Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	$ 294.0	$ 296.0
Currency translation	0.4	(2.0)
Balance ending	294.4	294.0
Performance Chemicals [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	173.4	175.1
Currency translation	0.4	(1.7)
Balance ending	173.8	173.4
Railroad Products and Services [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	41.0	41.1
Currency translation	0.0	(0.1)
Balance ending	41.0	41.0
Utility Products [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Balance beginning	79.6	79.8
Currency translation	0.0	(0.2)
Balance ending	$ 79.6	$ 79.6