Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets:
Loss carryforwards	$ 128.6	$ 139.8
Asbestos	116.7	101.5
Employee benefits	64.7	59.4
Accruals	59.3	46.0
Credit carryforwards	3.4	2.5
Other	27.0	20.5
Gross deferred tax assets	399.7	369.7
Less: Valuation allowance	123.0	129.8	$ 141.0	$ 170.0
Net deferred tax assets	276.7	239.9
Deferred Tax Liabilities:
Intangibles	(40.9)	(43.0)
Undistributed earnings	(49.2)	(33.8)
Accelerated depreciation	(30.3)	(26.9)
Investment	0.5	(0.2)
Total deferred tax liabilities	(119.9)	(103.9)
Net deferred tax assets	$ 156.8	$ 136.0