Premises and Equipment - Schedule of Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Land and improvements	$ 43,059	$ 32,665
Buildings and improvements	136,546	121,645
Furniture and equipment	72,050	71,959
Total cost	251,655	226,269
Accumulated depreciation and amortization	(118,358)	(114,066)
Total premises and equipment, net	$ 133,297	$ 112,203