Premises, Furniture and Equipment (Details) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Premises, furniture and equipment, gross	$ 192,677,000	$ 170,345,000
Less accumulated depreciation	(64,383,000)	(60,139,000)
Premises, furniture and equipment, net	128,294,000	110,206,000
Depreciation expense	6,400,000	6,300,000	7,100,000
Land and Land Improvements
Property, Plant and Equipment [Line Items]
Premises, furniture and equipment, gross	35,114,000	33,092,000
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Premises, furniture and equipment, gross	106,891,000	92,125,000
Furniture and Equipment
Property, Plant and Equipment [Line Items]
Premises, furniture and equipment, gross	$ 50,672,000	$ 45,128,000

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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- Definition

Gross amount of long-lived 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, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived 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, furniture and fixtures, and computer equipment.

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