XML 45 R35.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Note 2 - Securities- Securities in a Continuous Loss Position (Details) - USD ($) | Sep. 30, 2016 | Dec. 31, 2015
--- | --- | ---
US Government Agencies Debt Securities [Member] |  |
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Fair Value | $ 52,728,000 | $ 0
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Unrealized Loss | 633,000 | 0
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Fair Value | 1,992,000 | 76,496,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Unrealized Loss | 8,000 | 1,552,000
Available for Sale Securities in a Continuous Loss Position, Fair Value | 54,720,000 | 76,496,000
Available for Sale Securities in a Continuous Loss Position, Unrealized Loss | 641,000 | 1,552,000
Collateralized Mortgage Backed Securities [Member] |  |
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Fair Value | 787,000 | 18,025,000
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Unrealized Loss | 3,000 | 69,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Fair Value | 15,064,000 | 34,660,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Unrealized Loss | 55,000 | 235,000
Available for Sale Securities in a Continuous Loss Position, Fair Value | 15,851,000 | 52,685,000
Available for Sale Securities in a Continuous Loss Position, Unrealized Loss | 58,000 | 304,000
Municipal General Obligation Bonds [Member] |  |
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Fair Value | 14,524,000 | 1,981,000
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Unrealized Loss | 86,000 | 4,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Fair Value | 6,644,000 | 30,134,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Unrealized Loss | 78,000 | 201,000
Available for Sale Securities in a Continuous Loss Position, Fair Value | 21,168,000 | 32,115,000
Available for Sale Securities in a Continuous Loss Position, Unrealized Loss | 164,000 | 205,000
Municipal Revenue Bonds [Member] |  |
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Fair Value | 1,502,000 | 0
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Unrealized Loss | 10,000 | 0
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Fair Value | 0 | 1,134,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Unrealized Loss | 0 | 3,000
Available for Sale Securities in a Continuous Loss Position, Fair Value | 1,502,000 | 1,134,000
Available for Sale Securities in a Continuous Loss Position, Unrealized Loss | 10,000 | 3,000
Other Debt Obligations [Member] |  |
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Fair Value | 0 | 1,446,000
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Unrealized Loss | 0 | 5,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Fair Value | 0 | 0
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Unrealized Loss | 0 | 0
Available for Sale Securities in a Continuous Loss Position, Fair Value | 0 | 1,446,000
Available for Sale Securities in a Continuous Loss Position, Unrealized Loss | 0 | 5,000
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Fair Value | 69,541,000 | 21,452,000
Available for Sale Securities in a Continuous Loss Position, Less than 12 months Unrealized Loss | 732,000 | 78,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Fair Value | 23,700,000 | 142,424,000
Available for Sale Securities in a Continuous Loss Position, 12 Months or More Unrealized Loss | 141,000 | 1,991,000
Available for Sale Securities in a Continuous Loss Position, Fair Value | 93,241,000 | 163,876,000
Available for Sale Securities in a Continuous Loss Position, Unrealized Loss | $ 873,000 | $ 2,069,000

X
- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for twelve months or longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=mbwm_MunicipalGeneralObligationBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=mbwm_MunicipalRevenueBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |