XML 73 R33.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Note 1 - Summary of Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2019
Notes Tables |
Mortgage Loans Held for Sale [Table Text Block] |
|  | 2019 |  |  | 2018 |
Mortgage loans held for sale |  | $ | 4,978,000 |  |  | $ | 1,122,000 |
Less: Allowance to adjust to lower of cost or market |  |  | 0 |  |  |  | 0 |
Mortgage loans held for sale, net |  | $ | 4,978,000 |  |  | $ | 1,122,000 |

X
- Definition Tabular disclosure of year-end mortgage loans held for sale. + References No definition available. + Details
Name: | mbwm_MortgageLoansHeldForSaleTableTextBlock
Namespace Prefix: | mbwm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_TableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration