XML 158 R64.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Selected accounting policies - Schedule of useful lives for property, plant, and equipment (Details)
 12 Months Ended
Dec. 31, 2019
Bottom of range [member] | Buildings [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 20 years
Bottom of range [member] | Machinery and equipment [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 7 years
Bottom of range [member] | Furniture and vehicles [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 5 years
Bottom of range [member] | Computer equipment [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 3 years
Top of range [member] | Buildings [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 40 years
Top of range [member] | Machinery and equipment [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 20 years
Top of range [member] | Furniture and vehicles [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 10 years
Top of range [member] | Computer equipment [member]  
Disclosure of detailed information about property, plant and equipment [line items]  
Useful life 7 years