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, 2015
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2015	$ 9,231
Year ending December 31, 2016	8,090
Year ending December 31, 2017	7,071
Year ending December 31, 2018	6,032
Year ending December 31, 2019	4,940
Year ending December 31, 2020	3,815
Thereafter	4,845
Core deposit intangibles
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2015	2,078
Year ending December 31, 2016	2,467
Year ending December 31, 2017	2,180
Year ending December 31, 2018	1,925
Year ending December 31, 2019	1,667
Year ending December 31, 2020	1,423
Thereafter	2,224
Mortgage servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2015	6,480
Year ending December 31, 2016	4,754
Year ending December 31, 2017	4,075
Year ending December 31, 2018	3,396
Year ending December 31, 2019	2,716
Year ending December 31, 2020	2,037
Thereafter	2,037
Customer relationship intangible
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2015	32
Year ending December 31, 2016	41
Year ending December 31, 2017	40
Year ending December 31, 2018	39
Year ending December 31, 2019	38
Year ending December 31, 2020	37
Thereafter	166
Commercial servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Nine months ending December 31, 2015	641
Year ending December 31, 2016	828
Year ending December 31, 2017	776
Year ending December 31, 2018	672
Year ending December 31, 2019	519
Year ending December 31, 2020	318
Thereafter	$ 418

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

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- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ 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=26713463&loc=d3e16323-109275

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

No definition available.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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