CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Investment securities held to maturity	$ 5,983	$ 6,391
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	35,000,000	35,000,000
Common Stock, shares, issued	12,748,273	12,688,224
Common stock, shares outstanding	12,748,273	12,688,224
Common stock, unvested restricted shares		15,913