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

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-Name Accounting Standards Codification

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-Section S99

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-Publisher SEC

-Name Regulation S-X (SX)

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-Section 02

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

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-Topic 840

-SubTopic 20

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-Paragraph 2

-Subparagraph (a)

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Amount of required minimum rental payments maturing in the next fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing after the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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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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-Name Accounting Standards Codification

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-Section 50

-Paragraph 1

-Subparagraph (b)

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-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.13)

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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

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-Section S99

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

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-Name Regulation S-X (SX)

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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.

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Premises and Equipment and Lease Commitments (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Premises and equipment, Gross	$ 143,849,000us-gaap_PropertyPlantAndEquipmentGross	$ 139,795,000us-gaap_PropertyPlantAndEquipmentGross
Accumulated depreciation and amortization	(72,273,000)	(67,145,000)
Premises and equipment, net	71,576,016us-gaap_PropertyPlantAndEquipmentNet	72,649,574us-gaap_PropertyPlantAndEquipmentNet
Depreciation and amortization expense	5,100,000	6,000,000	6,600,000
Rent expense	4,900,000us-gaap_LeaseAndRentalExpense	4,400,000us-gaap_LeaseAndRentalExpense	4,100,000us-gaap_LeaseAndRentalExpense
Future minimum lease payments due under operating leases [Abstract]
2015	4,093,000
2016	4,189,000
2017	4,042,000
2018	3,829,000
2019	3,732,000
Thereafter	25,285,000
Total	45,170,000
Land [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, Gross	19,829,000	19,281,000
Buildings [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, Gross	50,458,000	48,558,000
Buildings [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Range of Useful Lives	15 years
Buildings [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Range of Useful Lives	30 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, Gross	21,589,000	20,283,000
Leasehold Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Range of Useful Lives	15 years
Leasehold Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Range of Useful Lives	20 years
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, Gross	$ 51,973,000	$ 51,673,000
Furniture and Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Range of Useful Lives	3 years
Furniture and Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Range of Useful Lives	15 years