XML 28 R48.htm IDEA: XBRL DOCUMENT v2.4.0.8

Loans and Allowance for Loan Losses (Details Textual) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Loans and Allowance for Loan Losses (Textual) [Abstract]
Total loans	$ 1,058,662,000	$ 1,060,996,000	$ 1,058,662,000	$ 1,060,996,000	$ 1,041,189,000
Amount of increase in total loans			17,500,000
Percentage increase in total loans			1.70%
Interest income recognized on impaired loans	$ 700,000	$ 400,000	$ 1,300,000	$ 800,000
Number of past due days for loans modified as TDR	30 days	30 days	30 days	30 days

X

- Details

Name:	mbwm_LoansAndAllowanceForLoanLossesTextualAbstract
Namespace Prefix:	mbwm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Loans and leases receivable percentage period increase decrease.

+ References

No definition available.

+ Details

Name:	mbwm_LoansAndLeasesReceivablePercentagePeriodIncreaseDecrease
Namespace Prefix:	mbwm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Loans and leases receivable period increase decrease.

+ References

No definition available.

+ Details

Name:	mbwm_LoansAndLeasesReceivablePeriodIncreaseDecrease
Namespace Prefix:	mbwm_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of past due days for loans modified as TDR.

+ References

No definition available.

+ Details

Name:	mbwm_NumberOfPastDueDaysForLoansModifiedAsTroubledDebtRestructuring
Namespace Prefix:	mbwm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5212-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5074-111524



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant