Proposed Merger (Details) $ in Thousands		3 Months Ended
	Oct. 01, 2018 USD ($) office office_consolidation shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Number of office consolidations | office_consolidation	2
Total assets		$ 1,862,866	$ 1,816,078	$ 1,678,638
HomeTown Bankshares Corporation Merger
Business Acquisition [Line Items]
Merger transaction, value		$ 95,600
Total assets	$ 2,400,000
Number of shares issued per share of common stock (in shares) | shares	0.4150
Roanoke/New River Valley Markets | HomeTown Bankshares Corporation Merger
Business Acquisition [Line Items]
Number of offices after the merger | office	8