XML 106 R84.htm IDEA: XBRL DOCUMENT v3.8.0.1
Premises and Equipment - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Property Plant And Equipment [Abstract]      
Depreciation $ 1,249 $ 1,257 $ 1,193
Rent expense $ 580 $ 540 $ 506