XML 117 R52.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Deposits (Details Textual) (USD $) | 6 Months Ended |
--- | --- | ---
Jun. 30, 2013 | Dec. 31, 2012
Deposits (Textual) [Abstract] |  |
Total deposits | $ 1,061,315,000 | $ 1,135,204,000
Amount of decrease in total deposits | $ 73,900,000 |
Percentage of decrease in total deposits | 6.50% |

X
- Definition Change in deposit liabilities. + References No definition available. + Details
Name: | mbwm_ChangeInDepositLiabilities
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | mbwm_DepositsTextualAbstract
Namespace Prefix: | mbwm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of decrease in aggregate deposits. + References No definition available. + Details
Name: | mbwm_PercentageOfDecreaseInAggregateDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 9 + Details
Name: | us-gaap_Deposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant