Commitments, Changes in the Allowance for Unfunded Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2020
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period	$ 21,907
Cumulative effect of ASU 2016-13 adoption (CECL)	47,776	$ 21,907
Provision for credit losses	7,000
Balance at end of period	47,776	21,907
Change in the Allowance for Unfunded Commitments
Balance at beginning of period	21,907
Balance at end of period	47,776	21,907
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Cumulative effect of ASU 2016-13 adoption (CECL)			$ 40,597
First Staunton Bancshares
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Provision for credit losses	179
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Cumulative effect of ASU 2016-13 adoption (CECL)			$ 18,690
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member]
Change in the Allowance for Unfunded Commitments
Balance at beginning of period	21,907	24,336
Balance at beginning of period, adjusted		24,336
Provision for unfunded commitments	$ 7,000	(2,500)
Balance at end of period		21,907
Amount Recorded at Acquisition [Member] | SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member]
Change in the Allowance for Unfunded Commitments
Amount recorded at acquisition		$ 70