XML 76 R61.htm IDEA: XBRL DOCUMENT v3.19.1
Bank Premises, Furniture, Fixtures and Equipment - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Property, Plant and Equipment [Abstract]      
Depreciation expense $ 936,632 $ 1,003,381 $ 980,514