XML 88 R73.htm IDEA: XBRL DOCUMENT v3.8.0.1
Property, Plant, and Equipment (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Summary of Property, plant and equipment      
Property, plant, and equipment $ 891,789 $ 861,267  
Less allowances for depreciation, depletion, and amortization (636,211) (608,636)  
Property, plant, and equipment — net 255,578 252,631 $ 263,629
Land      
Summary of Property, plant and equipment      
Property, plant, and equipment 4,874 5,548  
Buildings      
Summary of Property, plant and equipment      
Property, plant, and equipment 137,196 135,729  
Machinery and equipment      
Summary of Property, plant and equipment      
Property, plant, and equipment 626,186 609,894  
Software      
Summary of Property, plant and equipment      
Property, plant, and equipment 40,575 39,550  
Construction in progress      
Summary of Property, plant and equipment      
Property, plant, and equipment 29,963 19,111  
Land Building Machinery and Equipment      
Summary of Property, plant and equipment      
Less allowances for depreciation, depletion, and amortization (615,134) (593,531)  
Property, plant, and equipment — net 223,660 216,301  
Capital leases      
Summary of Property, plant and equipment      
Property, plant, and equipment 10,912 10,913  
Less allowances for depreciation, depletion, and amortization (2,741) (2,492)  
Property, plant, and equipment — net 8,171 8,421  
Mineral resources      
Summary of Property, plant and equipment      
Property, plant, and equipment 4,979 4,979  
Mine development      
Summary of Property, plant and equipment      
Property, plant, and equipment 37,103 35,543  
Productive land      
Summary of Property, plant and equipment      
Less allowances for depreciation, depletion, and amortization (18,335) (12,613)  
Property, plant, and equipment — net $ 23,747 $ 27,909