Premises, Equipment and Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense for premises and equipment	$ 3,563	$ 4,135	$ 4,405
Impairment charges of long-term investments in land and buildings	364	259	935
Lease expense	784	$ 862	$ 1,060
Future minimum lease payments	$ 1