Commitments and Contingencies - Additional Information (Detail) Claim in Thousands, $ in Millions		3 Months Ended			12 Months Ended
		Dec. 31, 2020 USD ($) Claim	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) Claim
Asbestos Related Matters [Member]
Other Commitments [Line Items]
Outstanding Active Pending Asbestos Claims | Claim		25			25
Asbestos remeasurement	[1]				$ 135.9
Percentage of Asbestos Asset Related to Coverage in Place Agreements		76.00%			76.00%
Asbestos Related Matters [Member] | Asset [Member]
Other Commitments [Line Items]
Asbestos remeasurement					$ (19.8)
Asbestos Related Matters [Member] | Liability [Member]
Other Commitments [Line Items]
Asbestos remeasurement	[1]				155.7
Asbestos Liability Gross Current And Noncurrent Ending Balance		$ 932.0			932.0
Asbestos Related Matters [Member]
Other Commitments [Line Items]
Asbestos Settlement Agreement Cash Proceeds				$ 66.4
Asbestos Related Costs (Benefit), Settlement Agreement		$ 52.1	$ (4.2)	$ 52.5
Continuing Operations [Member] | Asbestos Related Matters [Member]
Other Commitments [Line Items]
Asbestos remeasurement	[1]				$ 135.9

[1] In the third quarter of 2020, we extended our projection to include pending claims and claims expected to be filed through 2052, reflecting the full time period over which we expect asbestos-related claims to be filed against us.