XML 31 R28.htm IDEA: XBRL DOCUMENT
v3.3.0.814

Note 8 - Commitments and Off-balance Sheet Risk (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2015
Disclosure Text Block Supplement [Abstract] |
Summary of Contractual Amounts of Financial Instruments with Off-balance Sheet Risk [Table Text Block] |
|  | September 30, |  |  | December 31, |
|  | 2015 |  |  | 2014 |
Commercial unused lines of credit |  | $ | 488,744,000 |  |  | $ | 554,856,000 |
Unused lines of credit secured by 1 – 4 family residential properties |  |  | 61,534,000 |  |  |  | 60,983,000 |
Credit card unused lines of credit |  |  | 14,100,000 |  |  |  | 11,649,000 |
Other consumer unused lines of credit |  |  | 9,265,000 |  |  |  | 8,673,000 |
Commitments to make loans |  |  | 238,884,000 |  |  |  | 110,126,000 |
Standby letters of credit |  |  | 35,562,000 |  |  |  | 35,461,000 |
|  | $ | 848,089,000 |  |  | $ | 781,748,000 |

X
- Definition Tabular disclosure of contractual amounts of financial instruments with off-balance sheet risk. + References No definition available. + Details
Name: | mbwm_SummaryOfContractualAmountsOfFinancialInstrumentsWithOffBalanceSheetRiskTableTextBlock
Namespace Prefix: | mbwm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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