XML 54 R44.htm IDEA: XBRL DOCUMENT
v3.19.1

Note 3 - Loans and Allowance for Loan Losses - Retail Credit Exposure (Details) - USD ($) | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Loans | $ 2,799,639,000 | $ 2,753,085,000
Retail Portfolio Segment [Member] |  |
Loans | 399,441,000 | 392,979,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member] |  |
Loans | 83,127,000 | 85,439,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] |  |
Loans | 316,314,000 | 307,540,000
Originated Loan [Member] |  |
Loans | 2,511,036,000 | 2,452,446,000
Originated Loan [Member] | Retail Portfolio Segment [Member] |  |
Loans | 312,323,000 | 300,448,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member] |  |
Loans | 64,769,000 | 65,023,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] |  |
Loans | 247,554,000 | 235,425,000
Acquired Loan [Member] |  |
Loans | 288,603,000 | 300,639,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] |  |
Loans | 87,118,000 | 92,531,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member] |  |
Loans | 18,358,000 | 20,416,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] |  |
Loans | $ 68,760,000 | $ 72,115,000

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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524 + Details
Name: | us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbwm_HomeEquityAndOtherMember
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_FinancialInstrumentAxis=mbwm_OriginatedLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=mbwm_AcquiredLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |