Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Basic
Net income	$ 1,331	$ 1,000	$ 3,691	$ 2,766
Dividends on non-vested restricted stock	(26)	(9)	(79)	(26)
Net income allocated to stockholders	$ 1,305	$ 991	$ 3,612	$ 2,740
Weighted average common shares outstanding	5,004,280	4,882,238	4,990,110	4,855,305
Basic earnings per common share	$ 0.26	$ 0.20	$ 0.72	$ 0.56
Diluted
Net income allocated to stockholders	$ 1,305	$ 991	$ 3,612	$ 2,740
Weighted average common shares outstanding for basic earnings per common share	5,004,280	4,882,238	4,990,110	4,855,305
Add: Dilutive effects of assumed exercise of stock options and restricted stock	172,975	127,093	225,449	128,093
Average shares and dilutive potential common shares	5,177,255	5,009,331	5,215,559	4,983,395
Diluted earnings per common share	$ 0.25	$ 0.20	$ 0.69	$ 0.55