$MBWM
Mercantile Bank Corp Stock $mbwm

$mbwm Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-Q Financial Statement

#000143774920022892 Filed on November 06, 2020

Income Statement

Concept	2020 Q4	2020 Q3	2019 Q3
Revenue	$37.62M	$35.59M	$40.32M
YoY Change	-4.91%	-11.71%	13.61%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$3.170M	$1.300M	$900.0K
YoY Change	24.31%	44.44%	0.0%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense		$6.085M	$8.711M
YoY Change		-30.15%	54.29%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$17.74M	$13.19M	$15.55M
YoY Change	11.92%	-15.18%	24.45%
Income Tax	$3.660M	$2.507M	$2.954M
% Of Pretax Income	20.63%	19.0%	18.99%
Net Earnings	$14.08M	$10.69M	$12.60M
YoY Change	5.74%	-15.19%	24.47%
Net Earnings / Revenue	37.43%	30.02%	31.25%
Basic Earnings Per Share	$0.86	$0.66	$0.77
Diluted Earnings Per Share	$0.86	$0.66	$0.77
COMMON SHARES
Basic Shares Outstanding	16.23M	16.23M	16.39M
Diluted Shares Outstanding		16.23M	16.39M

Balance Sheet

Concept	2020 Q4	2020 Q3	2019 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$626.0M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$58.96M	$60.45M	$54.59M
YoY Change	2.85%	10.74%	13.47%
Goodwill	$49.47M	$49.47M	$49.47M
YoY Change	0.0%	0.0%	0.0%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets
YoY Change
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$4.437B	$4.421B	$3.710B
YoY Change	22.14%	19.14%	12.43%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$24.30M	$18.30M	$21.40M
YoY Change	8.48%	-14.49%	59.7%
Accrued Expenses
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$118.4M	$157.0M	$104.0M
YoY Change	15.29%	50.96%	-7.47%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$24.30M	$18.30M	$21.40M
YoY Change	8.48%	-14.49%	59.7%
LONG-TERM LIABILITIES
Long-Term Debt	$47.60M	$47.40M	$46.70M
YoY Change	1.49%	1.5%	1.52%
Other Long-Term Liabilities
YoY Change
Total Long-Term Liabilities	$47.60M	$47.40M	$46.70M
YoY Change	1.49%	1.5%	1.52%
TOTAL LIABILITIES
Total Short-Term Liabilities	$24.30M	$18.30M	$21.40M
Total Long-Term Liabilities	$47.60M	$47.40M	$46.70M
Total Liabilities	$3.996B	$3.989B	$3.303B
YoY Change	24.23%	20.75%	13.1%
SHAREHOLDERS EQUITY
Retained Earnings	$134.0M	$124.5M	$98.88M
YoY Change	24.3%	25.87%	23.17%
Common Stock	$302.0M	$301.9M	$304.1M
YoY Change	-0.99%	-0.71%	-2.71%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$441.6M	$431.9M	$407.2M
YoY Change
Total Liabilities & Shareholders Equity	$4.437B	$4.421B	$3.710B
YoY Change	22.14%	19.14%	12.43%

Cashflow Statement

Concept	2020 Q4	2020 Q3	2019 Q3
OPERATING ACTIVITIES
Net Income	$14.08M	$10.69M	$12.60M
YoY Change	5.74%	-15.19%	24.47%
Depreciation, Depletion And Amortization	$3.170M	$1.300M	$900.0K
YoY Change	24.31%	44.44%	0.0%
Cash From Operating Activities	$21.57M	$28.70M	$6.210M
YoY Change	-12.46%	362.16%	-54.14%
INVESTING ACTIVITIES
Capital Expenditures	-$1.790M	-$2.770M	-$3.750M
YoY Change	-59.04%	-26.13%	89.39%
Acquisitions
YoY Change
Other Investing Activities	$55.35M	-$37.55M	-$38.89M
YoY Change	-28.19%	-3.45%	-35.55%
Cash From Investing Activities	$53.56M	-$40.32M	-$42.64M
YoY Change	-26.33%	-5.44%	-31.59%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-3.720M	94.99M	114.5M
YoY Change	-95.96%	-17.07%	3630.94%
NET CHANGE
Cash From Operating Activities	21.57M	28.70M	6.210M
Cash From Investing Activities	53.56M	-40.32M	-42.64M
Cash From Financing Activities	-3.720M	94.99M	114.5M
Net Change In Cash	71.41M	83.37M	78.11M
YoY Change	1273.27%	6.73%	-270.84%
FREE CASH FLOW
Cash From Operating Activities	$21.57M	$28.70M	$6.210M
Capital Expenditures	-$1.790M	-$2.770M	-$3.750M
Free Cash Flow	$23.36M	$31.47M	$9.960M
YoY Change	-19.48%	215.96%	-35.82%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2019Q3	us-gaap	Other Noninterest Expense OtherNoninterestExpense	3679000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	11954000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	12134000	USD
CY2020Q3	us-gaap	Noninterest Expense NoninterestExpense	26423000	USD
CY2019Q3	us-gaap	Noninterest Expense NoninterestExpense	22027000	USD
	us-gaap	Noninterest Expense NoninterestExpense	72579000	USD
	us-gaap	Noninterest Expense NoninterestExpense	65944000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	13193000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	15554000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	37107000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	44615000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2507000	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2954000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	7051000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8476000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	10686000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	12600000	USD
	us-gaap	Net Income Loss NetIncomeLoss	30056000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36139000	USD
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.66
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.77
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.85
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.20
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.66
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.77
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.85
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.20
CY2020Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.28
CY2019Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.27
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.84
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.79
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16233196
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16390203
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	10686000	USD
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16265208
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16415843
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16233666
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16393078
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16265986
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16420845
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-532000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	12600000	USD
	us-gaap	Net Income Loss NetIncomeLoss	30056000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36139000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-675000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	1809000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	2352000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	15821000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-143000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	380000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	494000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	3323000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1429000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1858000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	12498000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	10154000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	14029000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	31914000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	48637000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	425221000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	12000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	206000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	45000	USD
CY2020Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	736000	USD
CY2020Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	4474000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	10686000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-532000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	431900000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	416561000	USD
	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	37000	USD
	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	610000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	394000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2102000	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	6282000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	13436000	USD
	us-gaap	Net Income Loss NetIncomeLoss	30056000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1858000	USD
CY2020Q3	us-gaap	Stockholders Equity StockholdersEquity	431900000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	400117000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	13000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	180000	USD
CY2019Q3	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	711000	USD
CY2019Q3	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	3508000	USD
CY2019Q3	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	4342000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	12600000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1429000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	407200000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	375249000	USD
	us-gaap	Stock Issued During Period Value Employee Stock Purchase Plan StockIssuedDuringPeriodValueEmployeeStockPurchasePlan	39000	USD
	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	541000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	16000	USD
	us-gaap	Stock Issued During Period Value Issued For Services StockIssuedDuringPeriodValueIssuedForServices	375000	USD
	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2199000	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	7110000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	12746000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36139000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	12498000	USD
CY2019Q3	us-gaap	Stockholders Equity StockholdersEquity	407200000	USD
	us-gaap	Net Income Loss NetIncomeLoss	30056000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36139000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	6262000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	6997000	USD
	mbwm	Discount Accretion On Acquired Loans DiscountAccretionOnAcquiredLoans	337000	USD
	mbwm	Discount Accretion On Acquired Loans DiscountAccretionOnAcquiredLoans	522000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	11550000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	2450000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2102000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	2199000	USD
	us-gaap	Issuance Of Stock And Warrants For Services Or Claims IssuanceOfStockAndWarrantsForServicesOrClaims	394000	USD
	us-gaap	Issuance Of Stock And Warrants For Services Or Claims IssuanceOfStockAndWarrantsForServicesOrClaims	375000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	505602000	USD
	us-gaap	Proceeds From Sale Of Mortgage Loans Held For Sale ProceedsFromSaleOfMortgageLoansHeldForSale	163056000	USD
	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	506683000	USD
	us-gaap	Payments For Origination Of Mortgage Loans Held For Sale PaymentsForOriginationOfMortgageLoansHeldForSale	169661000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	20055000	USD
	us-gaap	Gain Loss On Sale Of Mortgage Loans GainLossOnSaleOfMortgageLoans	5032000	USD
	mbwm	Net Gain Loss From Sale And Valuation Write Down Of Foreclosed Assets NetGainLossFromSaleAndValuationWriteDownOfForeclosedAssets	183000	USD
	mbwm	Net Gain Loss From Sale And Valuation Write Down Of Foreclosed Assets NetGainLossFromSaleAndValuationWriteDownOfForeclosedAssets	132000	USD
	mbwm	Net Gain Loss From Sale And Valuation Write Down Of Former Bank Premises NetGainLossFromSaleAndValuationWriteDownOfFormerBankPremises	27000	USD
	mbwm	Net Gain Loss From Sale And Valuation Write Down Of Former Bank Premises NetGainLossFromSaleAndValuationWriteDownOfFormerBankPremises	559000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-54000	USD
	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	-5000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	933000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	3567000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	1080000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	609000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	6269000	USD
	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	7163000	USD
	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	-4147000	USD
	us-gaap	Increase Decrease In Accrued Liabilities And Other Operating Liabilities IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities	-3843000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	16306000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	20133000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	472417000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	168412000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	270119000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	53353000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	296895000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	60617000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	313000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	632000	USD
	mbwm	Proceeds From Sale Of Former Bank Premises ProceedsFromSaleOfFormerBankPremises	162000	USD
	mbwm	Proceeds From Sale Of Former Bank Premises ProceedsFromSaleOfFormerBankPremises	854000	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	-0	USD
	us-gaap	Payments To Acquire Federal Home Loan Bank Stock PaymentsToAcquireFederalHomeLoanBankStock	1980000	USD
	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	-0	USD
	us-gaap	Payments To Acquire Life Insurance Policies PaymentsToAcquireLifeInsurancePolicies	2500000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	7708000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	7201000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	9109000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-452367000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-165543000	USD
	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	-65389000	USD
	us-gaap	Increase Decrease In Time Deposits IncreaseDecreaseInTimeDeposits	196035000	USD
	us-gaap	Increase Decrease In Other Deposits IncreaseDecreaseInOtherDeposits	747039000	USD
	us-gaap	Increase Decrease In Other Deposits IncreaseDecreaseInOtherDeposits	107348000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	54342000	USD
	us-gaap	Proceeds From Payments For In Securities Sold Under Agreements To Repurchase ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase	471000	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	20000000	USD
	us-gaap	Repayments Of Federal Home Loan Bank Borrowings RepaymentsOfFederalHomeLoanBankBorrowings	30000000	USD
	us-gaap	Proceeds From Federal Home Loan Bank Advances ProceedsFromFederalHomeLoanBankAdvances	60000000	USD
	us-gaap	Proceeds From Federal Home Loan Bank Advances ProceedsFromFederalHomeLoanBankAdvances	44000000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	0	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	16000	USD
	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	37000	USD
	us-gaap	Proceeds From Stock Plans ProceedsFromStockPlans	39000	USD
	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	610000	USD
	us-gaap	Proceeds From Issuance Of Common Stock Dividend Reinvestment Plan ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan	541000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	6282000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	7110000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	13436000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	12746000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	756921000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	298594000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	320860000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	153184000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	233731000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	75354000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	554591000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents And Federal Funds Sold CashCashEquivalentsAndFederalFundsSold	228538000	USD
	us-gaap	Interest Paid Net InterestPaidNet	21798000	USD
	us-gaap	Interest Paid Net InterestPaidNet	23361000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	7950000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	8875000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	146000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	227000	USD
	mbwm	Transfer Of Bank Premises To Other Real Estate Owned TransferOfBankPremisesToOtherRealEstateOwned	179000	USD
	mbwm	Transfer Of Bank Premises To Other Real Estate Owned TransferOfBankPremisesToOtherRealEstateOwned	0	USD
CY2020Q3	mbwm	Number Of Unconsolidated Business Trusts Formed To Issue Trust Preferred Securities NumberOfUnconsolidatedBusinessTrustsFormedToIssueTrustPreferredSecurities	5	pure
	mbwm	Interest Income On Commercial And Mortgage Loans Discontinued Period InterestIncomeOnCommercialAndMortgageLoansDiscontinuedPeriod	P90D
	mbwm	Maximum Delinquency Period For Consumer And Credit Card Loans To Be Charged Off MaximumDelinquencyPeriodForConsumerAndCreditCardLoansToBeChargedOff	P120D
CY2020Q3	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	27800000	USD
CY2019Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	5000000.0	USD
CY2020Q3	us-gaap	Servicing Asset ServicingAsset	958000000	USD
CY2019Q4	us-gaap	Servicing Asset ServicingAsset	727000000	USD
CY2020Q2	mbwm	Financing Receivable Advances Under Paycheck Protection Program Liquidity Facility FinancingReceivableAdvancesUnderPaycheckProtectionProgramLiquidityFacility	43700000	USD
CY2020Q3	mbwm	Financing Receivable Advances Under Paycheck Protection Program Liquidity Facility FinancingReceivableAdvancesUnderPaycheckProtectionProgramLiquidityFacility	0	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	305396000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	7543000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	515000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	312424000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	329979000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	5930000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	1254000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	334655000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	68002000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	514000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	32000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	1000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	68034000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	515000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	32243000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	395000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	85330000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	859000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	117573000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	1254000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	38	pure
CY2020Q3	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	68000000.0	USD
CY2020Q3	us-gaap	Other Than Temporary Impairment Credit Losses Recognized In Earnings Credit Losses On Debt Securities Held OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld	0	USD
CY2020Q3	mbwm	Weighted Average Yield Of Securities Portfolio Due In One Year Or Less WeightedAverageYieldOfSecuritiesPortfolioDueInOneYearOrLess	0.0408	pure
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Remainder Of Fiscal Year Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesRemainderOfFiscalYearAmortizedCostBasis	410000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Remainder Of Fiscal Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesRemainderOfFiscalYearFairValue	411000	USD
CY2020Q3	mbwm	Weighted Average Yield Of Securities Portfolio Due From One To Five Years WeightedAverageYieldOfSecuritiesPortfolioDueFromOneToFiveYears	0.0163	pure
CY2020Q3	mbwm	Debt Securities Availableforsale Amortized Cost Maturity Allocated And Single Maturity Date Year One Through Five DebtSecuritiesAvailableforsaleAmortizedCostMaturityAllocatedAndSingleMaturityDateYearOneThroughFive	70413000	USD
CY2020Q3	mbwm	Debt Securities Availableforsale Fair Value Maturity Allocated And Single Maturity Date Year One Through Five DebtSecuritiesAvailableforsaleFairValueMaturityAllocatedAndSingleMaturityDateYearOneThroughFive	71694000	USD
CY2020Q3	mbwm	Weighted Average Yield Of Securities Portfolio Due From Five To Ten Years WeightedAverageYieldOfSecuritiesPortfolioDueFromFiveToTenYears	0.0189	pure
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	138085000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	141743000	USD
CY2020Q3	mbwm	Weighted Average Yield Of Securities Portfolio Due Afterten Years WeightedAverageYieldOfSecuritiesPortfolioDueAftertenYears	0.0227	pure
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	68172000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	69173000	USD
CY2020Q3	mbwm	Weighted Average Yield Of Securities Portfolio WeightedAverageYieldOfSecuritiesPortfolio	0.0195	pure
CY2020Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	305396000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	312424000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	3350000000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	2860000000	USD
	mbwm	Loans And Leases Receivable Period Increase Decrease LoansAndLeasesReceivablePeriodIncreaseDecrease	494000000	USD
	mbwm	Loans And Leases Receivable Percentage Period Increase Decrease LoansAndLeasesReceivablePercentagePeriodIncreaseDecrease	0.173	pure
CY2020Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	3350544000	USD
CY2020Q3	mbwm	Loan Portfolio Classes And Segments As Percentage Of Aggregate Loan LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan	1.000	pure
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	2856667000	USD
CY2019Q4	mbwm	Loan Portfolio Classes And Segments As Percentage Of Aggregate Loan LoanPortfolioClassesAndSegmentsAsPercentageOfAggregateLoan	1.000	pure
	mbwm	Loans And Leases Receivable Net Of Deferred Income Increase Decrease Percentage LoansAndLeasesReceivableNetOfDeferredIncomeIncreaseDecreasePercentage	0.173	pure
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	2127000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	3348417000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	3350544000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	1884000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	2854783000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	2856667000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
CY2020Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	15774000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	13558000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	15506000	USD
	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	15459000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	2596000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	2547000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	910000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	2667000	USD
	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	2870000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	18370000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	16105000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	910000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	18173000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	18329000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	13687000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	12245000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	21098000	USD
	us-gaap	Impaired Financing Receivable With No Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment	17785000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	2398000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	2377000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1623000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	10798000	USD
	us-gaap	Impaired Financing Receivable With Related Allowance Average Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment	10446000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	16085000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	14622000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1623000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	31896000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	28231000	USD
CY2020Q3	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	200000	USD
CY2019Q3	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	500000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	800000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	900000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	100000	USD
	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	200000	USD
	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	100000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	32246000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	3200000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	123000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	249000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	35572000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	23889000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	11550000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	499000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	632000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	35572000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	910000	USD
CY2020Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	34662000	USD
CY2020Q3	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	3350544000	USD
CY2020Q3	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	16105000	USD
CY2020Q3	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	3334439000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	24053000	USD
CY2019Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	700000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	519000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	180000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	24414000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	22380000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	2450000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	771000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	355000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	24414000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	2345000	USD
CY2019Q3	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	22069000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	2856667000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	15056000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	2841611000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	12	pure
CY2020Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	784000	USD
CY2020Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	784000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	34	pure
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	11074000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	10478000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	9	pure
CY2019Q3	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	328000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	327000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	28	pure
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	16640000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	16938000	USD
	mbwm	Minimum Number Of Days Past Due At Period End For Loans Modified As Troubled Debt Restructurings MinimumNumberOfDaysPastDueAtPeriodEndForLoansModifiedAsTroubledDebtRestructurings	P30D
CY2020Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	pure
CY2020Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	pure
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	31000	USD
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	pure
CY2019Q3	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	1	pure
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	6000	USD
CY2020Q3	mbwm	Allowance For Credit Losses Troubled Debt Restructuring AllowanceForCreditLossesTroubledDebtRestructuring	490000	USD
CY2019Q4	mbwm	Allowance For Credit Losses Troubled Debt Restructuring AllowanceForCreditLossesTroubledDebtRestructuring	1578000	USD
CY2020Q3	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	96887000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	92598000	USD
CY2020Q3	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	36441000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	35271000	USD
CY2020Q3	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	60446000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	57327000	USD
CY2020Q3	us-gaap	Depreciation Depreciation	1300000	USD
CY2019Q3	us-gaap	Depreciation Depreciation	900000	USD
	us-gaap	Depreciation Depreciation	3800000	USD
	us-gaap	Depreciation Depreciation	2800000	USD
CY2020Q3	us-gaap	Deposits Deposits	3370000000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	682000000	USD
	mbwm	Aggregate Increase Decrease In Percentage Of Deposits AggregateIncreaseDecreaseInPercentageOfDeposits	0.253	pure
CY2020Q3	us-gaap	Noninterest Bearing Domestic Deposit Demand NoninterestBearingDomesticDepositDemand	1449879000	USD
CY2020Q3	mbwm	Percentage Of Non Interest Bearing Domestic Deposits To Deposits Demand PercentageOfNonInterestBearingDomesticDepositsToDepositsDemand	0.430	pure
CY2019Q4	us-gaap	Noninterest Bearing Domestic Deposit Demand NoninterestBearingDomesticDepositDemand	924916000	USD
CY2019Q4	mbwm	Percentage Of Non Interest Bearing Domestic Deposits To Deposits Demand PercentageOfNonInterestBearingDomesticDepositsToDepositsDemand	0.344	pure
	mbwm	Percentage Of Increase Decrease In Non Interest Bearing Demand Deposits PercentageOfIncreaseDecreaseInNonInterestBearingDemandDeposits	0.568	pure
CY2020Q3	us-gaap	Interest Bearing Domestic Deposit Checking InterestBearingDomesticDepositChecking	439925000	USD
CY2020Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Checking PercentageOfInterestBearingDomesticDepositsToDepositsChecking	0.130	pure
CY2019Q4	us-gaap	Interest Bearing Domestic Deposit Checking InterestBearingDomesticDepositChecking	332373000	USD
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Checking PercentageOfInterestBearingDomesticDepositsToDepositsChecking	0.123	pure
	mbwm	Percentage Of Increase Decrease Of Interest Bearing Checking Deposits PercentageOfIncreaseDecreaseOfInterestBearingCheckingDeposits	0.324	pure
CY2020Q3	us-gaap	Interest Bearing Domestic Deposit Money Market InterestBearingDomesticDepositMoneyMarket	575077000	USD
CY2020Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.171	pure
CY2019Q4	us-gaap	Interest Bearing Domestic Deposit Money Market InterestBearingDomesticDepositMoneyMarket	509368000	USD
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Money Market PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket	0.189	pure
	mbwm	Percentage Of Increase Decrease In Money Market Deposits PercentageOfIncreaseDecreaseInMoneyMarketDeposits	0.129	pure
CY2020Q3	us-gaap	Interest Bearing Domestic Deposit Savings InterestBearingDomesticDepositSavings	318132000	USD
CY2020Q3	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.094	pure
CY2019Q4	us-gaap	Interest Bearing Domestic Deposit Savings InterestBearingDomesticDepositSavings	269318000	USD
CY2019Q4	us-gaap	Percentage Of Interest Bearing Domestic Deposits To Deposits Savings PercentageOfInterestBearingDomesticDepositsToDepositsSavings	0.100	pure
	mbwm	Percentage Of Increase Or Decrease Of Savings Deposits PercentageOfIncreaseOrDecreaseOfSavingsDeposits	0.181	pure
CY2020Q3	mbwm	Domestic Time Deposits Less Than100000 DomesticTimeDepositsLessThan100000	173193000	USD
CY2020Q3	mbwm	Percentage Of Domestic Time Deposits Under100000 PercentageOfDomesticTimeDepositsUnder100000	0.051	pure
CY2019Q4	mbwm	Domestic Time Deposits Less Than100000 DomesticTimeDepositsLessThan100000	198123000	USD
CY2019Q4	mbwm	Percentage Of Domestic Time Deposits Under100000 PercentageOfDomesticTimeDepositsUnder100000	0.074	pure
	mbwm	Percentage Of Increase Decrease In Domestic Time Deposits Under100000 PercentageOfIncreaseDecreaseInDomesticTimeDepositsUnder100000	-0.126	pure
CY2020Q3	mbwm	Domestic Time Deposits100000 Or More DomesticTimeDeposits100000OrMore	349867000	USD
CY2020Q3	mbwm	Percentage Of Domestic Time Deposits100000 And Over PercentageOfDomesticTimeDeposits100000AndOver	0.104	pure
CY2019Q4	mbwm	Domestic Time Deposits100000 Or More DomesticTimeDeposits100000OrMore	322827000	USD
CY2019Q4	mbwm	Percentage Of Domestic Time Deposits100000 And Over PercentageOfDomesticTimeDeposits100000AndOver	0.120	pure
	mbwm	Percentage Of Increase Decrease In Domestic Time Deposits100000 And Over PercentageOfIncreaseDecreaseInDomesticTimeDeposits100000AndOver	0.084	pure
CY2020Q3	mbwm	Aggregate Local Deposit Liabilities AggregateLocalDepositLiabilities	3306073000	USD
CY2020Q3	mbwm	Aggregate Percentage Of Local Deposits AggregatePercentageOfLocalDeposits	0.980	pure
CY2019Q4	mbwm	Aggregate Local Deposit Liabilities AggregateLocalDepositLiabilities	2556925000	USD
CY2019Q4	mbwm	Aggregate Percentage Of Local Deposits AggregatePercentageOfLocalDeposits	0.950	pure
	mbwm	Aggregate Percentage Increase Decrease In Local Deposits AggregatePercentageIncreaseDecreaseInLocalDeposits	0.293	pure
CY2020Q3	mbwm	Out Of Area Time Deposits Under100000 OutOfAreaTimeDepositsUnder100000	0	USD
CY2019Q4	mbwm	Out Of Area Time Deposits Under100000 OutOfAreaTimeDepositsUnder100000	0	USD
CY2020Q3	mbwm	Out Of Area Time Deposits100000 And Over OutOfAreaTimeDeposits100000AndOver	65961000	USD
CY2020Q3	mbwm	Percentage Of Out Of Area Time Deposits100000 And Over PercentageOfOutOfAreaTimeDeposits100000AndOver	0.020	pure
CY2019Q4	mbwm	Out Of Area Time Deposits100000 And Over OutOfAreaTimeDeposits100000AndOver	133459000	USD
CY2019Q4	mbwm	Percentage Of Out Of Area Time Deposits100000 And Over PercentageOfOutOfAreaTimeDeposits100000AndOver	0.050	pure
	mbwm	Percentage Of Increase Decrease In Out Of Area Time100000 And Over PercentageOfIncreaseDecreaseInOutOfAreaTime100000AndOver	-0.506	pure
CY2020Q3	mbwm	Aggregate Out Of Area Time Deposits AggregateOutOfAreaTimeDeposits	65961000	USD
CY2020Q3	mbwm	Aggregate Percentage Of Out Of Area Deposits AggregatePercentageOfOutOfAreaDeposits	0.020	pure
CY2019Q4	mbwm	Aggregate Out Of Area Time Deposits AggregateOutOfAreaTimeDeposits	133459000	USD
CY2019Q4	mbwm	Aggregate Percentage Of Out Of Area Deposits AggregatePercentageOfOutOfAreaDeposits	0.050	pure
	mbwm	Aggregate Percentage Increase Decrease In Out Of Area Deposits AggregatePercentageIncreaseDecreaseInOutOfAreaDeposits	-0.506	pure
CY2020Q3	us-gaap	Deposits Deposits	3372034000	USD
CY2020Q3	mbwm	Aggregate Percentage Of Deposits AggregatePercentageOfDeposits	1.000	pure
CY2019Q4	us-gaap	Deposits Deposits	2690384000	USD
CY2019Q4	mbwm	Aggregate Percentage Of Deposits AggregatePercentageOfDeposits	1.000	pure
	mbwm	Aggregate Increase Decrease In Percentage Of Deposits AggregateIncreaseDecreaseInPercentageOfDeposits	0.253	pure
CY2020Q3	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	294000000	USD
CY2019Q4	us-gaap	Time Deposits At Or Above Fdic Insurance Limit TimeDepositsAtOrAboveFDICInsuranceLimit	320000000	USD
	us-gaap	Schedule Of Repurchase Agreements ScheduleOfRepurchaseAgreements	<table border="0" cellpadding="0" cellspacing="0" class="finTable" style="margin-right: 5%; margin-left: 18pt; width: 95%; font-size: 10pt; font-family: "Times New Roman", Times, serif; text-indent: 0px;"> <tbody> <tr style="vertical-align: bottom;"> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td colspan="2" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid rgb(0, 0, 0);"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">Nine Months</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">Ended</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">September 30,</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">2020</p> </td> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; padding-bottom: 1px;"> </td> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td colspan="2" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid rgb(0, 0, 0);"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">Twelve Months</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">Ended</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">December 31,</p> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">2019</p> </td> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; padding-bottom: 1px;"> </td> </tr> <tr style="vertical-align: bottom;"> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; width: 68%;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;">Outstanding balance at end of period</p> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">157,017,000</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">102,675,000</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(255, 255, 255);"> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;">Average interest rate at end of period</p> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">0.11</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:left;">%</p> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">0.17</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:left;">%</p> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(255, 255, 255);"> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;">Average daily balance during the period</p> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">129,091,000</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">105,234,000</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(255, 255, 255);"> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;">Average interest rate during the period</p> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">0.12</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:left;">%</p> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">0.24</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:left;">%</p> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> </tr> <tr style="vertical-align: bottom; background-color: rgb(255, 255, 255);"> <td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;">Maximum daily balance during the period</p> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">173,142,000</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td> <td style="width: 13%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">133,411,000</td> <td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td> </tr> </tbody> </table>
CY2020Q3	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	157017000	USD
CY2019Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	102675000	USD
	us-gaap	Shortterm Debt Average Outstanding Amount ShorttermDebtAverageOutstandingAmount	129091000	USD
CY2019	us-gaap	Shortterm Debt Average Outstanding Amount ShorttermDebtAverageOutstandingAmount	105234000	USD
	us-gaap	Shortterm Debt Maximum Amount Outstanding During Period ShorttermDebtMaximumAmountOutstandingDuringPeriod	173142000	USD
CY2019	us-gaap	Shortterm Debt Maximum Amount Outstanding During Period ShorttermDebtMaximumAmountOutstandingDuringPeriod	133411000	USD
CY2020Q3	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	737000000	USD
CY2020Q3	us-gaap	Line Of Credit Facility Remaining Borrowing Capacity LineOfCreditFacilityRemainingBorrowingCapacity	337000000	USD
CY2020Q3	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due In Remainder Of Fiscal Year FederalHomeLoanBankAdvancesMaturitiesSummaryDueInRemainderOfFiscalYear	0	USD
CY2020Q3	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	20000000	USD
CY2020Q3	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From One To Two Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromOneToTwoYearsOfBalanceSheetDate	94000000	USD
CY2020Q3	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Two To Three Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromTwoToThreeYearsOfBalanceSheetDate	80000000	USD
CY2020Q3	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due From Three To Four Years Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueFromThreeToFourYearsOfBalanceSheetDate	80000000	USD
CY2020Q3	mbwm	Federal Home Loan Bank Advance Maturity After Year Four FederalHomeLoanBankAdvanceMaturityAfterYearFour	120000000	USD
CY2019Q4	mbwm	Reserve Or Liability Balance For Financial Instruments With Off Balance Sheet Risk ReserveOrLiabilityBalanceForFinancialInstrumentsWithOffBalanceSheetRisk	0	USD
CY2020Q3	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	1361418000	USD
CY2019Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Amount Liability FairValueDisclosureOffbalanceSheetRisksAmountLiability	1038444000	USD
CY2020Q3	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	27800000	USD
CY2019Q4	us-gaap	Loans Receivable Held For Sale Net Not Part Of Disposal Group LoansReceivableHeldForSaleNetNotPartOfDisposalGroup	5000000.0	USD
CY2020Q3	mbwm	Preferred Securities Of Subsidiary Trust PreferredSecuritiesOfSubsidiaryTrust	45300000	USD
CY2019Q4	mbwm	Preferred Securities Of Subsidiary Trust PreferredSecuritiesOfSubsidiaryTrust	44800000	USD
	mbwm	Maximum Restricted Core Element Allowed In Tier One Capital Percent MaximumRestrictedCoreElementAllowedInTierOneCapitalPercent	0.25	pure
CY2009Q4	mbwm	Maximum Level Of Consolidated Aggregate Assets Allowing For Inclusion Of Trust Preferred Securities In Tier One Capital MaximumLevelOfConsolidatedAggregateAssetsAllowingForInclusionOfTrustPreferredSecuritiesInTierOneCapital	15000000000.0	USD
CY2020Q3	mbwm	Trust Preferred Securities Included In Tier One Capital TrustPreferredSecuritiesIncludedInTierOneCapital	45300000	USD
CY2019Q4	mbwm	Trust Preferred Securities Included In Tier One Capital TrustPreferredSecuritiesIncludedInTierOneCapital	44800000	USD
CY2020Q3	mbwm	Capital Conservation Buffer CapitalConservationBuffer	0.025	pure
CY2020Q3	mbwm	Common Equity Tier1 Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets CommonEquityTier1RiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.070	pure
CY2020Q3	us-gaap	Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.085	pure
CY2020Q3	us-gaap	Capital Required For Capital Adequacy To Risk Weighted Assets CapitalRequiredForCapitalAdequacyToRiskWeightedAssets	0.105	pure
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.28
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.28
CY2019Q2	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	20000000.0	USD
CY2020Q1	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	222385
CY2020Q1	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	6300000	USD
CY2020Q2	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	0	USD
	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	1600000
	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	38900000	USD
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	24.13
CY2020Q3	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	10100000	USD

Files In Submission

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0001437749-20-022892-index-headers.html	Edgar Link	pending
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0001437749-20-022892.txt	Edgar Link	pending
0001437749-20-022892-xbrl.zip	Edgar Link	pending
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Financial_Report.xlsx	Edgar Link	pending
mbwm-20200930.xsd	Edgar Link	pending
mbwm-20200930_cal.xml	Edgar Link	unprocessable
mbwm-20200930_def.xml	Edgar Link	unprocessable
mbwm-20200930_lab.xml	Edgar Link	unprocessable
mbwm-20200930_pre.xml	Edgar Link	unprocessable
mbwm20200930_10q.htm	Edgar Link	pending
mbwm20200930_10q_htm.xml	Edgar Link	completed
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2020 Q4 Form 10-Q Financial Statement

#000143774920022892 Filed on November 06, 2020

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2020 Q4 Form 10-Q Financial Statement

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