XML 74 R49.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Deposits (Details) (USD $) | 6 Months Ended |
--- | --- | ---
Jun. 30, 2012 | Dec. 31, 2011
The components of outstanding balances and percentage change in deposits |  |
Noninterest-bearing demand | $ 164,532,000 | $ 147,031,000
Interest-bearing checking | 174,200,000 | 179,770,000
Money market | 152,646,000 | 145,402,000
Savings | 32,797,000 | 32,468,000
Time, under $100,000 | 59,069,000 | 63,330,000
Time, $100,000 and over | 214,105,000 | 213,548,000
Total Local Deposits | 797,349,000 | 781,549,000
Percentage of Noninterest-bearing demand | 14.90% | 13.20%
Percentage of Interest-bearing checking | 15.70% | 16.20%
Percentage of Money market | 13.80% | 13.10%
Percentage of Savings | 3.00% | 2.90%
Percentage of time deposits, under $100,000 | 5.30% | 5.70%
Percentage of time deposits, $100,000 and over | 19.40% | 19.20%
Percentage of total local deposits | 72.10% | 70.30%
Percentage of Increase or (Decrease) in Noninterest-bearing demand | 11.90% |
Percentage of Increase or (Decrease) of Interest-bearing checking Deposits | (3.10%) |
Percentage of Increase or (Decrease) of Money market Deposits | 5.00% |
Percentage of Increase or (Decrease) of Savings Deposits | 1.00% |
Percentage of Increase or (Decrease) in Time Deposits, under $100,000 | (6.70%) |
Percentage of Increase or (Decrease) in Time Deposits, $100,000 and over | 0.30% |
Percentage of Increase or (Decrease) in Local Deposits | 2.00% |
Out-of-area interest-bearing checking | 23,532,000 | 26,142,000
Out-of-area time, under $100,000 | 10,864,000 | 18,457,000
Out-of-area time, $100,000 and over | 273,885,000 | 285,927,000
Total out-of-area deposits | 308,281,000 | 330,526,000
Percentage of out-of-area interest- bearing checking | 2.10% | 2.30%
Percentage of out-of-area time, under $100,000 | 1.00% | 1.70%
Percentage of out-of-area time, $100,000 and over | 24.80% | 25.70%
Aggregate percentage of out-of-area deposits | 27.90% | 29.70%
Percentage of Increase or (Decrease) in out-of-area interest-bearing checking | (10.00%) |
Percentage of Increase or (Decrease) in out-of- area time, under $100,000 | (41.10%) |
Percentage Increase or (Decrease) in out-of-area time, $100,000 and over | (4.20%) |
Aggregate Percentage Increase or (Decrease) in out-of-area deposits | (6.70%) |
Total deposits | $ 1,105,630,000 | $ 1,112,075,000
Aggregate percentage of total deposits | 100.00% | 100.00%
Aggregate Percentage Increase or (Decrease) in Total Deposits | (0.60%) |

X
- Definition Aggregate percentage increase or decrease in total deposits. + References No definition available. + Details
Name: | mbwm_AggregateIncreaseOrDecreaseInPercentageOfDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate local deposit liabilities. + References No definition available. + Details
Name: | mbwm_AggregateLocalDepositLiabilities
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Aggregate out of area time deposits. + References No definition available. + Details
Name: | mbwm_AggregateOutOfAreaTimeDeposits
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate percentage increase or decrease in local deposits. + References No definition available. + Details
Name: | mbwm_AggregatePercentageIncreaseOrDecreaseInLocalDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate percentage increase or decrease in out-of-area deposits. + References No definition available. + Details
Name: | mbwm_AggregatePercentageIncreaseOrDecreaseInOutOfAreaDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate percentage of total deposits. + References No definition available. + Details
Name: | mbwm_AggregatePercentageOfDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate percentage of local Deposits. + References No definition available. + Details
Name: | mbwm_AggregatePercentageOfLocalDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate percentage of out-of-area deposits. + References No definition available. + Details
Name: | mbwm_AggregatePercentageOfOutOfAreaDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | mbwm_ComponentsOfBankDepositsAbstract
Namespace Prefix: | mbwm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Out of area interest bearing checking. + References No definition available. + Details
Name: | mbwm_OutOfAreaInterestBearingChecking
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Out-of-area time, $100,000 and over. + References No definition available. + Details
Name: | mbwm_OutOfAreaTimeEqualToGreaterThan100000
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Out-of-area time, under $100,000. + References No definition available. + Details
Name: | mbwm_OutOfAreaTimeLessThan100000
Namespace Prefix: | mbwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of increase or decrease in noninterest-bearing demand deposits. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseInNonInterestBearingDemandDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase or decrease in out of area interest bearing checking. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseInOutOfAreaInterestBearingChecking
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase or decrease in out of area time equal to greater than one lakh. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseInOutOfAreaTimeEqualToGreaterThanOneLakh
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase or decrease in out of area time, under $100,000. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseInOutOfAreaTimeLessThan100000
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of Increase or Decrease in Time Deposits, $100,000 and over. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseInTimeDepositsEqualToGreaterThan100000
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase or decrease in time deposits less than 100000. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseInTimeDepositsLessThan100000
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase or decrease of interest-bearing checking deposits. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseOfInterestBearingCheckingDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase or decrease of money market deposits. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseOfMoneyMarketDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of increase or decrease of savings deposits. + References No definition available. + Details
Name: | mbwm_PercentageOfIncreaseOrDecreaseOfSavingsDeposits
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of noninterest-bearing domestic demand deposit liabilities to total deposit liabilities. + References No definition available. + Details
Name: | mbwm_PercentageOfNonInterestBearingDomesticDepositsToDepositsDemand
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage Of Out-Of-Area Interest- Bearing Checking. + References No definition available. + Details
Name: | mbwm_PercentageOfOutOfAreaInterestBearingChecking
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Out-of-area time, under $100,000. + References No definition available. + Details
Name: | mbwm_PercentageOfOutOfAreaTimeLessThan100000
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of time deposits, $100,000 and over. + References No definition available. + Details
Name: | mbwm_PercentageOfTimeDepositsEqualToGreaterThan100000
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of time deposits less than 100000. + References No definition available. + Details
Name: | mbwm_PercentageOfTimeDepositsLessThan100000
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage Out-of-area time, $100,000 and over. + References No definition available. + Details
Name: | mbwm_PercentageOutOfAreaTimeEqualToGreaterThan100000
Namespace Prefix: | mbwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-DEP -Paragraph 37, 38, 39 -IssueDate 2006-05-01 -Chapter 13 -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_Deposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of money in interest-bearing domestic accounts that entitle the depositor to withdraw funds at any time without prior notice, also known as demand deposits. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 9 + Details
Name: | us-gaap_InterestBearingDomesticDepositDemand
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of interest-bearing domestic money market demand account deposit liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 9 + Details
Name: | us-gaap_InterestBearingDomesticDepositMoneyMarket
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of interest-bearing domestic savings deposit liabilities. Saving deposits bear interest and have no stated maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 9 + Details
Name: | us-gaap_InterestBearingDomesticDepositSavings
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of money in noninterest-bearing domestic accounts that entitle the depositor to withdraw funds at any time without prior notice, also known as demand deposits. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 9 + Details
Name: | us-gaap_NoninterestBearingDomesticDepositDemand
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of interest-bearing domestic demand deposit liabilities to total deposit liabilities. + References No definition available. + Details
Name: | us-gaap_PercentageOfInterestBearingDomesticDepositsToDepositsDemand
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of interest-bearing domestic money market demand account deposit liabilities to total deposit liabilities. + References No definition available. + Details
Name: | us-gaap_PercentageOfInterestBearingDomesticDepositsToDepositsMoneyMarket
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of interest-bearing domestic savings deposit liabilities to total deposit liabilities. + References No definition available. + Details
Name: | us-gaap_PercentageOfInterestBearingDomesticDepositsToDepositsSavings
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The aggregate amount of domestic time deposits (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $100,000 or more. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 405 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6479006&loc=d3e64164-112818 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 01-6 -Paragraph 14 -Subparagraph e -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_TimeDeposits100000OrMoreDomestic
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The aggregate amount of domestic or foreign time deposits (including certificates of deposits, individual retirement accounts and open accounts) that total to less than $100,000. + References No definition available. + Details
Name: | us-gaap_TimeDepositsLessThan100000
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant