XML 47 R34.htm IDEA: XBRL DOCUMENT
v3.19.2

Basis of Accounting and Consolidation Basis of Accounting and Consolidation (Stock Issuance) (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 6 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 15, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2018 | Aug. 16, 2017
Capital Raise [Abstract] |  |  |  |  |
Common stock, par value (in dollars per share) |  | $ 4 |  | $ 4 |
Proceeds from issuance of common stock |  | $ 334 | $ 36,263 |  |
Capital Raise [Member] |  |  |  |  |
Capital Raise [Abstract] |  |  |  |  |
shares underwriters agreed to purchase |  | 823,799 |  |  |
Shares Issued, Price Per Share | $ 38.00 |  |  |  |
Underwriters Option to Purchase Shares |  | 123,569 |  |  |
Shares, Issued | 947,368 |  |  |  |
Proceeds from issuance of common stock | $ 34,000 |  |  |  |
At The Market Program [Member] |  |  |  |  |
Balance of Common Stock Available Under ATM |  | $ 16,530 |  |  | $ 20,000

X
- Definition Value of common stock available under At-The-Market Program + References No definition available. + Details
Name: | fmbh_AvailableCommonStockUnderSalesAgencyAgreement
Namespace Prefix: | fmbh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Capital Raise [Abstract] + References No definition available. + Details
Name: | fmbh_CapitalRaiseAbstract
Namespace Prefix: | fmbh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Shares Underwriters Agreed to Purchase + References No definition available. + Details
Name: | fmbh_SharesUnderwritersAgreedtoPurchase
Namespace Prefix: | fmbh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Underwriters Option to Purchase Shares + References No definition available. + Details
Name: | fmbh_UnderwritersOptiontoPurchaseShares
Namespace Prefix: | fmbh_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face amount or stated value per share of common stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash inflow from the additional capital contribution to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
Name: | us-gaap_SharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Per share or per unit amount of equity securities issued. + References No definition available. + Details
Name: | us-gaap_SharesIssuedPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=fmbh_CapitalRaiseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=fmbh_AtTheMarketProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |