RELATED PARTIES (Narrative) (Details) - USD ($) $ in Millions |
9 Months Ended | 12 Months Ended | |
|---|---|---|---|
Sep. 30, 2019 |
Dec. 31, 2017 |
Dec. 31, 2018 |
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| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý |
| Noncontrolling Interest, Ownership Percentage by Parent | 100.00% | Ìý | Ìý |
| Empire | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý |
| Noncontrolling Interest, Ownership Percentage by Parent | Ìý | 100.00% | Ìý |
| Purchase of Noncontrolling Interest | Ìý | $ 132.7 | Ìý |
| Other Liabilities [Member] | Empire | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý |
| Noncontrolling Interest Purchase, Installment Amount | $ 44.2 | Ìý | Ìý |
| Hibbing [Member] | Ìý | Ìý | Ìý |
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý |
| Ownership interest, equity method investment | 23.00% | Ìý | 23.00% |
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- Definition Noncontrolling Interest Purchase, Installment Amount No definition available.
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- Definition Purchase of Noncontrolling Interest No definition available.
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. No definition available.
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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. No definition available.
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