v2.4.0.6

Stock Incentive Plan Summary of Unvested Options (Details) (USD $) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Options, Nonvested, Number | 6,625 | 20,875 | 35,125 | 49,375
Options, Nonvested, Weighted Average Grant Date Fair Value | $ 2.51 | $ 3.16 | $ 3.29 | $ 3.34
Options, Vested in Period, Number | (14,250) | (14,250) | (14,250) |
Options, Vested in Period, Weighted Average Grant Date Fair Value | $ 3.47 | $ 3.47 | $ 3.47 |
Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options | $ 0 | $ 17,000 | $ 69,000 |

X
- Definition The number of non-vested stock options that validly exist and are outstanding as of the balance sheet date. + References No definition available. + Details
Name: | fmbh_OptionsNonvestedNumber
Namespace Prefix: | fmbh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The weighted average fair value of nonvested stock options that validly exist and are outstanding as of the balance sheet date. + References No definition available. + Details
Name: | fmbh_OptionsNonvestedWeightedAverageGrantDateFairValue
Namespace Prefix: | fmbh_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of stock options that vested during the reporting period. + References No definition available. + Details
Name: | fmbh_OptionsVestedInPeriodNumber
Namespace Prefix: | fmbh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted Average Grant Date Fair Value of stock options that vested during the period. + References No definition available. + Details
Name: | fmbh_OptionsVestedInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix: | fmbh_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate unrecognized cost of option awards made to employees under a stock option plan or plans, that have yet to vest. + References No definition available. + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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