XML 86 R59.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Investment Securities, Part II (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2016 USD ($) securities | Dec. 31, 2016 USD ($) securities | Dec. 31, 2015 USD ($) securities | Dec. 31, 2014 USD ($)
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] |  |  |  |
One year or less | $ 82,570,000 | $ 82,570,000 |  |
After 1 through 5 years | 253,615,000 | 253,615,000 |  |
After 5 through 10 years | 281,080,000 | 281,080,000 |  |
After ten years | 2,583,000 | 2,583,000 |  |
Fair Value | 619,848,000 | $ 619,848,000 | $ 518,848,000 |
Available-for-sale, Weighted Average Yield, Maturities Year One (in hundredths) |  | 2.12% |  |
Available-for-sale , Weighted Average Yield, Maturities After 1 through 5 Years (in hundredths) |  | 2.36% |  |
Available-for-sale, Weighted Average Yield, Maturities After 5 through 10 Years (in hundredths) |  | 2.63% |  |
Available-for-sale , Weighted Average Yield, Maturities After 10 Years (in hundredths) |  | 2.20% |  |
Available-for-sale , Weighted Average Yield, Maturities (in hundredths) |  | 2.45% |  |
Available-for-sale, Full Tax-equivalent Yield, Maturities Year One (in hundredths) |  | 2.49% |  |
Available-for-sale, Full Tax-equivalent Yield, Maturities After 1 through 5 Years (in hundredths) |  | 2.93% |  |
Available-for-sale, Full Tax-equivalent Yield, Maturities After 5 through 10 years (in hundredths) |  | 3.07% |  |
Available-for-sale, Full Tax-equivalent Yield, Maturities After Ten Years (in hundredths) |  | 2.71% |  |
Available-for-sale, Full Tax-equivalent Yield, Maturities (in hundredths) |  | 2.93% |  |
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] |  |  |  |
Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount | 44,992,000 | $ 44,992,000 |  |
Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount | 29,239,000 | 29,239,000 |  |
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount | 0 | 0 |  |
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount | 0 | 0 |  |
Held-to-maturity, at amortized cost (estimated fair value of $73,096 at December 31, 2016 and $85,737 at December 31, 2015) | 74,231,000 | $ 74,231,000 | 85,208,000 |
Held To Maturity Weighted Average Yield Maturities Year One |  | 1.79% |  |
Held To Maturity Weighted Average Yield Maturities After 1 Through 5 Years |  | 2.08% |  |
Held To Maturity Weighted Average Yield Maturities After 5 Through 10 Years |  | 0.00% |  |
Held To Maturity Weighted Average Yield Maturities After 10 Years |  | 0.00% |  |
Held To Maturity Weighted Average Yield Maturities |  | 1.90% |  |
Held To Maturity Tax Equivalent Yield Maturities Year One |  | 1.79% |  |
Held To Maturity Tax Equivalent Yield Maturities After 1 Through 5 Years |  | 2.08% |  |
Held To Maturity Tax Equivalent Yield Maturities After 5 Through 10 Years |  | 0.00% |  |
Held To Maturity Tax Equivalent Yield Maturities After 10 Years |  | 0.00% |  |
Held To Maturity Tax Equivalent Yield Maturities |  | 1.90% |  |
Tax rate used to calculate tax-equivalent yields (in hundredths) |  | 35.00% |  |
Percentage investment book value exceeds total stockholders' equity (in hundredths) |  | 10.00% |  |
Investment Securities Pledged as Collateral | 509,296,000 | $ 509,296,000 | 404,000,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 484,981,000 | 484,981,000 | 204,325,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 9,411,000 | 9,411,000 | 1,049,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value | 9,525,000 | 9,525,000 | 35,867,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 1,673,000 | 1,673,000 | 1,984,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 494,506,000 | 494,506,000 | 240,192,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | $ 11,084,000 | 11,084,000 | 3,033,000 |
Details of Trust Preferred Securities [Abstract] |  |  |  |
Coupon Rate of Trust Preferred Security | floating rate coupon of 3-month LIBOR plus 90 basis points |  |  |
Number of Ratios Utilized in OTTI Credit Model | 29 |  |  |
OTTI Cash Flow Initial Default Rate | 2.00% |  |  |
Period For Initial Default Rate Used In OTTI Analysis | two years |  |  |
Default Rate Applied For Remainder Of OTTI Analysis | 36 basis points |  |  |
Recovery Rate Used In OTTI Cash Flow Analysis | 10.00% |  |  |
Credit losses on trust preferred securities held [Abstract] |  |  |  |
Beginning of period |  | 1,111,000 | 1,111,000 | $ 1,111,000
Additions related to OTTI losses not previously recognized |  | 0 | 0 | 0
Reductions due to sales / (recoveries) |  | 0 | 0 | 0
Reductions due to change in intent or likelihood of sale |  | 0 | 0 | 0
Additions related to increases in previously recognized OTTI losses |  | 0 | 0 | 0
Reductions due to increases in expected cash flows |  | 0 | 0 | 0
End of period | $ 1,111,000 | 1,111,000 | 1,111,000 | $ 1,111,000
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value | 43,798,000 | 43,798,000 |  |
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value | 29,298,000 | 29,298,000 |  |
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value | 0 | 0 |  |
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value | 0 | 0 |  |
Held-to-maturity Securities, Fair Value | 73,096,000 | 73,096,000 | 85,737,000 |
PreTSL XXVIII |  |  |  |
Details of Trust Preferred Securities [Abstract] |  |  |  |
Book Value | 3,050,000 | 3,050,000 |  |
Market Value | 1,652,000 | 1,652,000 |  |
Unrealized Gains (Losses) | (1,398,000) | (1,398,000) |  |
Other-than- temporary Impairment Recorded To-date |  | (1,111,000) |  |
U.S. Treasury securities and obligations of U.S. government corporations & agencies |  |  |  |
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] |  |  |  |
One year or less | 67,138,000 | 67,138,000 |  |
After 1 through 5 years | 42,647,000 | 42,647,000 |  |
After 5 through 10 years | 26,539,000 | 26,539,000 |  |
After ten years | 0 | 0 |  |
Fair Value | 136,324,000 | 136,324,000 | 90,141,000 |
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] |  |  |  |
Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount | 44,992,000 | 44,992,000 |  |
Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount | 29,239,000 | 29,239,000 |  |
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount | 0 | 0 |  |
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount | 0 | 0 |  |
Held-to-maturity, at amortized cost (estimated fair value of $73,096 at December 31, 2016 and $85,737 at December 31, 2015) | 74,231,000 | 74,231,000 | 85,208,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 125,257,000 | 125,257,000 | 34,942,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 2,508,000 | 2,508,000 | 142,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value | 0 | 0 | 12,971,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | 0 | 126,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 125,257,000 | 125,257,000 | 47,913,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | 2,508,000 | 2,508,000 | $ 268,000 |
Number of securities in Unrealized Loss Positions |  |  | 6 |
Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract] |  |  |  |
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 53,295,000 | 53,295,000 | $ 35,845,000 |
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (1,338,000) | (1,338,000) | (214,000) |
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 0 | 0 | 0 |
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | 0 | 0 |
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value | 53,295,000 | 53,295,000 | 35,845,000 |
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss | (1,338,000) | (1,338,000) | (214,000) |
Credit losses on trust preferred securities held [Abstract] |  |  |  |
Held-to-maturity Securities, Fair Value | 73,096,000 | 73,096,000 | 85,737,000 |
Obligations of states and political subdivisions |  |  |  |
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] |  |  |  |
One year or less | 14,860,000 | 14,860,000 |  |
After 1 through 5 years | 83,676,000 | 83,676,000 |  |
After 5 through 10 years | 63,382,000 | 63,382,000 |  |
After ten years | 787,000 | 787,000 |  |
Fair Value | 162,705,000 | 162,705,000 | 110,717,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 93,405,000 | 93,405,000 | 3,168,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 2,804,000 | 2,804,000 | 32,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value | 0 | 0 | 979,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | 0 | 23,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 93,405,000 | 93,405,000 | 4,147,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | 2,804,000 | 2,804,000 | $ 55,000 |
Number of securities in Unrealized Loss Positions | securities |  |  | 2 |
Mortgage-backed securities |  |  |  |
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] |  |  |  |
One year or less | 572,000 | 572,000 |  |
After 1 through 5 years | 125,297,000 | 125,297,000 |  |
After 5 through 10 years | 189,122,000 | 189,122,000 |  |
After ten years | 0 | 0 |  |
Fair Value | 314,991,000 | 314,991,000 | $ 312,054,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 266,319,000 | 266,319,000 | 164,249,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 4,099,000 | 4,099,000 | 841,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value | 5,878,000 | 5,878,000 | 20,011,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 270,000 | 270,000 | 611,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 272,197,000 | 272,197,000 | 184,260,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | $ 4,369,000 | $ 4,369,000 | $ 1,452,000 |
Number of securities in Unrealized Loss Positions | securities | 2 | 2 | 7 |
Trust preferred securities |  |  |  |
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] |  |  |  |
One year or less | $ 0 | $ 0 |  |
After 1 through 5 years | 0 | 0 |  |
After 5 through 10 years | 0 | 0 |  |
After ten years | 1,652,000 | 1,652,000 |  |
Fair Value | 1,652,000 | 1,652,000 | $ 1,906,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 0 | 0 | 0 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 0 | 0 | 0 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value | 1,652,000 | 1,652,000 | 1,906,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 1,398,000 | 1,398,000 | 1,224,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 1,652,000 | 1,652,000 | 1,906,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | $ 1,398,000 | $ 1,398,000 | $ 1,224,000 |
Number of securities in Unrealized Loss Positions | securities | 1 | 1 | 1 |
Other securities |  |  |  |
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] |  |  |  |
One year or less | $ 0 | $ 0 |  |
After 1 through 5 years | 1,995,000 | 1,995,000 |  |
After 5 through 10 years | 2,037,000 | 2,037,000 |  |
After ten years | 144,000 | 144,000 |  |
Fair Value | 4,176,000 | 4,176,000 | $ 4,030,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] |  |  |  |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value | 0 | 0 | 1,966,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 0 | 0 | 34,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value | 1,995,000 | 1,995,000 | 0 |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 5,000 | 5,000 | 0 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 1,995,000 | 1,995,000 | 1,966,000 |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | $ 5,000 | $ 5,000 | $ 34,000 |

X
- Definition The yield on an available-for-sale government security, when the effect of reduced taxes are taken into account, for securities that mature. The full tax-equivalent yield show what yield a fully taxable security would have to give, in order to be equivalent to a tax free government security. + References No definition available. + Details
Name: | fmbh_AvailableForSaleFullTaxEquivalentYieldMaturities
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The yield on an available-for-sale government security, when the effect of reduced taxes are taken into account, for securities that mature after one through five years. The full tax-equivalent yield show what yield a fully taxable security would have to give, in order to be equivalent to a tax free government security. + References No definition available. + Details
Name: | fmbh_AvailableForSaleFullTaxEquivalentYieldMaturitiesAfter1Through5Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The yield on an available-for-sale government security, when the effect of reduced taxes are taken into account, for securities that mature after five through ten years. The full tax-equivalent yield show what yield a fully taxable security would have to give, in order to be equivalent to a tax free government security. + References No definition available. + Details
Name: | fmbh_AvailableForSaleFullTaxEquivalentYieldMaturitiesAfter5Through10Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The yield on an available for sale government security, when the effect of reduced taxes are taken into account, for securities that mature after ten years. The full tax-equivalent yield show what yield a fully taxable security would have to give, in order to be equivalent to a tax free government security. + References No definition available. + Details
Name: | fmbh_AvailableForSaleFullTaxEquivalentYieldMaturitiesAfterTenYears
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The yield on an available-for-sale government security, when the effect of reduced taxes are taken into account, for securities that mature in less than twelve months. The full tax-equivalent yield show what yield a fully taxable security would have to give, in order to be equivalent to a tax free government security. + References No definition available. + Details
Name: | fmbh_AvailableForSaleFullTaxEquivalentYieldMaturitiesYearOne
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average yield for available-for-sale investment securities held by the entity with maturities. + References No definition available. + Details
Name: | fmbh_AvailableForSaleWeightedAverageYieldMaturities
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average yield for available-for-sale investment securities held by the entity with maturities after ten years. + References No definition available. + Details
Name: | fmbh_AvailableForSaleWeightedAverageYieldMaturitiesAfter10Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average yield for available-for-sale investment securities held by the entity with maturities after one through five years. + References No definition available. + Details
Name: | fmbh_AvailableForSaleWeightedAverageYieldMaturitiesAfter1Through5Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average yield for available-for-sale investment securities held by the entity with maturities after five through ten years. + References No definition available. + Details
Name: | fmbh_AvailableForSaleWeightedAverageYieldMaturitiesAfter5Through10Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average yield for available-for-sale investment securities held by the entity with maturities of one year or less. + References No definition available. + Details
Name: | fmbh_AvailableForSaleWeightedAverageYieldMaturitiesYearOne
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Coupon Rate of Trust Preferred Security + References No definition available. + Details
Name: | fmbh_CouponRateofTrustPreferredSecurity
Namespace Prefix: | fmbh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | fmbh_CreditLossesOnTrustPreferredSecuritiesHeldAbstract
Namespace Prefix: | fmbh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Default Rate Applied For Remainder Of OTTI Analysis Following Initial Two Year Period + References No definition available. + Details
Name: | fmbh_DefaultRateAppliedForRemainderOfOTTIAnalysis
Namespace Prefix: | fmbh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | fmbh_DetailsOfTrustPreferredSecuritiesAbstract
Namespace Prefix: | fmbh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Tax Equivalent Yield Maturities + References No definition available. + Details
Name: | fmbh_HeldToMaturityTaxEquivalentYieldMaturities
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Tax Equivalent Yield Maturities After 10 Years + References No definition available. + Details
Name: | fmbh_HeldToMaturityTaxEquivalentYieldMaturitiesAfter10Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Tax Equivalent Yield Maturities After 1 Through 5 Years + References No definition available. + Details
Name: | fmbh_HeldToMaturityTaxEquivalentYieldMaturitiesAfter1Through5Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Tax Equivalent Yield Maturities After 5 Through 10 Years + References No definition available. + Details
Name: | fmbh_HeldToMaturityTaxEquivalentYieldMaturitiesAfter5Through10Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Tax Equivalent Yield Maturities Year One + References No definition available. + Details
Name: | fmbh_HeldToMaturityTaxEquivalentYieldMaturitiesYearOne
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Weighted Average Yield Maturities + References No definition available. + Details
Name: | fmbh_HeldToMaturityWeightedAverageYieldMaturities
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Weighted Average Yield Maturities After 10 Years + References No definition available. + Details
Name: | fmbh_HeldToMaturityWeightedAverageYieldMaturitiesAfter10Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Weighted Average Yield Maturities After 1 Through 5 Years + References No definition available. + Details
Name: | fmbh_HeldToMaturityWeightedAverageYieldMaturitiesAfter1Through5Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Weighted Average Yield Maturities After 5 Through 10 Years + References No definition available. + Details
Name: | fmbh_HeldToMaturityWeightedAverageYieldMaturitiesAfter5Through10Years
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Held To Maturity Weighted Average Yield Maturities Year One + References No definition available. + Details
Name: | fmbh_HeldToMaturityWeightedAverageYieldMaturitiesYearOne
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Ratios Utilized in OTTI Evaluation Credit Model developed by Third Party + References No definition available. + Details
Name: | fmbh_NumberofRatiosUtilizedinOTTICreditModel
Namespace Prefix: | fmbh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition OTTI Cash Flow Default Rate used for first two years of analysis + References No definition available. + Details
Name: | fmbh_OTTICashFlowInitialDefaultRate
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage investment book value exceeds total stockholders' equity. + References No definition available. + Details
Name: | fmbh_PercentageInvestmentBookValueExceedsTotalStockholdersEquity
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Years Initial Default Rate Is Applied In OTTI Analysis + References No definition available. + Details
Name: | fmbh_PeriodForInitialDefaultRateUsedInOTTIAnalysis
Namespace Prefix: | fmbh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Recovery Rate Used In OTTI Cash Flow Analysis + References No definition available. + Details
Name: | fmbh_RecoveryRateUsedInOTTICashFlowAnalysis
Namespace Prefix: | fmbh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition This item represents the book value cost of trust preferred securities. + References No definition available. + Details
Name: | fmbh_TrustPreferredSecuritiesBookValue
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the market value cost of trust preferred securities. + References No definition available. + Details
Name: | fmbh_TrustPreferredSecuritiesMarketValue
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of other than temporary impairment losses on trust preferred securities which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis. + References No definition available. + Details
Name: | fmbh_TrustPreferredSecuritiesOtherThanTemporaryImpairmentLossRecognizedInEarnings
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the excess of amortized cost basis over fair value of preferred trust securities in a loss position. + References No definition available. + Details
Name: | fmbh_TrustPreferredSecuritiesUnrealizedLossPosition
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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 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
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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
- Definition Fair value of available-for-sale debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27198-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of available-for-sale debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of available-for-sale debt securities maturing after the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27198-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investments in debt securities classified as available-for-sale, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer. + 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=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26626-111562 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value of available-for-sale securities that serve as collateral for borrowings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5086-111524 + Details
Name: | us-gaap_AvailableForSaleSecuritiesPledgedAsCollateral
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement. + 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 (b)(3) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
Name: | us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32687-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 6.I) -URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=65882285&loc=d3e32698-109319 + Details
Name: | us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.6) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_HeldToMaturitySecurities
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 securities classified as held-to-maturity 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 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_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity 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_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the fair value of securities categorized as held-to-maturity which are in an unrealized 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 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
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 securities classified as held-to-maturity 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 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_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the fair value of securities categorized as held-to-maturity 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 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_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the fair value of securities categorized as held-to-maturity 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 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_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of held-to-maturity debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(3) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, maturing in the fifth through tenth fiscal year following the latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(3) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of held-to-maturity debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, maturing in the next fiscal year through the fifth fiscal year following the latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of held-to-maturity debt securities maturing after the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(4) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, maturing after the tenth fiscal year following the latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(4) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesNetCarryingAmountAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of held-to-maturity debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount of debt securities accounted for as held-to-maturity, net of adjustments including, but not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized, and fair value hedge accounting adjustments, maturing in the next fiscal year following the latest fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62586-112803 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which a previous OTTI was recognized and the investor does not intend to sell the debt security and it is not more likely than not that the investor will be required to sell the debt security before recovery of its amortized cost basis. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsAdditionalCreditLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which no such other than temporary impairment (OTTI) was previously recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsAdditionsNoPreviousImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsCreditLossesOnDebtSecuritiesHeld
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held due to increases in cash flows expected to be collected and recognized over the remaining life of the security. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsCashFlows
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents reductions in the amount of cumulative losses recognized in earnings for other than temporary impairments (OTTI) for which a portion of the impairment had been recognized in other comprehensive income (a component of shareholders' equity) due to a change in status of the impaired security because of a change in the entity's intent to either sell the impaired security or it has become more likely than not that the entity will be required to sell the security before recovery of its cost basis. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsChangeInStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security because of the sale of impaired securities during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=73527792&loc=SL6284393-111563 + Details
Name: | us-gaap_OtherThanTemporaryImpairmentCreditLossesRecognizedInEarningsReductionsSecuritiesSold
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_DebtSecurityAxis=fmbh_PretslXxviiiMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_TrustPreferredSecuritiesSubjectToMandatoryRedemptionMember
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: |