Benefit Plans	12 Months Ended
Dec. 31, 2011
Benefit Plans [Abstract]
Benefit Plans	Note 11: Benefit Plans In 2003, we established a Deferred Compensation Plan that allows key executive officers 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 on the first business of day of year, which remained unchanged at 3.25% for the past three years. Our deferred compensation obligation of $2.7 million and $2.8 million at December 31, 2011 and 2010, respectively, 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 this plan employees can defer between 1% and 50% of their eligible compensation, up to the maximum amount allowed by the Internal Revenue Code. The Bank will match 50% of each participant's contribution up to $4 thousand annually. Employer contributions totaled $366 thousand, $277 thousand and $311 thousand for the years ended December 31, 2011, 2010 and 2009, 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 ESOP 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 set percentage of their salaries, regardless of whether an employee is participating in the 401(k) plan or not. For the years ended December 31, 2011, 2010 and 2009, the Bank contributed $1.1 million, $898 thousand and $750 thousand, respectively, to the ESOP by purchasing Bancorp stock in the open market and by buying stock back from employees or other private parties who are diversifying their portfolio or taking distributions. Contributions to the Plan for both the 401(k) employer matching contribution and for the ESOP are included in salaries and benefits expenses and vested at a rate of 20% per year over a five-year period. As of December 31, 2011, cash dividends on Bancorp's stock held by the Plan are used to purchase additional shares in the open market. All shares of the Bancorp's stock held by the Plan are included in the calculations of basic and diluted earnings per share. In January 2010, the Plan was bifurcated into a separate 401(k) Plan and a separate ESOP Plan. The same eligibility criteria and employer contribution allocation apply under the ESOP Plan, while employees' contributions are not permitted. For participants who join the ESOP on or after January 1, 2010, employer contributions vest 0% in year one, 20% in years two through four and 40% in year five. On January 1, 2011, we established a Salary Continuation Plan to a select group of executive management, who will receive twenty-five percent of their 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 ratable 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. Our liability under the Salary Continuation Plan was $114 thousand recorded in interest payable and other liabilities at December 31, 2011.

Note 11: Benefit Plans

In 2003, we established a Deferred Compensation Plan that allows key executive officers 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 on the first business of day of year, which remained unchanged at 3.25% for the past three years. Our deferred compensation obligation of $2.7 million and $2.8 million at December 31, 2011 and 2010, respectively, 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 this plan employees can defer between 1% and 50% of their eligible compensation, up to the maximum amount allowed by the Internal Revenue Code. The Bank will match 50% of each participant's contribution up to $4 thousand annually. Employer contributions totaled $366 thousand, $277 thousand and $311 thousand for the years ended December 31, 2011, 2010 and 2009, 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 ESOP 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 set percentage of their salaries, regardless of whether an employee is participating in the 401(k) plan or not. For the years ended December 31, 2011, 2010 and 2009, the Bank contributed $1.1 million, $898 thousand and $750 thousand, respectively, to the ESOP by purchasing Bancorp stock in the open market and by buying stock back from employees or other private parties who are diversifying their portfolio or taking distributions. Contributions to the Plan for both the 401(k) employer matching contribution and for the ESOP are included in salaries and benefits expenses and vested at a rate of 20% per year over a five-year period. As of December 31, 2011, cash dividends on Bancorp's stock held by the Plan are used to purchase additional shares in the open market. All shares of the Bancorp's stock held by the Plan are included in the calculations of basic and diluted earnings per share.

In January 2010, the Plan was bifurcated into a separate 401(k) Plan and a separate ESOP Plan. The same eligibility criteria and employer contribution allocation apply under the ESOP Plan, while employees' contributions are not permitted. For participants who join the ESOP on or after January 1, 2010, employer contributions vest 0% in year one, 20% in years two through four and 40% in year five.

On January 1, 2011, we established a Salary Continuation Plan to a select group of executive management, who will receive twenty-five percent of their 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 ratable 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. Our liability under the Salary Continuation Plan was $114 thousand recorded in interest payable and other liabilities at December 31, 2011.