Business Segments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Total interest and dividend income	$ 9,178,000	$ 9,966,000	$ 27,280,000	$ 29,280,000
Service charges on deposits	302,000	460,000	888,000	1,263,000
Mortgage banking income, net	1,621,000	907,000	4,521,000	2,252,000
Title insurance income	543,000	434,000	1,386,000	1,116,000
Expenses
Interest expense	1,424,000	1,801,000	4,515,000	5,025,000
Provision for loan losses	1,000,000	3,750,000	3,300,000	6,800,000
Income tax expense (benefit)	(372,000)	(307,000)	(545,000)	(75,000)
Net income	2,206,000	(109,000)	6,127	2,841
Goodwill	2,884,000		2,884,000		$ 2,884,000
Total Assets	1,015,424,000		1,015,424,000		$ 813,999,000
TEB Life/FMFS
Total interest and dividend income	35,000	45,000	115,000	120,000
Service charges on deposits			0	0
Investment services and insurance income	176,000	172,000	543,000	497,000
Mortgage banking income, net			0	0
Title insurance income			0	0
Other operating income			0	0
Total income	211,000	217,000	658,000	617,000
Expenses
Interest expense			0	0
Provision for loan losses			0	0
Salary and benefit expense	73,000	71,000	231,000	221,000
Other operating expenses	16,000	18,000	42,000	46,000
Total expense	89,000	89,000	273	267,000
Income (loss) before taxes	122,000	128,000	385,000	350,000
Income tax expense (benefit)	(20,000)	(18,000)	(59,000)	(51,000)
Net income	102,000	110,000	326,000	299,000
Net income attributable to F & M Bank Corp.	102,000	110,000	326,000	299,000
Total Assets	7,911	7,617	7,911	7,617
Net (income) loss attributable to noncontrolling interest			0	0
F&M Bank Member
Total interest and dividend income	9,163,000	9,945,000	27,199,000	29,200,000
Service charges on deposits	302,000	460,000	888,000	1,263,000
Investment services and insurance income			0	2,000
Mortgage banking income, net			0	0
Title insurance income			0	0
Other operating income	572,000	678,000	1,668,000	1,786,000
Total income	10,037,000	11,083,000	29,775	32,251,000
Expenses
Interest expense	1,308,000	1,814,000	4,419,000	5,046,000
Provision for loan losses	1,000,000	3,750,000	3,300,000	6,800,000
Salary and benefit expense	3,257,000	3,581,000	9,623,000	10,156,000
Other operating expenses	2,899,000	2,825,000	8,622,000	8,317,000
Total expense	8,464,000	11,970,000	25,964,000	30,319,000
Income (loss) before taxes	1,573	(887,000)	3,791,000	1,932,000
Income tax expense (benefit)	(337)	(369,000)	(527,000)	(210,000)
Net income	1,236,000	(518,000)	3,264,000	2,142,000
Net income attributable to F & M Bank Corp.	1,236,000	(518,000)	3,264,000	2,142,000
Goodwill	2,670	2,670	2,670	2,670
Total Assets	(1,019,005)	816,130	(1,019,005)	816,130
Eliminations
Total interest and dividend income	(127,000)	(76,000)	(261,000)	(160,000)
Service charges on deposits			0	0
Investment services and insurance income	(9,000)	(7,000)	(18,000)	(12,000)
Mortgage banking income, net			0	0
Title insurance income			0	0
Other operating income			0	0
Total income	(136,000)	(83,000)	(279,000)	(172,000)
Expenses
Interest expense	127,000	76,000	41	160,000
Provision for loan losses			0	0
Salary and benefit expense			0	0
Other operating expenses	(9,000)	(7,000)	(4)	(12,000)
Total expense	136,000	83,000	45	172,000
Income (loss) before taxes			0	0
Income tax expense (benefit)			0	0
Net income			0	0
Net income attributable to F & M Bank Corp.			0	0
Total Assets	(146,378)	(116,100)	(146,378)	(116,100)
Net (income) loss attributable to noncontrolling interest			0	0
VS Title
Total interest and dividend income			0	0
Service charges on deposits			0	0
Investment services and insurance income			0	0
Mortgage banking income, net			0	0
Title insurance income	543,000	434,000	1,386,000	1,116,000
Other operating income			0	0
Total income	543,000	434,000	1,386,000	1,116,000
Expenses
Interest expense			0	0
Provision for loan losses			0	0
Salary and benefit expense	247,000	248,000	740,000	705,000
Other operating expenses	61,000	64,000	190,000	188,000
Total expense	308,000	312,000	930,000	893,000
Income (loss) before taxes	235,000	122,000	456,000	223,000
Income tax expense (benefit)			0	0
Net income	235,000	122,000	456,000	223,000
Net income attributable to F & M Bank Corp.	235,000	93,000	456,000	169,000
Goodwill	3		3
Total Assets	4,664	2,913	4,664	2,913
Net (income) loss attributable to noncontrolling interest		29,000		54,000
Parent Only
Total interest and dividend income			0	0
Service charges on deposits			0	0
Investment services and insurance income			0	0
Mortgage banking income, net			0	0
Title insurance income			0	0
Other operating income	(46,000)	(29,000)	(99,000)	(53,000)
Total income	(46,000)	(29,000)	(99,000)	(53,000)
Expenses
Interest expense	122,000		0	0
Provision for loan losses			122,000	0
Salary and benefit expense			0	0
Other operating expenses	17,000	9,000	32,000	40,000
Total expense	139,000	9,000	154,000	40,000
Income (loss) before taxes	(185,000)	(38,000)	(253,000)	(93,000)
Income tax expense (benefit)	(15,000)	(44,000)	(41,000)	(84,000)
Net income	(200,000)	(82,000)	(212,000)	(177,000)
Net income attributable to F & M Bank Corp.	(200,000)	(53,000)	(212,000)	(123,000)
Goodwill	164	164	164	164
Total Assets	105,633	90,390	105,633	90,390
Net (income) loss attributable to noncontrolling interest		(29,000)		(54,000)
F&M Bank Corp Consolidated
Total interest and dividend income	9,178,000	9,966,000	27,280,000	29,280,000
Service charges on deposits	302,000	460,000	888,000	1,263,000
Investment services and insurance income	167,000	165,000	525,000	487,000
Mortgage banking income, net	1,621,000	907,000	4,521,000	2,252,000
Title insurance income	543,000	434,000	1,386,000	1,116,000
Other operating income	595,000	679,000	1,695,000	1,791,000
Total income	12,406,000	12,611,000	36,295,000	36,189,000
Expenses
Interest expense	1,424,000	1,801,000	4,393,000	5,025,000
Provision for loan losses	1,000,000	3,750,000	3,422,000	6,800,000
Salary and benefit expense	4,081,000	4,391,000	12,249,000	12,492,000
Other operating expenses	3,223,000	3,085,000	9,559,000	9,106,000
Total expense	9,828,000	13,027,000	29,623,000	33,423,000
Income (loss) before taxes	2,578,000	(416,000)	6,672,000	2,766,000
Income tax expense (benefit)	(372,000)	(307,000)	(545,000)	(75,000)
Net income	2,206,000	(109,000)	6,127,000	2,841,000
Net income attributable to F & M Bank Corp.	2,206,000	(187,000)	6,022,000	2,735,000
Goodwill	2,884	2,884	2,884	2,884
Total Assets	1,015,424	813,237	1,015,424	813,237
Net (income) loss attributable to noncontrolling interest		78,000	105	106,000
F&M Mortgage
Total interest and dividend income	107,000	52,000	227,000	120,000
Service charges on deposits			0	0
Investment services and insurance income			0	0
Mortgage banking income, net	1,621,000	907,000	4,521,000	2,252,000
Title insurance income			0	0
Other operating income	69,000	30,000	126,000	58,000
Total income	1,797,000	989,000	4,874,000	2,430,000
Expenses
Interest expense	121,000	63,000	235,000	139,000
Provision for loan losses			0	0
Salary and benefit expense	504,000	491,000	1,665	1,410,000
Other operating expenses	339,000	176,000	691,000	527,000
Total expense	964,000	730,000	2,581,000	2,076,000
Income (loss) before taxes	833,000	259,000	2,293,000	354,000
Income tax expense (benefit)			0	0
Net income	833,000	259,000	2,293,000	354,000
Net income attributable to F & M Bank Corp.	833,000	181,000	2,188,000	248,000
Goodwill	47	47	47	47
Total Assets	$ 24,589	12,287	24,589	12,287
Net (income) loss attributable to noncontrolling interest		$ 78,000	$ 105,000	$ 106,000