Goodwill and Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Feb. 29, 2012	Dec. 31, 2011
Goodwill [Roll Forward]
Balance, January 1, 2012	$ 0	$ 22,577
Acquired	22,577
Balance, June 30, 2012	22,577	22,577
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Net Carrying Amount	20,864		12,078
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2012	1,792
2013	6,430
2014	3,339
2015	2,361
2016	1,271
2017	1,178
Core deposit intangibles [Member]
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	55,420		43,446
Accumulated Amortization	36,273		31,368
Net Carrying Amount	19,147		12,078
Other [Member]
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	1,800		0
Accumulated Amortization	83		0
Net Carrying Amount	$ 1,717		$ 0

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Amount of amortization expense expected to be recognized in the next rolling twelve months following the latest balance sheet presented for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized in the remainder of the fiscal year following the latest fiscal year ended for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the fifth fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of amortization expense expected to be recognized during the second fiscal year following the latest fiscal year for assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation.

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