Leases - Components of lease expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Short-term lease expense	$ 1.8	$ 2.0
Variable lease cost	1.6	2.1
Cost of products sold
Lessee, Lease, Description [Line Items]
Operating lease expense	3.1	3.0
Selling, general and administrative expenses
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 16.0	$ 17.6