Premises and Equipment (Summary of Premises and Equipment) (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Land	$ 12,987,000us-gaap_Land	$ 13,777,000us-gaap_Land
Buildings and improvements	95,843,000us-gaap_BuildingsAndImprovementsGross	97,586,000us-gaap_BuildingsAndImprovementsGross
Leasehold improvements	78,029,000us-gaap_LeaseholdImprovementsGross	74,127,000us-gaap_LeaseholdImprovementsGross
Fixtures and equipment	73,180,000us-gaap_FixturesAndEquipmentGross	70,819,000us-gaap_FixturesAndEquipmentGross
Data processing and software	175,887,000	162,693,000
Total premises and equipment	435,926,000us-gaap_PropertyPlantAndEquipmentGross	419,002,000us-gaap_PropertyPlantAndEquipmentGross
Less: Accumulated depreciation and amortization	(313,993,000)	(297,397,000)
Premises and equipment, net	121,933,000us-gaap_PropertyPlantAndEquipmentNet	121,605,000us-gaap_PropertyPlantAndEquipmentNet
Land	$ 27,900,000us-gaap_Depreciation	$ 31,100,000us-gaap_Depreciation	$ 34,100,000us-gaap_Depreciation

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

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.14)

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 14

-Article 5

+ Details

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- Definition

Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

+ References

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

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-Section 45

-Paragraph 4

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6812-107765

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- Definition

Amount before accumulated amortization of capitalized costs for computer software, including but not limited to, acquired and internally developed computer software.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 985

-SubTopic 20

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-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756

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Balance Type:	debit
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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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- Definition

Amount before accumulated depreciation of fixtures and equipment. Includes, but is not limited to, machinery, equipment, and engines.

+ References

No definition available.

+ Details

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- Definition

Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

+ References

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- Definition

Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

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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

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- Definition

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

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