Pensions and Postretirement Benefits - Schedule of Projected Benefit Obligations Amounts Recognized in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits
Defined Benefit Plan Disclosure
Long-term assets	$ 28.6	$ 16.8
Current liabilities	(0.9)	(0.5)
Long-term liabilities	(12.0)	(13.6)
Funded Status at End of Year	15.7	2.7
Other Benefits
Defined Benefit Plan Disclosure
Long-term assets	0.0	0.0
Current liabilities	(0.1)	(0.3)
Long-term liabilities	(3.0)	(3.5)
Funded Status at End of Year	$ (3.1)	$ (3.8)