XML 48 R59.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Fair Values (Details) (USD $) | Jun. 30, 2012 | Dec. 31, 2011
--- | --- | ---
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | $ 127,591,000 | $ 172,992,000
Fair Value, Measurements, Recurring [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Assets and liabilities measured at fair value on recurring basis | 127,011,000 | 173,249,000
Fair Value, Measurements, Recurring [Member] | Interest rate swap agreement [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | (647,000) |
Fair Value, Measurements, Recurring [Member] | Interest rate cap contracts [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | 67,000 | 257,000
Fair Value, Measurements, Recurring [Member] | U.S. Government agency debt obligations [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 59,836,000 | 88,596,000
Fair Value, Measurements, Recurring [Member] | Mortgage-backed securities [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 28,053,000 | 34,610,000
Fair Value, Measurements, Recurring [Member] | Michigan Strategic Fund bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 11,360,000 | 16,700,000
Fair Value, Measurements, Recurring [Member] | Municipal general obligation bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 24,082,000 | 27,309,000
Fair Value, Measurements, Recurring [Member] | Municipal revenue bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 2,873,000 | 4,423,000
Fair Value, Measurements, Recurring [Member] | Mutual funds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 1,387,000 | 1,354,000
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Assets and liabilities measured at fair value on recurring basis | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Interest rate swap agreement [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | 0 |
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Interest rate cap contracts [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Government agency debt obligations [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Mortgage-backed securities [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Michigan Strategic Fund bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Municipal general obligation bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Municipal revenue bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Mutual funds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Assets and liabilities measured at fair value on recurring basis | 127,011,000 | 173,249,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Interest rate swap agreement [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | (647,000) |
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Interest rate cap contracts [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | 67,000 | 257,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Government agency debt obligations [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 59,836,000 | 88,596,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Mortgage-backed securities [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 28,053,000 | 34,610,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Michigan Strategic Fund bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 11,360,000 | 16,700,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Municipal general obligation bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 24,082,000 | 27,309,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Municipal revenue bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 2,873,000 | 4,423,000
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Mutual funds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 1,387,000 | 1,354,000
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Assets and liabilities measured at fair value on recurring basis | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Interest rate swap agreement [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | 0 |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Interest rate cap contracts [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Derivatives | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | U.S. Government agency debt obligations [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Mortgage-backed securities [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Michigan Strategic Fund bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Municipal general obligation bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Municipal revenue bonds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | 0 | 0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Mutual funds [Member] |  |
Assets and Liabilities Measured at Fair Value on a Recurring Basis |  |
Fair Value of Available for sale securities | $ 0 | $ 0

X
- Definition Balances of assets and liabilities measured at fair value on recurring basis. + References No definition available. + Details
Name: | mbwm_BalancesOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasis
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph b -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 + Details
Name: | us-gaap_AvailableForSaleSecuritiesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 107 -Paragraph 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 4, 17 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration