 566,870 |  | $ | 634,211 |

X
- Definition Schedule Of Contractual Amount, Off-Balance Sheet Risks [Table Text Block] + References No definition available. + Details
Name: | bmrc_ScheduleOfContractualAmountOffBalanceSheetRisksTableTextBlock
Namespace Prefix: | bmrc_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration