Plant Closure and Divestitures - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended			3 Months Ended			9 Months Ended
	Oct. 31, 2021	Jun. 30, 2021	Feb. 28, 2021	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Gain on sale				$ 0.0		$ 0.0	$ 7.8	$ 0.0
Railroad And Utility Products And Services [Member] | Facility [Member] | Subsequent Event [Member]
Restructuring Cost and Reserve [Line Items]
Gain on sale	$ 23.0
Netherlands [Member]
Restructuring Cost and Reserve [Line Items]
Gain on sale		$ 0.3
West Virginia [Member] | Coal Tar Distillation [Member]
Restructuring Cost and Reserve [Line Items]
Gain on sale			$ 5.7
Cash proceed from sale			$ 2.6
Pennsylvania [Member] | Coal Tar Distillation [Member]
Restructuring Cost and Reserve [Line Items]
Gain on sale					$ 1.8