Loans (Narrative) (Details) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($)	Sep. 30, 2022 USD ($) Loan Item	Dec. 31, 2021 USD ($) Item Loan	Sep. 30, 2021 USD ($)	Apr. 01, 2021 USD ($)
Loans And Leases Receivable Disclosure [Line Items]
Unamortized premium		$ 1,100	$ 1,100
Net deferred loan costs (fees)		(636)	(865)
Charged off		783	835
Fauquier Bankshares, Inc [Member]
Loans And Leases Receivable Disclosure [Line Items]
Loan receivable at fair value net			$ 611		$ 602,600
Purchased Impaired Loan [Member] | Fauquier Bankshares, Inc [Member]
Loans And Leases Receivable Disclosure [Line Items]
Loan receivable at fair value net		12,100			$ 23,100
Purchased Performing Loans [Member] | Fauquier Bankshares, Inc [Member]
Loans And Leases Receivable Disclosure [Line Items]
Loan receivable at fair value net		$ 5,000
Student Loans Purchased [Member]
Loans And Leases Receivable Disclosure [Line Items]
Extended period for repayment		12 months
Lifetime allowance period for military service		36 months
Grace period for repayment		6 months
Number of loans modified as TDRs | Item			5
Charged off			$ 56
Student Loans Purchased [Member] | Performing Loans [Member]
Loans And Leases Receivable Disclosure [Line Items]
Number of Loans classified as troubled debt restructuring | Item		48
Total Troubled Debt Restructurings		$ 756
1-4 family residential-purchased [Member]
Loans And Leases Receivable Disclosure [Line Items]
Number of secured loans | Loan		0	0
Paycheck Protection Program (PPP) Loans [Member]
Loans And Leases Receivable Disclosure [Line Items]
Bank funded loan amount outstanding		$ 254
COVID-19 [Member]
Loans And Leases Receivable Disclosure [Line Items]
Loan deferrals		$ 0	$ 1,200	$ 1,200
Small Business Administration [Member] | COVID-19 [Member] | Paycheck Protection Program (PPP) Loans [Member]
Loans And Leases Receivable Disclosure [Line Items]
Bank assisted nonprofit organizations and local businesses funded loans	$ 207,500