Premises and Equipment - Summary of Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment, Net, by Type [Abstract]
Land & land improvements	$ 9,522	$ 8,909
Buildings	42,345	38,643
Furniture and equipment	31,428	31,081
Premises and equipment, gross	83,295	78,633
Less: Accumulated depreciation	(37,412)	(35,518)
Premises and equipment less depreciation, gross	45,883	43,115
Construction in progress	2,523	696
Total premises and equipment	$ 48,406	$ 43,811