Benefit Plans	12 Months Ended
Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Benefit Plans	Benefit Plans In 2003, we established a Deferred Compensation Plan that allows certain key Management personnel designated by the Board of Directors of the Bank to defer up to 80% of their salary and 100% of their annual bonus. The plan was amended in 2007 in order to comply with the most recent Internal Revenue Code Section 409A changes. Under the amended plan, amounts deferred earn interest that is equal to the prime rate as published in the Wall Street Journal, on the first business day of the year, which was 3.5% on January 1, 2016, and 3.25% on both January 1, 2015 and 2014. Our deferred compensation obligation totaled $3.2 million and $3.0 million at December 31, 2016 and 2015, respectively, and is included in interest payable and other liabilities. Our 401(k) Defined Contribution Plan (the “401(k) Plan”) commenced in May 1990 and is available to all regular employees at least eighteen years of age who complete ninety days of service, and enter the plan during one of the four open enrollment dates (January 1, April 1, July 1, and October 1) of each year. Under the 401(k) Plan, employees can defer between 1% and 50% of their eligible compensation, up to the maximum amount allowed by the Internal Revenue Code. Contributions to the 401(k) Plan for the employer match are vested at a rate of 20% per year over a five year period. The Bank matched 50% of each participant's contribution prior to 2013 at which time the Bank increased the match to 60%, with a maximum of $4 thousand annually. Employer contributions totaled $589 thousand, $555 thousand and $548 thousand for the years ended December 31, 2016, 2015 and 2014, respectively. In 1999, the 401(k) Plan was amended to include an employee stock ownership component and was renamed the Bank of Marin Employee Stock Ownership and Savings Plan (the “Plan”). Under the terms of the Plan, as amended, the Board of Directors determines a specific portion of the Bank's profits to be contributed to the employee stock ownership each year either in common stock or in cash for the purchase of Bancorp stock to be allocated to all eligible employees based on a percentage of their salaries, regardless of whether an employee is participating in the 401(k) plan or not. In January 2010, the Bank of Marin Employee Stock Ownership and Savings Plan was split into two plans: Bank of Marin 401(k) Plan and Bank of Marin Employee Stock Ownership Plan ("ESOP"). The same eligibility criteria apply under the ESOP, while employees' contributions are not permitted. For all participants, employer contributions vest over a five year period of service. After five years of service, all employer contributions vest immediately. The Bank of Marin 401(k) Plan was amended in early 2016 to incorporate recent changes in the pension laws, and was amended again in November 2016 to include a Roth 401(k) option. The Bank contributed cash in the amount of $1.2 million, $1.1 million and $1.2 million in 2016, 2015 and 2014, respectively, to the ESOP, which purchased Bancorp stock at market prices. Cash dividends paid on Bancorp stock held by the ESOP are used to purchase additional shares in the open market. All shares of Bancorp stock held by the ESOP are included in the calculations of basic and diluted earnings per share. The employer contributions to the ESOP and the 401(k) Plan are included in salaries and benefits expense. On January 1, 2011, we established a Salary Continuation Plan for a select group of Executive Management, who will receive twenty-five percent of their estimated salary at retirement as salary continuation benefit payments upon retirement. Each participant will need to participate in this plan for five years before vesting begins. After five years, the participant will vest ratably in the benefit over the remaining period until age 65. This Plan is unfunded and nonqualified for tax purposes and for purposes of Title I of the Employee Retirement Income Security Act of 1974. At December 31, 2016 and 2015, respectively, our liability under the Salary Continuation Plan was $1.0 million and $823 thousand recorded in interest payable and other liabilities.

Benefit Plans

In 2003, we established a Deferred Compensation Plan that allows certain key Management personnel designated by the Board of Directors of the Bank to defer up to 80% of their salary and 100% of their annual bonus. The plan was amended in 2007 in order to comply with the most recent Internal Revenue Code Section 409A changes. Under the amended plan, amounts deferred earn interest that is equal to the prime rate as published in the Wall Street Journal, on the first business day of the year, which was 3.5% on January 1, 2016, and 3.25% on both January 1, 2015 and 2014. Our deferred compensation obligation totaled $3.2 million and $3.0 million at December 31, 2016 and 2015, respectively, and is included in interest payable and other liabilities.

Our 401(k) Defined Contribution Plan (the “401(k) Plan”) commenced in May 1990 and is available to all regular employees at least eighteen years of age who complete ninety days of service, and enter the plan during one of the four open enrollment dates (January 1, April 1, July 1, and October 1) of each year. Under the 401(k) Plan, employees can defer between 1% and 50% of their eligible compensation, up to the maximum amount allowed by the Internal Revenue Code. Contributions to the 401(k) Plan for the employer match are vested at a rate of 20% per year over a five year period. The Bank matched 50% of each participant's contribution prior to 2013 at which time the Bank increased the match to 60%, with a maximum of $4 thousand annually. Employer contributions totaled $589 thousand, $555 thousand and $548 thousand for the years ended December 31, 2016, 2015 and 2014, respectively.

In 1999, the 401(k) Plan was amended to include an employee stock ownership component and was renamed the Bank of Marin Employee Stock Ownership and Savings Plan (the “Plan”). Under the terms of the Plan, as amended, the Board of Directors determines a specific portion of the Bank's profits to be contributed to the employee stock ownership each year either in common stock or in cash for the purchase of Bancorp stock to be allocated to all eligible employees based on a percentage of their salaries, regardless of whether an employee is participating in the 401(k) plan or not. In January 2010, the Bank of Marin Employee Stock Ownership and Savings Plan was split into two plans: Bank of Marin 401(k) Plan and Bank of Marin Employee Stock Ownership Plan ("ESOP"). The same eligibility criteria apply under the ESOP, while employees' contributions are not permitted. For all participants, employer contributions vest over a five year period of service. After five years of service, all employer contributions vest immediately. The Bank of Marin 401(k) Plan was amended in early 2016 to incorporate recent changes in the pension laws, and was amended again in November 2016 to include a Roth 401(k) option.

The Bank contributed cash in the amount of $1.2 million, $1.1 million and $1.2 million in 2016, 2015 and 2014, respectively, to the ESOP, which purchased Bancorp stock at market prices. Cash dividends paid on Bancorp stock held by the ESOP are used to purchase additional shares in the open market. All shares of Bancorp stock held by the ESOP are included in the calculations of basic and diluted earnings per share. The employer contributions to the ESOP and the 401(k) Plan are included in salaries and benefits expense.

On January 1, 2011, we established a Salary Continuation Plan for a select group of Executive Management, who will receive twenty-five percent of their estimated salary at retirement as salary continuation benefit payments upon retirement. Each participant will need to participate in this plan for five years before vesting begins. After five years, the participant will vest ratably in the benefit over the remaining period until age 65. This Plan is unfunded and nonqualified for tax purposes and for purposes of Title I of the Employee Retirement Income Security Act of 1974. At December 31, 2016 and 2015, respectively, our liability under the Salary Continuation Plan was $1.0 million and $823 thousand recorded in interest payable and other liabilities.