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Property, Plant and Equipment, Net - Schedule of Net Property, Plant and Equipment (Detail) - USD ($)
$ in Thousands
Sep. 30, 2023
Dec. 31, 2022
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 407,936 $ 393,797
Less: accumulated depreciation and depletion 152,292 134,954
Total property, plant and equipment, net 255,644 258,843
Machinery, equipment and tooling    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 40,114 36,483
SmartSystems    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 30,229 28,376
Vehicles    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 4,066 3,835
Furniture and fixtures    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 1,452 1,421
Plant and building    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 208,685 200,480
Real estate properties    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 6,184 6,155
Railroad and sidings    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 33,765 33,698
Land and land improvements    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 40,506 40,433
Asset retirement obligations    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 22,583 22,583
Mineral properties    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 7,442 7,442
Deferred mining costs    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 3,802 2,470
Construction in progress    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 9,108 $ 10,421