XML 47 R37.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Loans and Allowance for Loan Losses - Outstanding and Aging Analysis (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 USD ($) loan | Dec. 31, 2017 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | $ 389,000 | $ 2,331,000
Current | 1,671,351,000 | 1,676,682,000
Total loans | 1,671,740,000 | 1,679,013,000
Non-accrual | $ 392,000 | $ 406,000
Number of purchase credit impaired (PCI) loans with unpaid balances | loan | 1 | 3
Unpaid balances on purchase credit impaired (PCI) loans | $ 11,000 | $ 131,000
Purchased Credit Impaired (PCI) loans no longer accreting interest | 0 | 0
Purchased Credit-impaired (PCI) loans accreting interest | 2,100,000 |
Loans past due more than 90 days still accruing | 0 | 0
Deferred loan fees | 928,000 | 818,000
Unaccreted purchase discounts on non-PCI loans | 1,100,000 | 1,200,000
30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 385,000 | 684,000
60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 4,000 | 1,340,000
90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 307,000
Commercial loans | Commercial and industrial |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 4,000 | 1,340,000
Current | 231,676,000 | 234,495,000
Total loans | 231,680,000 | 235,835,000
Non-accrual | 0 | 0
Commercial loans | Commercial and industrial | 30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial loans | Commercial and industrial | 60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 4,000 | 1,340,000
Commercial loans | Commercial and industrial | 90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Commercial real estate, owner-occupied |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Current | 300,377,000 | 300,963,000
Total loans | 300,377,000 | 300,963,000
Non-accrual | 0 | 0
Commercial real estate loans | Commercial real estate, owner-occupied | 30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Commercial real estate, owner-occupied | 60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Commercial real estate, owner-occupied | 90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Commercial real estate, investor |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Current | 828,945,000 | 822,984,000
Total loans | 828,945,000 | 822,984,000
Non-accrual | 0 | 0
Commercial real estate loans | Commercial real estate, investor | 30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Commercial real estate, investor | 60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Commercial real estate, investor | 90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Construction |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Current | 64,978,000 | 63,828,000
Total loans | 64,978,000 | 63,828,000
Non-accrual | 0 | 0
Commercial real estate loans | Construction | 30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Construction | 60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Commercial real estate loans | Construction | 90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Residential loans | Home equity |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 385,000 | 406,000
Current | 124,314,000 | 132,061,000
Total loans | 124,699,000 | 132,467,000
Non-accrual | 392,000 | 406,000
Residential loans | Home equity | 30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 385,000 | 99,000
Residential loans | Home equity | 60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Residential loans | Home equity | 90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 307,000
Residential loans | Other residential |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 255,000
Current | 95,621,000 | 95,271,000
Total loans | 95,621,000 | 95,526,000
Non-accrual | 0 | 0
Residential loans | Other residential | 30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 255,000
Residential loans | Other residential | 60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Residential loans | Other residential | 90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Consumer loans | Installment and other consumer |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 330,000
Current | 25,440,000 | 27,080,000
Total loans | 25,440,000 | 27,410,000
Non-accrual | 0 | 0
Consumer loans | Installment and other consumer | 30-59 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 330,000
Consumer loans | Installment and other consumer | 60-89 days past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | 0 | 0
Consumer loans | Installment and other consumer | 90 days or more past due |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans past due | $ 0 | $ 0

X
- Definition The carrying balance of certain loans acquired with evidence of deteriorated credit quality and currently accreting interests. + References No definition available. + Details
Name: | bmrc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalanceAccrualStatus
Namespace Prefix: | bmrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The carrying balance of certain Loans acquired in transfer with deteriorated credit quality not accounted for as debt securities, and currently not accreting interests (nonaccrual status). + References No definition available. + Details
Name: | bmrc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesOutstandingBalanceNonaccrualStatus
Namespace Prefix: | bmrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Number Of Loans With Unpaid Balances + References No definition available. + Details
Name: | bmrc_CertainLoansAcquiredinTransferNotAccountedforasDebtSecuritiesNumberOfLoansWithUnpaidBalances
Namespace Prefix: | bmrc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of unaccreted purchase discounts from face amounts of acquired loans without evidence of credit deterioration, net of unamortized purchase premiums. + References No definition available. + Details
Name: | bmrc_CertainLoansAcquiredinTransferWithoutEvidenceofDeterioratedCreditUnaccretedPurchaseDiscounts
Namespace Prefix: | bmrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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
- Definition The undiscounted sum of all amounts, including amounts deemed principal, interest, fees, penalties, and other under the loan, owed to the investor at the reporting date, whether or not currently due and whether or not any such amounts have been written or charged off by the investor. This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 15 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82894507&loc=d3e13503-111538 + Details
Name: | us-gaap_CertainLoansAcquiredInTransferAccountedForAsDebtSecuritiesOutstandingBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Recorded investment in financing receivables that are 90 days or more past due and still accruing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing receivables that are current. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Recorded Investment in financing receivables that are past due at the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentPastDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=84159169&loc=d3e10152-111534 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=84165051&loc=d3e45377-112738 + Details
Name: | us-gaap_LoansAndLeasesReceivableDeferredIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524 + Details
Name: | us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_CommercialRealEstateLoanOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_CommercialRealEstateLoanInvestorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_OtherResidentialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bmrc_InstallmentAndOtherConsumerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |