Annual report pursuant to Section 13 and 15(d)

Property, Plant and Equipment (Details)

v3.8.0.1
Property, Plant and Equipment (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 231,517 $ 457,510
Less accumulated depreciation 142,618 251,288
Net book value 88,899 206,222
Land    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 4,972 10,463
Buildings    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 34,653 65,894
Property, plant and equipment, estimated useful life 25 years  
Machinery and equipment    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 141,704 238,029
Furniture and fixtures    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 4,450 5,570
Transportation equipment    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross 2,667 3,814
Improvements    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 42,975 128,437
Property, plant and equipment, estimated useful life 15 years  
Construction in progress    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, gross $ 96 $ 5,303
Minimum    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 3 years  
Minimum | Machinery and equipment    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 3 years  
Minimum | Furniture and fixtures    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 3 years  
Minimum | Transportation equipment    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 3 years  
Maximum    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 25 years  
Maximum | Machinery and equipment    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 25 years  
Maximum | Furniture and fixtures    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 5 years  
Maximum | Transportation equipment    
Property, Plant and Equipment [Line Items]    
Property, plant and equipment, estimated useful life 5 years