Goodwill and Other Intangible Assets - Intangible Assets Deemed to Indefinite Life that are Therefore Not Amortized (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	$ 35.8	$ 36.0
Operating Permits
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	6.6	6.6
Use Rights
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	26.7	26.7
Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	2.5	2.7
Building Materials Business
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	33.3	33.5
Building Materials Business | Operating Permits
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	6.6	6.6
Building Materials Business | Use Rights
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	26.7	26.7
Building Materials Business | Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	0.0	0.2
Magnesia Specialties
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	2.5	2.5
Magnesia Specialties | Operating Permits
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	0.0	0.0
Magnesia Specialties | Use Rights
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	0.0	0.0
Magnesia Specialties | Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	$ 2.5	$ 2.5