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Derivative Financial Instruments and Hedging - Schedule of Derivative Instruments (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
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Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | $ 3.4 | $ 16.5
Fair value of derivative liability | 10.4 | 5.5
Designated as Hedging Instrument [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | 3.0 | 16.4
Fair value of derivative liability | 10.4 | 5.5
Not Designated as Hedging Instrument [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | 0.4 | 0.1
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative liability | 0.6 | 0.0
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Prepaid expenses and other current assets [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | 0.4 | 0.1
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative liability | 0.2 | 0.0
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other Liabilities [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative liability | 0.3 | 0.0
Nickel and other raw material contracts [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other current assets [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | 1.2 | 10.5
Nickel and other raw material contracts [Member] | Designated as Hedging Instrument [Member] | Other Assets [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | 0.8 | 5.5
Nickel and other raw material contracts [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative liability | 6.8 | 2.1
Nickel and other raw material contracts [Member] | Designated as Hedging Instrument [Member] | Other Liabilities [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative liability | 2.1 | 2.2
Natural gas contracts [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other current assets [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | 0.8 | 0.1
Natural gas contracts [Member] | Designated as Hedging Instrument [Member] | Other Assets [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative asset | 0.2 | 0.3
Natural gas contracts [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative liability | 0.1 | 0.9
Natural gas contracts [Member] | Designated as Hedging Instrument [Member] | Other Liabilities [Member] |  |
Derivatives, Fair Value [Line Items] |  |
Fair value of derivative liability | $ 0.3 | $ 0.3

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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=109247956&loc=SL51823488-111719 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959 + Details
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