Parent Company Only Financial Statements - Schedule of Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net income	$ 6,820	$ 6,135	$ 2,496
Adjustments to reconcile net income to net cash provided by operating activities:
Issuance of vested restricted stock	90	90	90
Amortization of unearned compensation, net of forfeiture	250	214	126
(Increase) decrease in other assets	(4,731)	(1,065)	189
Increase in other liabilities	4,641	812	(122)
Net cash provided by operating activities	8,558	7,330	5,833
Cash Flows from Financing Activities
Repurchase of common stock	(21)	(8)	(7)
Cash dividends paid on common stock	(1,836)	(1,813)	(1,808)
Net cash provided by (used in) financing activities	(22,425)	79,714	16,975
Increase (decrease) in cash and cash equivalents	(20,769)	37,810	(38,546)
Cash and Cash Equivalents
Beginning	67,110	29,300	67,846
Ending	46,341	67,110	29,300
Fauquier Bankshares, Inc [Member]
Cash Flows from Operating Activities
Net income	6,820	6,135	2,496
Adjustments to reconcile net income to net cash provided by operating activities:
Undistributed earnings of subsidiaries	(4,745)	(4,883)	(1,116)
Issuance of vested restricted stock	90	90	90
Amortization of unearned compensation, net of forfeiture	153	133	79
(Increase) decrease in other assets	1	(33)	(8)
Increase in other liabilities	4	18	6
Net cash provided by operating activities	2,323	1,460	1,547
Cash Flows from Financing Activities
Repurchase of common stock	(21)	(8)	(7)
Cash dividends paid on common stock	(1,836)	(1,813)	(1,808)
Net cash provided by (used in) financing activities	(1,857)	(1,821)	(1,815)
Increase (decrease) in cash and cash equivalents	466	(361)	(268)
Cash and Cash Equivalents
Beginning	462	823	1,091
Ending	$ 928	$ 462	$ 823