v3.26.1
MINERAL PROPERTIES, PLANT AND EQUIPMENT, NET - Components of Mineral Properties, Plant and Equipment, Net (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Property, Plant, and Equipment [Line Items]    
Total mineral properties, plant, and equipment $ 2,267,155 $ 2,148,869
Accumulated depreciation, plant and equipment (694,415) (658,074)
Accumulated depletion, mineral properties (491,165) (466,380)
Mineral properties, plant, and equipment, net 1,081,575 1,024,415
Finance lease, right-of-use asset, before accumulated amortization 200 500
Plant and equipment    
Property, Plant, and Equipment [Line Items]    
Total mineral properties, plant, and equipment 1,154,150 1,084,113
Construction in process    
Property, Plant, and Equipment [Line Items]    
Total mineral properties, plant, and equipment 85,903 67,469
Mineral properties subject to depletion    
Property, Plant, and Equipment [Line Items]    
Total mineral properties, plant, and equipment 880,393 833,213
Mineral properties not yet subject to depletion    
Property, Plant, and Equipment [Line Items]    
Total mineral properties, plant, and equipment 65,070 74,608
Exploration and evaluation assets    
Property, Plant, and Equipment [Line Items]    
Total mineral properties, plant, and equipment $ 81,639 $ 89,466