Parent Company Only Financial Statements - Schedule of Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income
Interest income	$ 26,398	$ 24,291	$ 21,147
Total interest income	29,170	26,698	23,320
Expenses
Interest expense	4,520	3,233	2,049
Directors' fees	326	329	322
Miscellaneous	3,427	3,414	3,187
Total noninterest expenses	22,454	22,151	20,844
Income before income taxes	7,824	6,881	5,375
Income tax benefit	1,004	746	2,879
Net Income	6,820	6,135	2,496
Fauquier Bankshares, Inc [Member]
Income
Interest income	9	4	4
Dividends from subsidiaries	2,654	1,813	1,808
Total interest income	2,663	1,817	1,812
Expenses
Interest expense	199	199	199
Legal and professional fees	184	149	105
Directors' fees	218	218	212
Miscellaneous	285	288	145
Total noninterest expenses	886	854	661
Income before income taxes	1,777	963	1,151
Income tax benefit	(298)	(289)	(229)
Income before equity in undistributed net income of subsidiaries	2,075	1,252	1,380
Equity in undistributed net income of subsidiaries	4,745	4,883	1,116
Net Income	$ 6,820	$ 6,135	$ 2,496