v3.25.2
Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) - USD ($)
$ in Thousands
Jun. 30, 2025
Dec. 31, 2024
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment $ 2,869,507 $ 2,630,683
Less accumulated depreciation, depletion and amortization 1,203,446 1,123,553
Property, plant and equipment, net 1,666,061 1,507,130
Land [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment 28,732 28,130
Buildings And Improvements [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment 131,741 123,662
Plant, Machinery, Mining Equipment And Transportation Vehicles [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment 1,388,134 1,259,620
Mineral Rights And Reserves [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment 372,817 379,065
Office And Computer Equipment [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment 19,400 9,654
Mine Development [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment 575,035 550,110
Asset Retirement Obligation Asset [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment 94,068 90,318
Construction In Process [Member]    
Property Plant And Equipment [Line Items]    
Total cost of property, plant and equipment $ 259,580 $ 190,124