Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Accrual for environmental loss contingencies, gross	$ 16.0	$ 16.4
Accrued environmental loss contingencies, current	5.6	4.1
Accrued environmental loss contingencies, noncurrent	$ 10.4	$ 12.3

Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable in twelve months or in the next operating cycle if longer.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant