Summary of Significant Accounting Policies - Reconciliation of Components of Basic and Diluted Earnings Per Share (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Earnings Per Share Reconciliation [Abstract]      
Net earnings available to common shareholders $ 5,403 $ 4,006 $ 2,057
Weighted average common shares outstanding 5,888,862 5,730,114 5,730,114
Dilutive effect of stock options 19,266 6,511 3,276
Dilutive effect of performance share awards 52,071 27,660 7,010
Diluted common shares 5,960,199 5,764,285 5,740,400
Basic earnings per common share $ 0.92 $ 0.70 $ 0.36
Diluted earnings per common share $ 0.91 $ 0.69 $ 0.36