Premises and Equipment Summary Composition (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	550,183us-gaap_PropertyPlantAndEquipmentGross
Accumulated depreciation	275,495
Premises and equipment,net	274,688us-gaap_PropertyPlantAndEquipmentNet	270,890us-gaap_PropertyPlantAndEquipmentNet
Land [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	52,790
Accumulated depreciation	0
Premises and equipment,net	52,790	50,668
Land Improvements [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	10,903
Accumulated depreciation	4,295
Premises and equipment,net	6,608	6,490
Land Improvements [Member] \| MaximumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	15 years
Land Improvements [Member] \| MinimumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	3 years
Building and Building Improvements [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	255,623
Accumulated depreciation	115,921
Premises and equipment,net	139,702	130,772
Building and Building Improvements [Member] \| MaximumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	39 years
Building and Building Improvements [Member] \| MinimumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	5 years
Computer Equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	35,929
Accumulated depreciation	28,411
Premises and equipment,net	7,518	10,397
Computer Equipment [Member] \| MaximumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	5 years
Computer Equipment [Member] \| MinimumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	3 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	161,008
Accumulated depreciation	105,261
Premises and equipment,net	55,747	58,259
Furniture and Fixtures [Member] \| MaximumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	15 years
Furniture and Fixtures [Member] \| MinimumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	3 years
Leasehold Improvements [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	33,930
Accumulated depreciation	21,607
Premises and equipment,net	12,323	$ 14,304
Leasehold Improvements [Member] \| MaximumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	30 years
Leasehold Improvements [Member] \| MinimumMember
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life of property, plant, and equipment	5 years

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.14)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 14

-Article 5

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- Definition

Amount before accumulated depreciation, depletion and amortization of 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, and furniture and fixtures.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 7

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- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

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