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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, 2018 | Dec. 31, 2016
Successor |  |  |  |
Reconciliation of Unrecognized Tax Benefits [Line Items] |  |  |  |
Balance at beginning of period |  |  | $ 12.7 |
Additions for current year tax positions |  | $ 0.8 | 1.8 |
Reductions for prior year tax positions |  | (0.5) | 0.0 |
Reductions for settlements with tax authorities |  | (0.1) | (0.5) |
Balance at end of period |  | 12.7 | $ 14.0 |
Predecessor |  |  |  |
Reconciliation of Unrecognized Tax Benefits [Line Items] |  |  |  |
Balance at beginning of period | $ 20.1 | $ 12.5 |  | $ 22.9
Additions for current year tax positions | 0.0 |  |  | 1.5
Reductions for prior year tax positions | (7.6) |  |  | (2.8)
Reductions for settlements with tax authorities | 0.0 |  |  | (1.5)
Balance at end of period | $ 12.5 |  |  | $ 20.1

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- Definition [Line Items] for Reconciliation of Unrecognized Tax Benefits [Table] + References No definition available. + Details
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- Definition 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 + Details
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- Definition 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 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + Details
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- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. + 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)(3) -URI http://asc.fasb.org/extlink&oid=84230637&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=84230637&loc=SL6600010-109319 + Details
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