PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands |
Mar. 31, 2026 |
Dec. 31, 2025 |
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| PROPERTY, PLANT AND EQUIPMENT | ||
| Less: accumulated depreciation, depletion, and amortization | $ (276,533) | $ (261,609) |
| Total property, plant, and equipment, net | 517,090 | 511,943 |
| Plant and equipment | ||
| PROPERTY, PLANT AND EQUIPMENT | ||
| Property, plant and equipment, gross | 398,285 | 390,359 |
| Mining property and mineral rights | ||
| PROPERTY, PLANT AND EQUIPMENT | ||
| Property, plant and equipment, gross | 139,077 | 139,077 |
| Construction in process | ||
| PROPERTY, PLANT AND EQUIPMENT | ||
| Property, plant and equipment, gross | 28,975 | 22,264 |
| Capitalized mine development costs | ||
| PROPERTY, PLANT AND EQUIPMENT | ||
| Property, plant and equipment, gross | $ 227,286 | $ 221,852 |
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- Definition Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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