Premises and Equipment (Components of Premises and Equipment) (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Premises and equipment	$ 61,178	$ 60,863
Less accumulated depreciation	(24,315)	(22,153)
Total	36,863	38,710
Land [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	6,953	7,035
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	1,411	1,389
Premises [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	34,701	33,996
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment	$ 18,113	$ 18,443