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Income Taxes Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 01, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Predecessor
Reconciliation of Unrecognized Tax Benefits [Line Items]
Unrecognized Tax Benefits	$ 12.5		$ 20.1	$ 22.9	$ 44.5
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	0.0		1.5	2.3
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(7.6)		(2.8)	(23.5)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	0.0		$ (1.5)	$ (0.4)
Successor
Reconciliation of Unrecognized Tax Benefits [Line Items]
Unrecognized Tax Benefits	$ 12.5	$ 12.7
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions		0.8
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions		(0.5)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities		$ (0.1)

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[Line Items] for Reconciliation of Unrecognized Tax Benefits [Table]

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Amount of unrecognized tax benefits.

+ 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)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

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Amount of decrease 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
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-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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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)(3)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

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

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-Name Accounting Standards Codification
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-Paragraph 15A
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