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DERIVATIVE INSTRUMENTS - Estimated Losses in Future Periods (Details) - Designated as Hedging Instrument [Member] $ in Millions | 6 Months Ended
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Jun. 30, 2020 USD ($)
Natural Gas [Member] |
Derivative Instruments, Gain (Loss) [Line Items] |
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred | $ (4.6)
Zinc [Member] |
Derivative Instruments, Gain (Loss) [Line Items] |
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred | 0.6
Electricity [Member] |
Derivative Instruments, Gain (Loss) [Line Items] |
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred | $ (1.0)

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- Definition The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80845-113994 + Details
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