Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands		1 Months Ended			3 Months Ended		9 Months Ended
		Apr. 30, 2019	Jan. 31, 2015	Jul. 31, 2011	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Goodwill
Beginning balance	[1]						$ 43,872
Additions							40,761
Amortization							0
Impairment							0
Ending balance					$ 84,633	$ 43,872	84,633	$ 43,872
Intangibles
Beginning balance							926
Additions							8,200
Amortization					(448)	$ (56)	(961)	$ (210)
Impairment							0
Ending balance					$ 8,165		$ 8,165
MidCarolina
Acquired Finite-Lived Intangible Assets [Line Items]
Core deposit intangible				$ 6,556
Amortization period of intangible				108 months
MainStreet BankShares, Inc.
Acquired Finite-Lived Intangible Assets [Line Items]
Core deposit intangible			$ 1,839
Amortization period of intangible			120 months
HomeTown Bankshares Corporation
Acquired Finite-Lived Intangible Assets [Line Items]
Core deposit intangible		$ 8,200
Amortization period of intangible		120 months

[1] Derived from audited consolidated financial statements.