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DERIVATIVE INSTRUMENTS (Schedule of Notional Amounts of Outstanding Derivatives) (Details) - Designated as Hedging Instrument [Member] lb in Millions, gal in Millions, MMBTU in Millions, $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2020 CAD ($) MMBTU lb gal | Mar. 31, 2019 MMBTU lb gal | Dec. 31, 2019 CAD ($)
Natural Gas [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU | 50.4 | 20.1 |
Diesel [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Nonmonetary Notional Amount, Volume | 0.0 | 0.8 |
Derivative, Nonmonetary Notional Amount, Mass | lb | 28.8 | 0.0 |
Electricity [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Nonmonetary Notional Amount, Volume | 1.5 | 0.0 |
Canada, Dollars | Foreign Exchange Contract [Member] |  |  |
Derivative [Line Items] |  |  |
Derivative, Notional Amount | $ | $ 58.7 |  | $ 0.0

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- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959 + Details
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