Completed Merger (Details) $ in Thousands	Apr. 01, 2019 USD ($) office office_consolidation shares	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	[1]	Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Total assets		$ 1,868,404	$ 1,862,866		$ 1,817,574
Subsequent Event
Business Acquisition [Line Items]
Number of office consolidations | office_consolidation	2
Subsequent Event | HomeTown Bankshares Corporation Merger
Business Acquisition [Line Items]
Total assets	$ 2,500,000
Number of shares issued per share of common stock (in shares) | shares	0.4150
Subsequent Event | Roanoke/New River Valley Markets | HomeTown Bankshares Corporation Merger
Business Acquisition [Line Items]
Number of offices after the merger | office	8

[1] Derived from audited consolidated financial statements.