XML 62 R53.htm IDEA: XBRL DOCUMENT
v3.22.1

Note 4 - Premises and Equipment, Net (Details Textual) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2022 | Mar. 31, 2021 | Dec. 31, 2021
Depreciation, Total | $ 1.6 | $ 1.4 |
Operating Lease, Weighted Average Remaining Lease Term (Year) | 2 years 7 months 6 days |  | 2 years 9 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent | 4.70% |  | 4.70%
Operating Lease, Expense | $ 0.2 | $ 0.2 |
Lessee, Operating Lease, Liability, to be Paid, Total | 3.4 |  | $ 3.6
Lessee, Operating Lease, Liability, to be Paid, Year One | 0.8 |  | 0.8
Lessee, Operating Lease, Liability, to be Paid, Year Two and Year Three | 1.2 |  | 1.4
Lessee, Operating Lease, Liability, to be Paid, Year Four and Year Five | 0.3 |  | 0.3
Lessee, Operating Lease, Liability, to be Paid, after Year Five | 1.1 |  | 1.1
Premises and Equipment, Net [Member] |  |  |
Operating Lease, Right-of-Use Asset | 2.6 |  | 2.9
Other Liabilities [Member] |  |  |
Operating Lease, Liability, Total | $ 2.6 |  | $ 2.9
Minimum [Member] |  |  |
Lessee, Operating Lease, Renewal Term (Year) | 3 years |  |
Maximum [Member] |  |  |
Lessee, Operating Lease, Renewal Term (Year) | 5 years |  |

X
- Definition Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth and fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References No definition available. + Details
Name: | mbwm_LesseeOperatingLeaseLiabilityToBePaidYearFourAndYearFive
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second and third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References No definition available. + Details
Name: | mbwm_LesseeOperatingLeaseLiabilityToBePaidYearTwoAndYearThree
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585 + Details
Name: | us-gaap_Depreciation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of lessee's undiscounted obligation for lease payment for operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payment for operating lease due after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseRenewalTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of operating lease expense. Excludes sublease income. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 4 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918638-209977 + Details
Name: | us-gaap_OperatingLeaseExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average discount rate for operating lease calculated at point in time. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(4) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 + Details
Name: | us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(3) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980 + Details
Name: | us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=mbwm_PremisesAndEquipmentNetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |