CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Stockholders Equity [Abstract]
Tax on change in unrealized loss on securities available for sale			$ 192
Tax on change in unrealized loss on investment securities	$ 897	$ (324)	(188)
Tax on change in unrecognized loss on securities held to maturity, portion of OTTI			4
Accretion on change in unrecognized loss on securities held to maturity, portion of OTTI			$ 8
Accretion in other comprehensive income on investment securities	$ 13	$ 16
Common stock dividends per share (in dollars per share)	$ 0.36	$ 0.32	$ 0.32
Issuance of common stock for warrants exercised (in shares)			49,500
Issuance of common shares under Stock Incentive Plan (in shares)	83,900	58,000	65,550
Issuance of common stock in connection with Eastern Virginia Bankshares, Inc. merger (in shares)			11,557,760