XML 28 R1.htm IDEA: XBRL DOCUMENT v3.20.1
Cover - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2019
Feb. 28, 2020
Jun. 29, 2019
Cover page.      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
Document Transition Report false    
Entity File Number 001-33572    
Entity Registrant Name Bank of Marin Bancorp    
Entity Incorporation, State or Country Code CA    
Entity Tax Identification Number 20-8859754    
Entity Address, Address Line One 504 Redwood Blvd.    
Entity Address, Address Line Two  Suite 100    
Entity Address, City or Town Novato    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 94947    
City Area Code 415    
Local Phone Number 763-4520    
Title of 12(g) Security    Common Stock, No Par Value,    
Trading Symbol BMRC    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Accelerated Filer    
Smaller Reporting Company true    
Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 525
Entity Common Stock, Shares Outstanding (in shares)   13,596,535  
Documents Incorporated by Reference
Portions of the registrant's Proxy Statement for the Annual Meeting of Shareholders to be held on May 12, 2020 are incorporated by reference into Part III.
    
Entity Central Index Key 0001403475    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Amendment Flag false    
Current Fiscal Year End Date --12-31