XML 109 R99.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Regulatory Capital - Additional Information (Details) | 12 Months Ended
--- | ---
Dec. 31, 2024
Regulatory Capital [Abstract] |
Description of regulatory requirements, capital adequacy purposes | Quantitative measures established by each regulatory capital standards to ensure capital adequacy require the Company and its subsidiary bank to maintain a minimum capital amounts and ratios (set forth in the table below).

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

X
- Definition Description of the regulatory requirements for capital adequacy purposes. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477270/942-505-50-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477270/942-505-50-1H + Details
Name: | us-gaap_DescriptionOfRegulatoryRequirementsCapitalAdequacyPurposes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration