Summary of significant accounting policies - Estimated Useful Lives of Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	20 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	30 years
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	2 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	7 years
Furniture, fixtures, software and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	3 years
Furniture, fixtures, software and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	5 years
Software | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	5 years
Software | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives (in years)	7 years