Premises and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Amount paid under sale-leaseback arrangement	$ 202
Gain on sale of branch	$ 297
Sale-leaseback transaction	15 year
Total lease expense	$ 3,700	$ 2,900	$ 2,900
Premises and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation included in noninterest expense	$ 7,500	$ 7,200	$ 13,200