Earnings per Common Share - Computation of Basic and Diluted Earnings per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic
Net income	$ 3,122	$ 2,240	$ 6,292	$ 4,951
Preferred stock dividends	391	406	795	1,061
Net income available to common shareholders - basic	$ 2,731	$ 1,834	$ 5,497	$ 3,890
Weighted average common shares outstanding - basic	7,825,176	7,707,917	7,790,862	7,707,917
Basic earnings per common share	$ 0.35	$ 0.24	$ 0.71	$ 0.50
Diluted
Net income available to common shareholders - basic	$ 2,731	$ 1,834	$ 5,497	$ 3,890
Preferred stock dividends on convertible preferred stock	391	406	795	1,061
Net income available to common shareholders - diluted	$ 3,122	$ 2,240	$ 6,292	$ 4,951
Weighted average common shares outstanding for basic earnings per common share basic	7,825,176	7,707,917	7,790,862	7,707,917
Add: Dilutive effects of convertible preferred shares	3,079,665	3,196,931	3,113,980	3,196,931
Add: Dilutive effects of unearned restricted stock	92
Average shares and dilutive potential common shares outstanding - diluted	10,904,933	10,904,848	10,904,842	10,904,848
Diluted earnings per common share	$ 0.29	$ 0.21	$ 0.58	$ 0.43