Premises and Equipment (Details) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Premises and equipment
Premises and equipment, gross	$ 174,373,000	$ 158,832,000
Less: accumulated depreciation and amortization	131,350,000	119,459,000
Total	43,023,000	39,373,000
Depreciation and amortization expense	19,200,000	21,200,000	23,000,000
Furniture, fixtures and equipment
Premises and equipment
Premises and equipment, gross	141,497,000	127,904,000
Leasehold improvements
Premises and equipment
Premises and equipment, gross	$ 32,876,000	$ 30,928,000

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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Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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