Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Income Taxes
Income tax provisions	$ 9.3	$ 10.6	$ 21.5	$ 12.1
Effective tax rate (as a percent)	20.00%	31.70%	25.40%	23.90%
Release of reserves for uncertain tax positions as a result of an audit settlement	5.5		5.5
Effective tax rate excluding audit settlements (as a percent)	31.80%		31.90%
New Clean Energy Manufacturing Tax Credits				$ 3.5
Effective tax rate excluding New Clean Energy Manufacturing Tax Credits (as a percent)				30.80%

Represents the effective tax rate for the entity excluding the effect of any audit settlement on the reserves for uncertain tax positions.

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Represents the effective tax rate for the entity excluding any tax credits generated or utilized under enacted tax laws during the period.

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The gross amount of decreases in unrecognized tax benefits resulting from audit settlements with taxing authorities.

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A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-Paragraph 47
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Income Tax Expense (or Benefit)
-URI http://asc.fasb.org/extlink&oid=6515339

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-Publisher SEC
-Name Regulation S-X (SX)
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-Section 08
-Paragraph h
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 45
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Accounting Standards Codification
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The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to investment tax credits generated or utilized under enacted tax laws during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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