BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Equity Method Investments) (Details) (Details) |
Mar. 31, 2020 |
|---|---|
| Combined Metals of Chicago, LLC [Member] | |
| Schedule of Equity Method Investments [Line Items] | |
| Equity Method Investment, Ownership Percentage | 40.00% |
| Hibbing Taconite Company [Member] | |
| Schedule of Equity Method Investments [Line Items] | |
| Equity Method Investment, Ownership Percentage | 23.00% |
| Spartan Steel Coating, LLC [Member] | |
| Schedule of Equity Method Investments [Line Items] | |
| Equity Method Investment, Ownership Percentage | 48.00% |
| X | ||||||||||
- 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
|
| 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. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|