Summary of Significant Accounting Policies - Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Line Items]
Average required reserve balance	$ 40.3	$ 48.0
Historical loss period used in estimating loan loss reserve	72 months
Reserve coverage period in historical losses	1 year 11 months 22 days	1 year 8 months 5 days
Compensating Balance, Amount	$ 0us-gaap_CompensatingBalanceAmount
Commercial Loan
Accounting Policies [Line Items]
Reserve coverage period in historical losses	2 years 3 months 12 days	2 years 5 months

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Allowance for Loan and Lease Losses, Current Reserve Coverage Period in Historical Losses

+ References

No definition available.

+ Details

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- Definition

Allowance for Loan and Lease Losses, Reserve Estimate Methodology, Historical Loss Period Factor

+ References

No definition available.

+ Details

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- Definition

The amount of a specific compensating balance arrangement that is maintained under an agreement for a bank loan or future credit availability.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

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 210.5-02.1)

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

+ Details

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- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ References

+ Details

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- Details

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