Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands		1 Months Ended		3 Months Ended
		Jan. 31, 2015	Jul. 31, 2011	Mar. 31, 2019	Mar. 31, 2018
Goodwill
Beginning Balance	[1]			$ 43,872
Additions				0
Amortization				0
Impairment				0
Ending Balance				43,872	$ 43,872
Intangibles
Beginning Balance				926
Additions				0
Amortization				(55)	$ (77)
Impairment				0
Ending Balance				$ 871
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

[1] Derived from audited consolidated financial statements.