Employee Benefit Plans (Employee Savings and Stock Ownership Plan - Shares) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Stock Ownership Plan (ESOP) Disclosures
Shares contributed to ESOP (in shares)	11,077	9,918	16,151
Shares in ESOP (in shares)	72,362	83,439	93,357
Deferred shares, fair value	$ 4.3	$ 4.5	$ 4.4
Compensation expense	0.3	0.3	0.3
Defined Contribution Feature
Employee Stock Ownership Plan (ESOP) Disclosures
Compensation expense	$ 2.3

The amount of plan compensation cost recognized during the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

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- Definition

The fair value of shares held by the ESOP as of the balance sheet date in which no ESOP participant has a vested interest and no lender has a claim. The fair value of an ESOP share is the amount the seller could reasonably expect to receive for it in a current sale between a willing buyer and a willing seller, that is, other than in a forced or liquidation sale, which would be the market price of the stock if it is publicly traded.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

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Data Type:	xbrli:stringItemType
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- Definition

This item represents the number of shares provided to the Employee Stock Ownership Plan (ESOP) during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Sum of the allocated, committed-to-be-released and suspense shares of the entity held by the plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

+ Details

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Period Type:	instant

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