Name:	fmfg_LoansAndLeasesReceivableDueImmediately
Namespace Prefix:	fmfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans which due over five years.

No definition available.

Name:	fmfg_LoansAndLeasesReceivableDueOverFiveYears
Namespace Prefix:	fmfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans which due over one to five years.

No definition available.

Name:	fmfg_LoansAndLeasesReceivableDueOverOneToFiveYear
Namespace Prefix:	fmfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans which due within one year.

No definition available.

Name:	fmfg_LoansAndLeasesReceivableDueWithinOneYear
Namespace Prefix:	fmfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522