Goodwill, Core Deposit Premium and Other Intangible Assets (Estimated future amortization expense for amortizable intangible assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2013	$ 6,060
Year ending December 31, 2014	4,564
Year ending December 31, 2015	3,552
Year ending December 31, 2016	2,711
Year ending December 31, 2017	1,873
Year ending December 31, 2018	1,037
Thereafter	469
Core Deposits [Member]
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2013	554
Year ending December 31, 2014	468
Year ending December 31, 2015	267
Year ending December 31, 2016	238
Year ending December 31, 2017	212
Year ending December 31, 2018	187
Thereafter	227
Mortgage Servicing Rights [Member]
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2013	5,473
Year ending December 31, 2014	4,053
Year ending December 31, 2015	3,243
Year ending December 31, 2016	2,432
Year ending December 31, 2017	1,621
Year ending December 31, 2018	811
Thereafter	0
Customer Relationships [Member]
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2013	33
Year ending December 31, 2014	43
Year ending December 31, 2015	42
Year ending December 31, 2016	41
Year ending December 31, 2017	40
Year ending December 31, 2018	39
Thereafter	$ 242

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

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- Definition

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.

+ References

No definition available.

+ Details

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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.

+ References

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- Definition

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

+ References

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

+ References

+ Details

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- Definition

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.

+ References

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