XML 38 R23.htm IDEA: XBRL DOCUMENT
v3.20.4

Financial Instruments with Off-Balance Sheet Risk | 12 Months Ended
--- | ---
Dec. 31, 2020
Fair Value Disclosures [Abstract] |
Financial Instruments with Off-Balance Sheet Risk | Financial Instruments with Off-Balance Sheet Risk We make commitments to extend credit in the normal course of business to meet the financing needs of our customers. These financial instruments include commitments to extend credit in the form of loans or through standby letters of credit. Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Because various commitments will expire without being fully drawn, the total commitment amount does not necessarily represent future cash requirements. Our credit loss exposure is equal to the contractual amount of the commitment in the event of nonperformance by the borrower. We use the same credit underwriting criteria for all credit exposure. The amount of collateral obtained, if deemed necessary by us, is based on management's credit evaluation of the borrower. Collateral types pledged may include accounts receivable, inventory, other personal property and real property. 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, 2020 | December 31, 2019
Commercial lines of credit | $ | 297,898 |  | $ | 287,533 |
Revolving home equity lines | 191,969 |  | 189,035 |
Undisbursed construction loans | 101,307 |  | 41,033 |
Personal and other lines of credit | 10,611 |  | 9,567 |
Standby letters of credit | 2,657 |  | 1,964 |
Total unfunded loan commitments and standby letters of credit | $ | 604,442 |  | $ | 529,132 |
As of December 31, 2020, approximately 35% of the commitments expire in 2021, 54% expire between 2022 and 2028 and 11% expire thereafter. We adopted the CECL accounting standard on December 31, 2020, which was previously postponed under the optional accounting relief provisions of the CARES Act (refer to Note 1, Summary of Significant Accounting Policies and Note 3, Loans and Allowance for Credit Losses for additional information). During the first nine months of 2020, we increased the allowance for credit losses on unfunded loan commitments under the incurred loss method ("previous GAAP") by $610 thousand. Upon adoption of the CECL standard, we increased the allowance for unfunded loan commitments by $1.1 million, which represented the difference between the allowance calculated under the CECL method as of December 31, 2020 and the incurred loss method as of September 30, 2020. The $1.1 million increase in the allowance for unfunded loan commitments included approximately $550 thousand related to a $36.9 million increase in available commitments during the fourth quarter of 2020. The remaining increase was due to changes in credit loss assumptions between the CECL and incurred loss methods. The prior period allowance is reported in accordance with previous GAAP and was $1.1 million as of December 31, 2019.

X
- Definition Financial Instruments with Off-Balance Sheet Risk [Text Block] + References No definition available. + Details
Name: | bmrc_FinancialInstrumentsWithOffBalanceSheetRiskTextBlock
Namespace Prefix: | bmrc_
Data Type: | nonnum: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