Premises and Equipment (Detail) - Schedule of Premises and Equipment by Major Category (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2011
Premises and Equipment	$ 131,264	$ 128,223	$ 127,435
Less: accumulated depreciation and amortization
Accumulated Depreciation and Amortization	(45,886)	(45,316)	(44,012)
Net premises and equipment	85,378	82,907	83,423
Land [Member]
Premises and Equipment	31,757	29,902	29,833
Building [Member]
Premises and Equipment	59,051	57,482	57,227
Less: accumulated depreciation and amortization
Accumulated Depreciation and Amortization	(19,712)	(18,557)	(18,090)
Furniture and Fixtures [Member]
Premises and Equipment	29,732	29,828	29,423
Less: accumulated depreciation and amortization
Accumulated Depreciation and Amortization	(20,382)	(21,212)	(20,576)
Leasehold Improvements [Member]
Premises and Equipment	10,724	11,011	10,952
Less: accumulated depreciation and amortization
Accumulated Depreciation and Amortization	$ (5,792)	$ (5,547)	$ (5,346)

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 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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