XML 57 R50.htm IDEA: XBRL DOCUMENT
v3.25.1

Loans and Allowance for Credit Losses - Credit Risk Profile of Loan Portfolio on Amortized Cost Basis Based on Risk Rating Category and Year of Origination (Details) - USD ($) $ in Thousands | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Credit Quality Information [Abstract] |  |
Current fiscal year | $ 338,407 | $ 862,051
Fiscal year before current fiscal year | 808,716 | 653,404
Two years before current fiscal year | 547,076 | 1,261,147
Three years before current fiscal year | 1,197,792 | 891,374
Four years before current fiscal year | 879,906 | 546,507
Prior | 1,846,541 | 1,377,588
Revolving Loans | 80,420 | 80,391
Current period gross write-offs, current fiscal year | 0 | 108
Current period gross write-offs, fiscal year before current fiscal year | 2 | 2,369
Current period gross write-offs, two year before current fiscal year | 568 | 625
Current period gross write-offs, three year before current fiscal year | 969 | 602
Current period gross write-offs, four year before current fiscal year | 110 | 69
Current period gross write-offs, prior | 434 | 1,975
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 5,698,858 | 5,672,462
Current period gross write-offs, total loans receivables | 2,083 | 5,748
Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 337,896 | 859,452
Fiscal year before current fiscal year | 799,976 | 626,738
Two years before current fiscal year | 514,430 | 1,245,490
Three years before current fiscal year | 1,183,133 | 885,295
Four years before current fiscal year | 870,847 | 542,310
Prior | 1,804,957 | 1,340,099
Revolving Loans | 79,716 | 79,714
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 5,590,955 | 5,579,098
Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 225 | 1,505
Fiscal year before current fiscal year | 7,366 | 17,281
Two years before current fiscal year | 25,602 | 6,668
Three years before current fiscal year | 6,966 | 4,213
Four years before current fiscal year | 7,075 | 3,488
Prior | 26,625 | 24,634
Revolving Loans | 160 | 59
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 74,019 | 57,848
Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 286 | 1,094
Fiscal year before current fiscal year | 1,374 | 9,385
Two years before current fiscal year | 7,044 | 8,989
Three years before current fiscal year | 7,693 | 1,866
Four years before current fiscal year | 1,984 | 709
Prior | 14,959 | 12,855
Revolving Loans | 544 | 618
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 33,884 | 35,516
Agricultural Loans |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 78,038 | 176,862
Fiscal year before current fiscal year | 150,022 | 33,324
Two years before current fiscal year | 27,422 | 16,332
Three years before current fiscal year | 23,108 | 9,262
Four years before current fiscal year | 14,350 | 1,585
Prior | 3,871 | 2,306
Revolving Loans | 0 | 0
Current period gross write-offs, current fiscal year | 0 | 0
Current period gross write-offs, fiscal year before current fiscal year | 0 | 2,213
Current period gross write-offs, two year before current fiscal year | 540 | 100
Current period gross write-offs, three year before current fiscal year | 503 | 52
Current period gross write-offs, four year before current fiscal year | 74 | 0
Current period gross write-offs, prior | 0 | 45
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 296,811 | 239,671
Current period gross write-offs, total loans receivables | 1,117 | 2,410
Agricultural Loans | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 77,868 | 175,402
Fiscal year before current fiscal year | 148,331 | 24,024
Two years before current fiscal year | 21,178 | 13,147
Three years before current fiscal year | 20,152 | 9,162
Four years before current fiscal year | 13,992 | 1,585
Prior | 3,871 | 2,306
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 285,392 | 225,626
Agricultural Loans | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 617
Fiscal year before current fiscal year | 590 | 2,208
Two years before current fiscal year | 2,214 | 976
Three years before current fiscal year | 793 | 100
Four years before current fiscal year | 80 | 0
Prior | 0 | 0
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 3,677 | 3,901
Agricultural Loans | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 170 | 843
Fiscal year before current fiscal year | 1,101 | 7,092
Two years before current fiscal year | 4,030 | 2,209
Three years before current fiscal year | 2,163 | 0
Four years before current fiscal year | 278 | 0
Prior | 0 | 0
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 7,742 | 10,144
Commercial Industrial And Other Portfolio Segment |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 135,036 | 307,904
Fiscal year before current fiscal year | 277,195 | 230,970
Two years before current fiscal year | 125,503 | 280,911
Three years before current fiscal year | 260,432 | 184,236
Four years before current fiscal year | 191,767 | 132,123
Prior | 479,351 | 369,008
Revolving Loans | 0 | 0
Current period gross write-offs, current fiscal year | 0 | 10
Current period gross write-offs, fiscal year before current fiscal year | 0 | 47
Current period gross write-offs, two year before current fiscal year | 14 | 207
Current period gross write-offs, three year before current fiscal year | 53 | 378
Current period gross write-offs, four year before current fiscal year | 0 | 10
Current period gross write-offs, prior | 156 | 36
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,469,284 | 1,505,152
Current period gross write-offs, total loans receivables | 223 | 688
Commercial Industrial And Other Portfolio Segment | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 135,026 | 307,785
Fiscal year before current fiscal year | 271,202 | 228,411
Two years before current fiscal year | 113,732 | 278,845
Three years before current fiscal year | 258,176 | 183,042
Four years before current fiscal year | 187,818 | 131,005
Prior | 469,240 | 360,610
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,435,194 | 1,489,698
Commercial Industrial And Other Portfolio Segment | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 10 | 54
Fiscal year before current fiscal year | 5,928 | 1,149
Two years before current fiscal year | 9,491 | 1,277
Three years before current fiscal year | 1,699 | 748
Four years before current fiscal year | 3,643 | 1,020
Prior | 7,516 | 7,583
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 28,287 | 11,831
Commercial Industrial And Other Portfolio Segment | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 65
Fiscal year before current fiscal year | 65 | 1,410
Two years before current fiscal year | 2,280 | 789
Three years before current fiscal year | 557 | 446
Four years before current fiscal year | 306 | 98
Prior | 2,595 | 815
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 5,803 | 3,623
Consumer Loans |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 1,498 | 5,110
Fiscal year before current fiscal year | 4,226 | 5,159
Two years before current fiscal year | 4,404 | 24,703
Three years before current fiscal year | 21,470 | 12,026
Four years before current fiscal year | 10,224 | 4,548
Prior | 5,398 | 2,414
Revolving Loans | 0 | 0
Current period gross write-offs, current fiscal year | 0 | 98
Current period gross write-offs, fiscal year before current fiscal year | 2 | 63
Current period gross write-offs, two year before current fiscal year | 14 | 154
Current period gross write-offs, three year before current fiscal year | 75 | 139
Current period gross write-offs, four year before current fiscal year | 36 | 59
Current period gross write-offs, prior | 239 | 1,491
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 47,220 | 53,960
Current period gross write-offs, total loans receivables | 366 | 2,004
Consumer Loans | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 1,498 | 5,098
Fiscal year before current fiscal year | 4,167 | 5,138
Two years before current fiscal year | 4,376 | 24,430
Three years before current fiscal year | 21,299 | 11,810
Four years before current fiscal year | 10,064 | 4,494
Prior | 5,331 | 2,385
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 46,735 | 53,355
Consumer Loans | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 20 | 0
Two years before current fiscal year | 0 | 14
Three years before current fiscal year | 36 | 0
Four years before current fiscal year | 0 | 0
Prior | 0 | 0
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 56 | 14
Consumer Loans | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 12
Fiscal year before current fiscal year | 39 | 21
Two years before current fiscal year | 28 | 259
Three years before current fiscal year | 135 | 216
Four years before current fiscal year | 160 | 54
Prior | 67 | 29
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 429 | 591
Real Estate Loan |  |
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 3,885,543 | 3,873,679
Real Estate Loan | Construction and Land Development |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 11,064 | 82,696
Fiscal year before current fiscal year | 99,298 | 101,715
Two years before current fiscal year | 108,605 | 14,396
Three years before current fiscal year | 14,452 | 15,817
Four years before current fiscal year | 15,111 | 4,735
Prior | 20,618 | 16,734
Revolving Loans | 0 | 0
Current period gross write-offs, current fiscal year | 0 | 0
Current period gross write-offs, fiscal year before current fiscal year | 0 | 0
Current period gross write-offs, two year before current fiscal year | 0 | 0
Current period gross write-offs, three year before current fiscal year | 0 | 0
Current period gross write-offs, four year before current fiscal year | 0 | 0
Current period gross write-offs, prior | 0 | 0
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 269,148 | 236,093
Current period gross write-offs, total loans receivables | 0 | 0
Real Estate Loan | Construction and Land Development | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 11,064 | 82,696
Fiscal year before current fiscal year | 99,298 | 101,715
Two years before current fiscal year | 108,605 | 14,390
Three years before current fiscal year | 14,446 | 15,817
Four years before current fiscal year | 15,111 | 4,735
Prior | 20,232 | 16,342
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 268,756 | 235,695
Real Estate Loan | Construction and Land Development | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 0 | 0
Two years before current fiscal year | 0 | 0
Three years before current fiscal year | 0 | 0
Four years before current fiscal year | 0 | 0
Prior | 377 | 382
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 377 | 382
Real Estate Loan | Construction and Land Development | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 0 | 0
Two years before current fiscal year | 0 | 6
Three years before current fiscal year | 6 | 0
Four years before current fiscal year | 0 | 0
Prior | 9 | 10
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 15 | 16
Real Estate Loan | Agricultural |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 17,676 | 25,824
Fiscal year before current fiscal year | 24,813 | 17,625
Two years before current fiscal year | 16,090 | 160,506
Three years before current fiscal year | 137,372 | 56,069
Four years before current fiscal year | 54,129 | 50,455
Prior | 123,333 | 80,281
Revolving Loans | 0 | 0
Current period gross write-offs, current fiscal year | 0 | 0
Current period gross write-offs, fiscal year before current fiscal year |  | 0
Current period gross write-offs, two year before current fiscal year | 0 | 0
Current period gross write-offs, three year before current fiscal year | 0 | 0
Current period gross write-offs, four year before current fiscal year | 0 | 0
Current period gross write-offs, prior | 0 | 0
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 373,413 | 390,760
Current period gross write-offs, total loans receivables | 0 | 0
Real Estate Loan | Agricultural | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 17,676 | 25,824
Fiscal year before current fiscal year | 24,813 | 17,292
Two years before current fiscal year | 15,902 | 159,433
Three years before current fiscal year | 136,691 | 55,083
Four years before current fiscal year | 53,147 | 48,700
Prior | 115,001 | 73,592
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 363,230 | 379,924
Real Estate Loan | Agricultural | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 0 | 192
Two years before current fiscal year | 188 | 107
Three years before current fiscal year | 107 | 986
Four years before current fiscal year | 982 | 1,755
Prior | 7,184 | 5,630
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 8,461 | 8,670
Real Estate Loan | Agricultural | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 0 | 141
Two years before current fiscal year | 0 | 966
Three years before current fiscal year | 574 | 0
Four years before current fiscal year | 0 | 0
Prior | 1,148 | 1,059
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,722 | 2,166
Real Estate Loan | Commercial And Multifamily Portfolio Segment |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 81,229 | 216,956
Fiscal year before current fiscal year | 213,245 | 227,485
Two years before current fiscal year | 229,384 | 688,599
Three years before current fiscal year | 669,498 | 537,576
Four years before current fiscal year | 519,346 | 290,568
Prior | 1,042,141 | 789,045
Revolving Loans | 0 | 0
Current period gross write-offs, current fiscal year | 0 | 0
Current period gross write-offs, fiscal year before current fiscal year | 0 | 0
Current period gross write-offs, two year before current fiscal year | 0 | 151
Current period gross write-offs, three year before current fiscal year | 338 | 0
Current period gross write-offs, four year before current fiscal year | 0 | 0
Current period gross write-offs, prior | 0 | 300
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 2,754,843 | 2,750,229
Current period gross write-offs, total loans receivables | 338 | 451
Real Estate Loan | Commercial And Multifamily Portfolio Segment | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 81,229 | 216,297
Fiscal year before current fiscal year | 212,592 | 213,704
Two years before current fiscal year | 215,627 | 680,665
Three years before current fiscal year | 662,091 | 535,056
Four years before current fiscal year | 516,834 | 289,855
Prior | 1,027,151 | 774,516
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 2,715,524 | 2,710,093
Real Estate Loan | Commercial And Multifamily Portfolio Segment | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 659
Fiscal year before current fiscal year | 653 | 13,732
Two years before current fiscal year | 13,709 | 4,090
Three years before current fiscal year | 4,052 | 2,053
Four years before current fiscal year | 2,055 | 713
Prior | 10,969 | 10,462
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 31,438 | 31,709
Real Estate Loan | Commercial And Multifamily Portfolio Segment | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 0 | 0
Fiscal year before current fiscal year | 0 | 49
Two years before current fiscal year | 48 | 3,844
Three years before current fiscal year | 3,355 | 467
Four years before current fiscal year | 457 | 0
Prior | 4,021 | 4,067
Revolving Loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 7,881 | 8,427
1-4 Family | Real Estate Loan |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 13,866 | 46,699
Fiscal year before current fiscal year | 39,917 | 37,126
Two years before current fiscal year | 35,668 | 75,700
Three years before current fiscal year | 71,460 | 76,388
Four years before current fiscal year | 74,979 | 62,493
Prior | 171,829 | 117,800
Revolving Loans | 80,420 | 80,391
Current period gross write-offs, current fiscal year | 0 | 0
Current period gross write-offs, fiscal year before current fiscal year | 0 | 46
Current period gross write-offs, two year before current fiscal year | 0 | 13
Current period gross write-offs, three year before current fiscal year | 0 | 33
Current period gross write-offs, four year before current fiscal year | 0 | 0
Current period gross write-offs, prior | 39 | 103
Current period gross write-offs, revolving loans | 0 | 0
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 488,139 | 496,597
Current period gross write-offs, total loans receivables | 39 | 195
1-4 Family | Real Estate Loan | Pass |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 13,535 | 46,350
Fiscal year before current fiscal year | 39,573 | 36,454
Two years before current fiscal year | 35,010 | 74,580
Three years before current fiscal year | 70,278 | 75,325
Four years before current fiscal year | 73,881 | 61,936
Prior | 164,131 | 110,348
Revolving Loans | 79,716 | 79,714
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 476,124 | 484,707
1-4 Family | Real Estate Loan | Special Mention |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 215 | 175
Fiscal year before current fiscal year | 175 | 0
Two years before current fiscal year | 0 | 204
Three years before current fiscal year | 279 | 326
Four years before current fiscal year | 315 | 0
Prior | 579 | 577
Revolving Loans | 160 | 59
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | 1,723 | 1,341
1-4 Family | Real Estate Loan | Substandard |  |
Credit Quality Information [Abstract] |  |
Current fiscal year | 116 | 174
Fiscal year before current fiscal year | 169 | 672
Two years before current fiscal year | 658 | 916
Three years before current fiscal year | 903 | 737
Four years before current fiscal year | 783 | 557
Prior | 7,119 | 6,875
Revolving Loans | 544 | 618
Loans Receivable Aging Analysis [Abstract] |  |
Total Loans Receivable | $ 10,292 | $ 10,549

X
- Definition Financing Receivable Current Period Gross Writeoffs Five Or More Years Before Latest Fiscal Year. + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsFiveOrMoreYearsBeforeLatestFiscalYear
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Current Period Gross Writeoffs Four Years Before Latest Fiscal Year. + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsFourYearsBeforeLatestFiscalYear
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Current Period Gross Writeoffs In Current Fiscal Year + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsInCurrentFiscalYear
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Current Period Gross Writeoffs In Fiscal Year Before Latest Fiscal Year. + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing receivable current period gross writeoffs including held for sale net of deferred income. + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsIncludingHeldForSaleNetOfDeferredIncome
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Current Period Gross Writeoffs Revolving. + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsRevolving
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Current Period Gross Writeoffs Three Years Before Latest Fiscal Year. + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsThreeYearsBeforeLatestFiscalYear
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Current Period Gross Writeoffs Two Years Before Latest Fiscal Year + References No definition available. + Details
Name: | fmbh_FinancingReceivableCurrentPeriodGrossWriteoffsTwoYearsBeforeLatestFiscalYear
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing receivable including held for sale net of deferred income. + References No definition available. + Details
Name: | fmbh_FinancingReceivableIncludingHeldForSaleNetOfDeferredIncome
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable, Recorded Investments, Aging. + References No definition available. + Details
Name: | fmbh_FinancingReceivableRecordedInvestmentsAgingAbstract
Namespace Prefix: | fmbh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Amortized cost of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated in current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable that can be withdrawn, repaid, and redrawn. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableRevolving
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fmbh_AgriculturalExcludingAgriculturalRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fmbh_CommercialIndustrialAndOtherPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fmbh_ConstructionAndLandDevelopmentPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fmbh_AgriculturalPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=fmbh_CommercialAndMultifamilyPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=fmbh_OneToFourFamilyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |