Impairment and Closure Charges - Long-lived tangible asset impairment and closure charges (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Long-lived tangible asset impairment	$ 0.0	$ 0.0	$ 17.1	$ 0.0
Closure charges	0.2	0.3	0.9	0.5
Total long-lived asset impairment and closure charges	$ 0.2	$ 0.3	$ 18.0	$ 0.5

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes, but is not limited to, one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and termination benefits associated with an ongoing benefit arrangement. Excludes expenses associated with special or contractual termination benefits, a discontinued operation or an asset retirement obligation.

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