XML 51 R42.htm IDEA: XBRL DOCUMENT v3.23.2

Note 3 - Loans and Allowance for Credit Losses - Components of Loan Portfolio (Details) - USD ($)		6 Months Ended
		Jun. 30, 2023	Dec. 31, 2022
Loans		$ 4,051,843,000	$ 3,916,619,000
Percent of portfolio		100.00%	100.00%
Period increase (decrease)		3.50%
Commercial Portfolio Segment [Member]
Loans		$ 3,188,585,000	$ 3,131,830,000
Percent of portfolio		78.70%	80.00%
Period increase (decrease)		1.80%
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans		$ 1,212,196,000	$ 1,185,083,000
Percent of portfolio		29.90%	30.30%
Period increase (decrease)		2.30%
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Loans		$ 72,682,000	$ 61,873,000
Percent of portfolio		1.80%	1.60%
Period increase (decrease)		17.50%
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Loans		$ 659,201,000	$ 639,192,000
Percent of portfolio		16.30%	16.30%
Period increase (decrease)		3.10%
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Loans	[1]	$ 957,221,000	$ 979,214,000
Percent of portfolio		23.60%	25.00%
Period increase (decrease)		(2.20%)
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Loans	[1]	$ 287,285,000	$ 266,468,000
Percent of portfolio		7.10%	6.80%
Period increase (decrease)		7.80%
Retail Portfolio Segment [Member]
Loans		$ 863,258,000	$ 784,789,000
Percent of portfolio		21.30%	20.00%
Period increase (decrease)		10.00%
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Loans		$ 833,198,000	$ 755,036,000
Percent of portfolio		20.60%	19.30%
Period increase (decrease)		10.40%
Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans		$ 30,060,000	$ 29,753,000
Percent of portfolio		0.70%	0.70%
Period increase (decrease)		1.00%
[1] We have made certain reclassifications of how multi-family construction loans are disaggregated by loan segment. The table above reflects an increase of $54.5 million in Real Estate – Multi-Family and Residential Rental loans and a corresponding decrease in Real Estate – Non-Owner Occupied loans as of December 31, 2022. All the tables that follow have been adjusted to reflect the reclassifications as of the applicable dates.

X

- Definition

Loan portfolio classes and segments expressed as a percentage of the companies aggregate loans.

+ References

No definition available.

+ Details

Name:	mbwm_LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan
Namespace Prefix:	mbwm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The percentage of increase or (decrease) during the period in loans and leases receivable net of deferred income.

+ References

No definition available.

+ Details

Name:	mbwm_LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage
Namespace Prefix:	mbwm_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479294/326-20-55-80

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479294/326-20-55-79

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (1)
-Publisher SEC

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (2)
-Publisher SEC

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Regulation S-K (SK)
-Number 229
-Section 1404
-Paragraph (a)
-Publisher SEC

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-14

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-7A

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-5

+ Details

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

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_CommercialAndIndustrialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_VacantLandAndLandDevelopmentAndResidentialConstructionLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_RealEstateOwnerOccupiedLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_RealEstateNonOwnerOccupiedLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_RealEstateMultiFamilyAndResidentialRentalLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=mbwm_RetailPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_OneToFourFamilyMortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_OtherConsumerLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: