XML 55 R45.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Note 3 - Loans and Allowance for Loan Losses - Activity in Allowance for Loan Losses and the Recorded Investments in Loans (Details) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015 | Dec. 31, 2015
Originated Loan [Member] | Commercial Portfolio Segment [Member] |  |  |  |  |
Balance | $ 13,924,000 | $ 18,977,000 | $ 13,672,000 | $ 17,736,000 |
Provision for loan losses | 842,000 | (1,151,000) | 936,000 | (1,651,000) |
Charge-offs | (166,000) | (4,199,000) | (255,000) | (4,277,000) |
Recoveries | 129,000 | 365,000 | 376,000 | 2,184,000 |
Ending balance | 14,729,000 | 13,992,000 | 14,729,000 | 13,992,000 |
Ending balance: individually evaluated for impairment | 827,000 | 2,146,000 | 827,000 | 2,146,000 |
Ending balance: collectively evaluated for impairment | 13,902,000 | 11,846,000 | 13,902,000 | 11,846,000 |
Loans | 1,664,745,000 | 1,322,388,000 | 1,664,745,000 | 1,322,388,000 | $ 1,493,516,000
Ending balance: individually evaluated for impairment | 16,905,000 | 19,108,000 | 16,905,000 | 19,108,000 |
Ending balance: collectively evaluated for impairment | 1,647,840,000 | 1,303,280,000 | 1,647,840,000 | 1,303,280,000 |
Originated Loan [Member] | Retail Portfolio Segment [Member] |  |  |  |  |
Balance | 1,834,000 | 1,235,000 | 1,421,000 | 1,487,000 |
Provision for loan losses | 296,000 | 513,000 | 799,000 | 592,000 |
Charge-offs | (231,000) | (154,000) | (617,000) | (517,000) |
Recoveries | 14,000 | 120,000 | 310,000 | 152,000 |
Ending balance | 1,913,000 | 1,714,000 | 1,913,000 | 1,714,000 |
Ending balance: individually evaluated for impairment | 209,000 | 178,000 | 209,000 | 178,000 |
Ending balance: collectively evaluated for impairment | 1,704,000 | 1,536,000 | 1,704,000 | 1,536,000 |
Loans | 135,209,000 | 107,235,000 | 135,209,000 | 107,235,000 | 123,071,000
Ending balance: individually evaluated for impairment | 1,463,000 | 1,180,000 | 1,463,000 | 1,180,000 |
Ending balance: collectively evaluated for impairment | 133,746,000 | 106,055,000 | 133,746,000 | 106,055,000 |
Originated Loan [Member] | Unallocated Financing Receivables [Member] |  |  |  |  |
Balance | 214,000 | 39,000 | 140,000 | 76,000 |
Provision for loan losses | 20,000 | (5,000) | 94,000 | (42,000) |
Charge-offs | 0 | 0 | 0 | 0 |
Recoveries | 0 | 0 | 0 | 0 |
Ending balance | 234,000 | 34,000 | 234,000 | 34,000 |
Ending balance: individually evaluated for impairment | 0 | 0 | 0 | 0 |
Ending balance: collectively evaluated for impairment | 234,000 | 34,000 | 234,000 | 34,000 |
Loans |  |  |  |  |
Originated Loan [Member] |  |  |  |  |
Balance | 15,972,000 | 20,251,000 | 15,233,000 | 19,299,000 |
Provision for loan losses | 1,158,000 | (643,000) | 1,829,000 | (1,101,000) |
Charge-offs | (397,000) | (4,353,000) | (872,000) | (4,794,000) |
Recoveries | 143,000 | 485,000 | 686,000 | 2,336,000 |
Ending balance | 16,876,000 | 15,740,000 | 16,876,000 | 15,740,000 |
Ending balance: individually evaluated for impairment | 1,036,000 | 2,324,000 | 1,036,000 | 2,324,000 |
Ending balance: collectively evaluated for impairment | 15,840,000 | 13,416,000 | 15,840,000 | 13,416,000 |
Loans | 1,799,954,000 | 1,429,623,000 | 1,799,954,000 | 1,429,623,000 | 1,616,587,000
Ending balance: individually evaluated for impairment | 18,368,000 | 20,288,000 | 18,368,000 | 20,288,000 |
Ending balance: collectively evaluated for impairment | 1,781,586,000 | 1,409,335,000 | 1,781,586,000 | 1,409,335,000 |
Acquired Loan [Member] | Commercial Portfolio Segment [Member] |  |  |  |  |
Balance | 266,000 | 622,000 | 420,000 | 681,000 |
Provision for loan losses | (57,000) | (31,000) | (167,000) | (90,000) |
Charge-offs | 0 | (30,000) | 0 | (31,000) |
Recoveries | 2,000 | 0 |  | 1,000 |
Ending balance | 211,000 | 561,000 | 211,000 | 561,000 |
Loans | 395,010,000 |  | 395,010,000 |  | 453,180,000
Recoveries |  |  | (42,000) |  |
Acquired Loan [Member] | Retail Portfolio Segment [Member] |  |  |  |  |
Balance | 24,000 | 177,000 | 28,000 | 61,000 |
Provision for loan losses | (1,000) | 74,000 | 38,000 | 191,000 |
Charge-offs | 0 | 0 | 0 | (7,000) |
Recoveries | 0 | 9,000 |  | 15,000 |
Ending balance | 23,000 | 260,000 | 23,000 | 260,000 |
Loans | 184,976,000 |  | 184,976,000 |  | 207,960,000
Recoveries |  |  | (43,000) |  |
Acquired Loan [Member] | Unallocated Financing Receivables [Member] |  |  |  |  |
Balance | 0 | 0 | 0 | 0 |
Provision for loan losses | 0 | 0 | 0 | 0 |
Charge-offs | 0 | 0 | 0 | 0 |
Recoveries | 0 | 0 |  | 0 |
Ending balance | 0 | 0 | 0 | 0 |
Recoveries |  |  | 0 |  |
Acquired Loan [Member] |  |  |  |  |
Balance | 290,000 | 799,000 | 448,000 | 742,000 |
Provision for loan losses | (58,000) | 43,000 | (129,000) | 101,000 |
Charge-offs | 0 | (30,000) | 0 | (38,000) |
Recoveries | 2,000 | 9,000 |  | 16,000 |
Ending balance | 234,000 | 821,000 | 234,000 | 821,000 |
Loans | 579,986,000 |  | 579,986,000 |  | 661,140,000
Recoveries |  |  | (85,000) |  |
Commercial Portfolio Segment [Member] |  |  |  |  |
Loans | 2,059,755,000 |  | 2,059,755,000 |  | 1,946,696,000
Retail Portfolio Segment [Member] |  |  |  |  |
Loans | 320,185,000 |  | 320,185,000 |  | 331,031,000
Provision for loan losses | 1,100,000 | $ (600,000) | 1,700,000 | $ (1,000,000) |
Loans | $ 2,379,940,000 |  | $ 2,379,940,000 |  | $ 2,277,727,000

X
- Definition Amount of recovery of financing receivables doubtful of collection that are reversed during the period. + References No definition available. + Details
Name: | mbwm_FinancingReceivableAllowanceForCreditLossesRecoveryReversal
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A valuation allowance for financing receivables that are expected to be uncollectible. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of recovery of financing receivables doubtful of collection that were previously charged off. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(4) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of direct write-downs of financing receivables charged against the allowance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The balance of financing receivables that were collectively evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The balance of financing receivables that were individually evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524 + Details
Name: | us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of expense related to estimated loss from loan and lease transactions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.11) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_ProvisionForLoanAndLeaseLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
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_FinancingReceivablePortfolioSegmentAxis=us-gaap_UnallocatedFinancingReceivablesMember
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: |