Income Taxes Reconciliation of unrecognized tax benefit (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning of Period	$ 2.7us-gaap_UnrecognizedTaxBenefits	$ 6.7us-gaap_UnrecognizedTaxBenefits	$ 8.2us-gaap_UnrecognizedTaxBenefits
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	1.2	0.8	0.8
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	0.1	0	0.2
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities of Lapse of Applicate Statute of Limitations	(0.6)	(4.8)	(2.5)
Unrecognized Tax Benefits, End of Period	$ 3.4us-gaap_UnrecognizedTaxBenefits	$ 2.7us-gaap_UnrecognizedTaxBenefits	$ 6.7us-gaap_UnrecognizedTaxBenefits

Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities of Lapse of Applicate Statute of Limitations

No definition available.

+ Details

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- Definition

Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

+ Details

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- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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