Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - PPE (Details)

v3.20.4
Summary of Significant Accounting Policies - PPE (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Property, plant and equipment      
Depreciation and amortization expense $ 8,806 $ 8,256 $ 7,613
Repairs and maintenance expenses $ 6,089 $ 6,256 $ 6,032
Land improvements and buildings | Minimum      
Property, plant and equipment      
Estimated useful lives 15 years    
Land improvements and buildings | Maximum      
Property, plant and equipment      
Estimated useful lives 40 years    
Leasehold Improvements      
Property, plant and equipment      
Estimated useful lives 12 years    
Leasehold Improvements | Minimum      
Property, plant and equipment      
Estimated useful lives 12 years    
Machinery and equipment | Minimum      
Property, plant and equipment      
Estimated useful lives 3 years    
Machinery and equipment | Maximum      
Property, plant and equipment      
Estimated useful lives 20 years    
Furniture and fixtures | Minimum      
Property, plant and equipment      
Estimated useful lives 3 years    
Furniture and fixtures | Maximum      
Property, plant and equipment      
Estimated useful lives 12 years    
Mobile equipment and other | Minimum      
Property, plant and equipment      
Estimated useful lives 3 years    
Mobile equipment and other | Maximum      
Property, plant and equipment      
Estimated useful lives 10 years