Revenues and Gross Profit - Total Revenues and Gross Profit (Loss) by Product Line (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Product Information [Line Items]
Total Revenues	$ 1,994.1	$ 1,811.7	$ 5,169.0	$ 4,684.2
Gross profit (loss)	676.0	487.8	1,539.2	1,069.1
Interproduct Revenues
Product Information [Line Items]
Total Revenues	(141.9)	(104.6)	(350.5)	(296.0)
Corporate
Product Information [Line Items]
Gross profit (loss)	5.1	(2.1)	3.8	(8.5)
Building Materials Business
Product Information [Line Items]
Total Revenues	1,918.6	1,736.0	4,929.6	4,449.8
Building Materials Business | Operating Segments
Product Information [Line Items]
Total Revenues	1,918.6	1,736.0	4,929.6	4,449.8
Gross profit (loss)	649.5	469.3	1,461.3	1,006.7
Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total Revenues	75.5	75.7	239.4	234.4
Gross profit (loss)	21.4	20.6	74.1	70.9
Aggregates | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total Revenues	1,216.3	1,130.7	3,279.6	2,945.0
Gross profit (loss)	440.6	333.6	1,049.5	743.6
Cement | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total Revenues	199.1	168.2	565.3	469.0
Gross profit (loss)	108.7	67.3	249.0	144.8
Ready Mixed Concrete | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total Revenues	285.2	227.7	776.5	745.4
Gross profit (loss)	34.1	18.7	80.7	55.3
Asphalt and Paving | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total Revenues	359.9	314.0	658.7	586.4
Gross profit (loss)	$ 66.1	$ 49.7	$ 82.1	$ 63.0