CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Available-for-sale securities at fair value, amortized cost	$ 127,737	$ 113,828
Held-to-maturity securities at amortized cost, estimated fair value	26,348	26,271
Allowance for loan losses	6,463	6,128
Bank premises and equipment, accumulated depreciation	$ 5,727	$ 5,368
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	5,000,000	5,000,000
Common stock, par value	$ 1.00	$ 1.00
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	7,358,231	7,305,213
Common stock, shares outstanding	7,296,429	7,264,282