Restructuring, Impairment and Other - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Restructuring And Related Activities [Abstract]
Employee termination costs	$ 2.3	$ 12.8	$ 3.8	$ 20.9
Other restructuring charges	7.6	14.0	11.6	18.1
Gain (loss) on sale of previously impaired assets	$ 1.8	$ (0.2)	$ 1.4	$ 1.5

Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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