Company's Liability for Environmental Obligations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Environmental Exit Cost [Line Items]
Total Balance at Beginning of Period	$ 2.1	$ 2.7
Additions	0.9	0.2
Less: Payments / Reductions	0.3	0.8
Total Balance at End of Period	2.7	2.1
Less: Current Portion	0.5	0.3
Noncurrent Balance at End of Period	$ 2.2	$ 1.8