Premises and Equipment - Major Categories of Banking Premises and Equipment and Accumulated Depreciation (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Premises and Equipment (Gross)	$ 58,022	$ 57,841
Less: Accumulated depreciation	(30,959)	(31,558)
Premises and Equipment (Net)	27,063	26,283
Land [Member]
Property, Plant and Equipment [Line Items]
Premises and Equipment (Gross)	6,951	6,951
Buildings [Member]
Property, Plant and Equipment [Line Items]
Premises and Equipment (Gross)	30,124	28,845
Furnishings [Member]
Property, Plant and Equipment [Line Items]
Premises and Equipment (Gross)	$ 20,947	$ 22,045

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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