Revenues and Gross Profit - Total Revenues and Gross Profit (Loss) by Product Line (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Product Information [Line Items]
Total Revenues	$ 1,641.7	$ 1,377.9	$ 2,872.5	$ 2,360.3
Gross profit (loss)	425.2	385.1	581.3	559.8
Interproduct Revenues
Product Information [Line Items]
Total Revenues	(102.3)	(96.7)	(190.4)	(169.8)
Corporate
Product Information [Line Items]
Gross profit (loss)	1.6	0.5	(6.4)	(0.2)
Building Materials Business
Product Information [Line Items]
Total Revenues	1,560.0	1,302.1	2,713.8	2,213.6
Building Materials Business | Operating Segments
Product Information [Line Items]
Total Revenues	1,560.0	1,302.1	2,713.8	2,213.6
Gross profit (loss)	399.1	357.6	537.5	505.6
Building Materials Business | Operating Segments | Products and Services
Product Information [Line Items]
Total Revenues	1,449.2	1,225.3	2,526.2	2,082.0
Gross profit (loss)	400.8	356.9	537.9	505.1
Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total Revenues	81.7	75.8	158.7	146.7
Gross profit (loss)	24.5	27.0	50.2	54.4
Magnesia Specialties | Operating Segments | Products and Services
Product Information [Line Items]
Total Revenues	74.6	70.0	145.4	135.2
Gross profit (loss)	25.8	27.9	52.6	56.3
Aggregates | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	955.2	801.8	1,641.1	1,374.4
Gross profit (loss)	309.0	273.0	410.9	394.7
Cement | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	157.9	116.5	292.2	226.1
Gross profit (loss)	51.1	36.1	78.5	51.4
Ready Mixed Concrete | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	226.1	268.4	516.2	503.7
Gross profit (loss)	14.3	19.1	35.4	38.6
Asphalt and Paving | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	212.3	135.3	267.1	147.6
Gross profit (loss)	(26.4)	28.7	13.1	20.4
Freight
Product Information [Line Items]
Total Revenues	117.9	82.6	200.9	143.1
Freight | Building Materials Business
Product Information [Line Items]
Total Revenues	110.8	76.8	187.6	131.6
Freight | Building Materials Business | Operating Segments
Product Information [Line Items]
Total Revenues	110.8	76.8	187.6	131.6
Gross profit (loss)	1.7	0.7	0.4	0.5
Freight | Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total Revenues	7.1	5.8	13.3	11.5
Gross profit (loss)	$ (1.3)	$ (0.9)	$ (2.4)	$ (1.9)