Premises and Equipment - Components of Premises and Equipment (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Total cost	$ 67,507	$ 63,754
Less: accumulated depreciation	(33,378)	(30,532)
Net book value	34,129	33,222
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Total cost	9,987	8,990
Premises and Improvements [Member]
Property, Plant and Equipment [Line Items]
Total cost	35,225	34,164
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Total cost	$ 22,295	$ 20,600