XML 85 R72.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Derivative Financial Instruments and Hedging - Narrative (Details) € in Millions, lb in Millions, $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2018 USD ($) lb | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 EUR (€) | Dec. 31, 2018 EUR (€) | Jul. 31, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract] |  |  |  |  |  |
Maximum amount of time hedged for nickel requirements | 2023 |  |  |  |  |
Percentage of estimated annual nickel requirements | 12.00% |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Pre-tax cash flow hedge gain (loss) to be reclassified within twelve months | $ (5.7) |  |  |  |  |
Nickel [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative notional amount (in pounds of nickel) | lb | 12 |  |  |  |  |
Cash Flow Hedging [Member] | Natural gas contracts [Member] | Designated as Hedging Instrument [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Percentage of forecasted natural gas usage hedged for 2020 | 40.00% |  |  |  |  |
Pre-tax loss on ineffective portion of hedge |  |  | $ 1.3 |  |  |
Percentage Of Forecasted Natural Gas Usage Hedged for 2019 | 60.00% |  |  |  |  |
Cash Flow Hedging [Member] | Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Maturity Dates Through 2019 [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative notional amount | € |  |  |  |  | € 9.0 |
Fair Value Hedging [Member] | Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] | Maturity Dates Through 2017 [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Notional amount of derivatives entered during period | € |  |  |  | € 244.7 |  |
Cost of Sales [Member] | Fair Value Hedging [Member] | Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Gain (loss) on derivatives |  | $ (2.7) | $ 1.0 |  |  |
2022 Term Loan [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  | 5.44%
2022 Term Loan [Member] | Interest Rate Swap [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative notional amount |  |  |  |  |  | $ 50.0

X
- Definition Derivative, Notional Amount, Contracts Entered During Period + References No definition available. + Details
Name: | ati_DerivativeNotionalAmountContractEnteredDuringPeriod
Namespace Prefix: | ati_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments + References No definition available. + Details
Name: | ati_MaximumAmountOfTimeHedgedForNickelRequirements
Namespace Prefix: | ati_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Of Forecasted Natural Gas Usage Hedged for Year 1 + References No definition available. + Details
Name: | ati_PercentageOfForecastedNaturalGasUsageHedgedforYear1
Namespace Prefix: | ati_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate notional amount of price risk derivatives for instruments with notional amounts expressed in percentage of estimated annual domestic (U.S.) usage + References No definition available. + Details
Name: | ati_PercentageOfForecastedNaturalGasUsageHedgedforYear2
Namespace Prefix: | ati_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate notional amount of price risk derivatives for instruments with notional amounts expressed in percentage of annual estimated usage in production + References No definition available. + Details
Name: | ati_PercentageOfRawMaterialUsageHedged
Namespace Prefix: | ati_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | invest_DerivativeNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994 + Details
Name: | us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal mass used to calculate payments on a derivative instrument. + References No definition available. + Details
Name: | us-gaap_DerivativeNonmonetaryNotionalAmountMass
Namespace Prefix: | us-gaap_
Data Type: | num:massItemType
Balance Type: | na
Period Type: | duration

X
- Definition The loss recognized in earnings during the reporting period representing the amount of the cash flow hedges' ineffectiveness. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959 + Details
Name: | us-gaap_LossOnCashFlowHedgeIneffectiveness
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=ati_NickelMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=ati_NaturalGasContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeForwardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ati_DerivativeMaturityRangeAxis=ati_MaturityDatesThrough2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ati_DerivativeMaturityRangeAxis=ati_MaturityDatesThrough2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ati_A2022TermLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |