Premises and Equipment (Composition of Premises and Equipment) (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Premises and equipment	$ 51,144	$ 50,503
Less accumulated depreciation	(25,946)	(24,874)
Premises and equipment, net	25,198	25,629
Land [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	7,304	7,304
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	1,210	1,210
Premises [Member]
Property, Plant and Equipment [Line Items]
Less accumulated depreciation	(25,272)	(25,112)
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	16,824	16,343
Capital Lease [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	$ 534	$ 534