Debt (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014 Revolving Loans	Dec. 31, 2013 Revolving Loans	Jun. 30, 2014 Amended Credit Agreement	May 31, 2011 Amended Credit Agreement	Jun. 30, 2014 Other revolving loans
Revolving loans
Weighted Average Interest Rate (as a percent)			1.30%
Total Amount Committed by Lenders	$ 542.3		$ 250.0	$ 250.0	$ 292.3
Outstanding Borrowings	112.5		112.5
Outstanding Letters of Credit	155.5	171.2	7.4		148.1
Total Amount Available	$ 274.3		$ 130.1		$ 144.2

Weighted average interest rate of debt outstanding.

No definition available.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Details

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- Definition

Amount borrowed under the credit facility as of the balance sheet date.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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