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Derivatives and Fair Value Measurements Texuals (Details) AUD in Millions, $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Sep. 30, 2018 $ / AUD | Dec. 31, 2017 AUD
Predecessor |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Currency Options | $ | $ 257.3 |  |  |
Foreign Exchange Contract [Member] | Successor |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Derivative, Notional Amount | AUD |  |  |  | AUD 1,125.0
Minimum | Foreign Exchange Contract [Member] | Scenario, Forecast |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Derivative, Exchange Rate Cap | $ / AUD |  |  | 0.79 |
Maximum | Foreign Exchange Contract [Member] | Scenario, Forecast |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Derivative, Exchange Rate Cap | $ / AUD |  |  | 0.83 |
Gains realized on previously monetized foreign currency cash flow hedges [Member] | Predecessor |  |  |  |
Derivatives, Fair Value [Line Items] |  |  |  |
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net | $ |  | $ 14.9 |  |

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition Cap rate on a foreign currency derivative for example, but not limited to, a cap or a collar. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative liability, measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19279-110258 + Details
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- Definition The amount of net gains or losses on foreign currency cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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