Business Segments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Interest Income	$ 7,966,000	$ 7,754,000	$ 23,394,000	$ 22,765,000
Service charges on deposits	300,000	302,000	839,000	888,000
Mortgage banking income, net	1,176,000	1,621,000	3,874,000	4,521,000
Title insurance income	556,000	543,000	1,607,000	1,386,000
Interest expense	1,089,000	1,424,000	3,226,000	4,515,000
Income tax expense (benefit)	319,000	372,000	1,012,000	545,000
Net income (loss)	2,337,000	2,206,000	9,358,000	6,127,000
Total Assets	1,170,659,000		1,170,659,000		$ 966,930,000
Goodwill	3,082,000		3,082,000		$ 2,884,000
F&M Bank Member
Interest Income	9,010,000	9,163,000	26,499,000	27,199,000
Service charges on deposits	300,000	302,000	839,000	888,000
Investment services and insurance income	0	0	0	0
Mortgage banking income, net	0	0	0	0
Title insurance income	0	0	0	0
Other operating income	711,000	572,000	2,334,000	1,668,000
Total income	10,021,000	10,037,000	29,672,000	29,755,000
Interest expense	919,000	1,308,000	2,690,000	4,419,000
Provision for loan losses	(235,000)	(1,000,000)	(2,210,000)	(3,300,000)
Salary and benefit expense	3,660,000	3,257,000	10,772,000	9,623,000
Other operating expenses	3,477,000	2,899,000	9,777,000	8,622,000
Total expense	7,821,000	8,464,000	21,029,000	25,964,000
Income (loss) before taxes	2,200,000	1,573,000	8,643,000	3,791,000
Income tax expense (benefit)	277,000	337,000	1,199,000	527,000
Net income (loss)		1,236,000		3,264,000
Net (income) loss attributable to noncontrolling interest		1,236,000		0
Net Income attributable to F & M Bank Corp	1,923,000	9,163,000	7,444,000	3,264,000
Total Assets	10,255,000	1,019,005,000	10,255,000	1,019,005,000
Goodwill	47,000	2,670,000	47,000	2,670,000
F&M Mortgage
Interest Income	41,000		165,000
Service charges on deposits	0		0
Investment services and insurance income	0		0
Mortgage banking income, net	1,176,000		3,874,000
Title insurance income	0		0
Other operating income	41,000		121,000
Total income	1,258,000		4,160,000
Interest expense	17,000		115,000
Provision for loan losses	0		0
Salary and benefit expense	620,000		1,902,000
Other operating expenses	213,000		677,000
Total expense	850,000		2,694,000
Income (loss) before taxes	408,000		1,466,000
Income tax expense (benefit)	0		0
Net Income attributable to F & M Bank Corp	408,000		1,466,000
Total Assets	10,255,000		10,255,000
Goodwill	47,000		47,000
TEB Life/FMFS
Interest Income	26,000	35,000	85,000	115,000
Service charges on deposits	0	0	0	0
Investment services and insurance income	213,000	176,000	742,000	543,000
Mortgage banking income, net	0	0	0	0
Title insurance income	0	0	0	0
Other operating income	0	0	0	0
Total income	239,000	211,000	827,000	658,000
Interest expense	0	0	0	0
Provision for loan losses	0	0	0	0
Salary and benefit expense	99,000	73,000	280,000	231,000
Other operating expenses	18,000	16,000	37,000	42,000
Total expense	117,000	89,000	317,000	273,000
Income (loss) before taxes	122,000	122,000	510,000	385,000
Income tax expense (benefit)	26,000	20,000	107,000	59,000
Net income (loss)		102,000		326,000
Net (income) loss attributable to noncontrolling interest		102,000		0
Net Income attributable to F & M Bank Corp	96,000	35,000	403,000	326,000
Total Assets	8,434,000	7,911,000	8,434,000	7,911,000
Goodwill	0	0	0	0
VS Title
Interest Income	0	0	0	0
Service charges on deposits	0	0	0	0
Investment services and insurance income	0	0	0	0
Mortgage banking income, net	0	0	0	0
Title insurance income	556,000	543,000	1,607,000	1,386,000
Other operating income	0	0	0	0
Total income	556,000	543,000	16,000	1,386,000
Interest expense	0	0	0	0
Provision for loan losses	0	0	0	0
Salary and benefit expense	323,000	247,000	905,000	740,000
Other operating expenses	73,000	61,000	227,000	190,000
Total expense	396,000	308,000	11,320,000	930,000
Income (loss) before taxes	160,000	235,000	475,000	456,000
Income tax expense (benefit)	0	0	0	0
Net income (loss)		235,000		456,000
Net (income) loss attributable to noncontrolling interest		235,000		0
Net Income attributable to F & M Bank Corp	160,000	0	475,000	456,000
Total Assets	2,802,000	4,664,000	2,802,000	4,664,000
Goodwill	3,000	3,000	3,000	3,000
Parent Only
Interest Income	1,000	0	1,000	0
Service charges on deposits	0	0	0	0
Investment services and insurance income	0	0	0	0
Mortgage banking income, net	0	0	0	0
Title insurance income	0	0	0	0
Other operating income	38,000	46,000	114,000	99,000
Total income	(38,000)	(46,000)	(113,000)	(99,000)
Interest expense	175,000	122,000	551,000	0
Provision for loan losses	0	0	0	(122,000)
Salary and benefit expense	0	0	0	0
Other operating expenses	21,000	17,000	60,000	32,000
Total expense	196,000	139,000	611,000	154,000
Income (loss) before taxes	(234,000)	(185,000)	(724,000)	(253,000)
Income tax expense (benefit)	16,000	15,000	(294,000)	(41,000)
Net income (loss)		(200,000)		(212,000)
Net (income) loss attributable to noncontrolling interest		(200,000)		0
Net Income attributable to F & M Bank Corp	(250,000)	0	430,000	(212,000)
Total Assets	113,627,000	105,633,000	113,627,000	105,633,000
Goodwill	164,000	164,000	164,000	164,000
Eliminations
Interest Income	(22,000)	(127,000)	(130,000)	(261,000)
Service charges on deposits	0	0	0	0
Investment services and insurance income	(3,000)	(9,000)	(6,000)	(18,000)
Mortgage banking income, net	0	0	0	0
Title insurance income	0	0	0	0
Other operating income	0	0	0	0
Total income	(25,000)	(136,000)	(136,000)	(279,000)
Interest expense	22,000	127,000	130,000	261,000
Provision for loan losses	0	0	0	0
Salary and benefit expense	0	0	0	0
Other operating expenses	(3,000)	(9,000)	(6,000)	(18,000)
Total expense	25,000	136,000	136,000	279,000
Income (loss) before taxes	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Net income (loss)		0		0
Net (income) loss attributable to noncontrolling interest		0		0
Net Income attributable to F & M Bank Corp	0	(127,000)	0	0
Total Assets	(14,072,000)	(146,378,000)	(14,072,000)	(146,378,000)
Goodwill	0	0	0	0
F&M Bank Corp Consolidated
Interest Income	9,055,000	9,178,000	26,620,000	27,280,000
Service charges on deposits	300,000	302,000	839,000	888,000
Investment services and insurance income	210,000	167,000	736,000	525,000
Mortgage banking income, net	1,176,000	1,621,000	3,874,000	4,521,000
Title insurance income	556,000	543,000	1,607,000	1,386,000
Other operating income	714,000	595,000	2,341,000	1,695,000
Total income	12,011,000	12,406,000	36,017,000	36,295,000
Interest expense	1,089,000	1,424,000	3,226,000	4,393,000
Provision for loan losses	(235,000)	(1,000,000)	(2,210,000)	(3,422,000)
Salary and benefit expense	4,702,000	4,081,000	13,859,000	12,249,000
Other operating expenses	3,799,000	3,223,000	10,772,000	9,559,000
Total expense	9,355,000	9,828,000	25,647,000	29,623,000
Income (loss) before taxes	2,656,000	2,578,000	10,370,000	6,672,000
Income tax expense (benefit)	319,000	372,000	1,012,000	545,000
Net income (loss)		2,206,000		6,127,000
Net (income) loss attributable to noncontrolling interest		2,206,000		105,000
Net Income attributable to F & M Bank Corp	2,337,000	9,178,000	9,358,000	6,022,000
Total Assets	1,170,659,000	1,015,424,000	1,170,659,000	1,015,424,000
Goodwill	$ 3,082,000	2,884,000	$ 3,082,000	2,884,000
VBS Mortgage
Interest Income		107,000		227,000
Service charges on deposits		0		0
Investment services and insurance income		0		0
Mortgage banking income, net		1,621,000		4,521,000
Title insurance income		0		0
Other operating income		69,000		126,000
Total income		1,797,000		4,874,000
Interest expense		121,000		235,000
Provision for loan losses		0		0
Salary and benefit expense		504,000		1,655,000
Other operating expenses		339,000		691,000
Total expense		964,000		2,581,000
Income (loss) before taxes		833,000		2,293,000
Income tax expense (benefit)		0		0
Net income (loss)		833,000		2,293,000
Net (income) loss attributable to noncontrolling interest		833,000		105,000
Net Income attributable to F & M Bank Corp		107,000		2,188,000
Total Assets		24,589,000		24,589,000
Goodwill		$ 47,000		$ 47,000