XML 125 R112.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Derivative Financial Instruments and Hedging Activities - Schedule of Interest Income (Details) - Fair value hedge - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Interest on investment securities |  |  |
Derivatives, Fair Value [Line Items] |  |  |
(Decrease) increase in fair value of interest rate swaps hedging loans receivable | $ (1,359) | $ 0 | $ 0
Hedged interest earned (paid) | 367 | 0 | 0
Increase (decrease) in carrying value included in the hedged loans | 1,359 | 0 | 0
Net gain (loss) recognized in interest income on loans | 367 | 0 | 0
Interest and fees on loans |  |  |
Derivatives, Fair Value [Line Items] |  |  |
(Decrease) increase in fair value of interest rate swaps hedging loans receivable | (317) | 1,687 | 827
Hedged interest earned (paid) | 268 | (143) | (369)
Increase (decrease) in carrying value included in the hedged loans | 359 | (1,666) | (814)
Decrease in value of yield maintenance agreement | (9) | (10) | (11)
Net gain (loss) recognized in interest income on loans | $ 301 | $ (132) | $ (367)

X
- Definition Payment on interest rate swaps recorded in interest income. + References No definition available. + Details
Name: | bmrc_DerivativeHedgedInterestEarnedPaid
Namespace Prefix: | bmrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Increase (Decrease) in value of yield maintenance agreement recognized against interest income. + References No definition available. + Details
Name: | bmrc_DerivativeIncreaseDecreaseInValueOfYieldMaintenanceAgreement
Namespace Prefix: | bmrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4A -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4A + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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_DerivativesFairValueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unrealized gain (loss) included in earnings related to the fair value of the hedged item in an interest rate fair value hedge, offset by the gain (loss) on the hedging instrument to the extent that the fair value hedge is determined to be effective. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4A Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4C + Details
Name: | us-gaap_IncreaseDecreaseInFairValueOfHedgedItemInInterestRateFairValueHedge1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of unrealized gain (loss) related to the fair value of interest rate derivatives designated as fair value hedging instruments, as offset by the gain (loss) on the hedged item to the extent that the fair value hedge is determined to be effective. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4A Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-4C + Details
Name: | us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=bmrc_InterestOnInvestmentSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=bmrc_InterestAndFeesOnLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |