Revenues and Gross Profit - Total Revenues and Gross Profit by Product Line (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Product Information [Line Items]
Total revenues	$ 4,739.1	$ 4,244.3	$ 3,965.6
Gross profit (loss)	1,179.0	966.6	971.9
Interproduct Revenues
Product Information [Line Items]
Total revenues	(265.5)	(264.2)	(264.0)
Corporate
Product Information [Line Items]
Gross profit (loss)	3.0	7.6	6.9
Building Materials Business
Product Information [Line Items]
Total revenues	4,467.8	3,956.6	3,695.6
Gross profit (loss)	1,080.6	860.3	875.6
Building Materials Business | Operating Segments
Product Information [Line Items]
Total revenues	4,467.8	3,956.6	3,695.6
Gross profit (loss)	1,080.6	860.3	875.6
Building Materials Business | Operating Segments | Products and Services
Product Information [Line Items]
Total revenues	4,172.4	3,711.8	3,470.8
Gross profit (loss)	1,080.8	860.1	873.0
Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total revenues	271.3	287.7	270.0
Gross profit (loss)	95.4	98.7	89.4
Magnesia Specialties | Operating Segments | Products and Services
Product Information [Line Items]
Total revenues	249.9	268.6	252.7
Gross profit (loss)	99.4	102.9	94.1
Aggregates | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total revenues	2,756.7	2,365.8	2,145.6
Gross profit (loss)	807.9	608.4	602.3
Cement | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total revenues	439.1	387.8	371.2
Gross profit (loss)	143.4	126.2	117.0
Ready Mixed Concrete | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total revenues	948.1	963.8	936.0
Gross profit (loss)	78.8	74.2	91.6
Asphalt and Paving | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total revenues	294.0	258.6	282.0
Gross profit (loss)	50.7	51.3	62.1
Freight
Product Information [Line Items]
Total revenues	316.8	263.9	242.1
Freight | Building Materials Business
Product Information [Line Items]
Total revenues	295.4	244.8	224.8
Freight | Building Materials Business | Operating Segments
Product Information [Line Items]
Total revenues	295.4	244.8	224.8
Gross profit (loss)	(0.2)	0.2	2.6
Freight | Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total revenues	21.4	19.1	17.3
Gross profit (loss)	$ (4.0)	$ (4.2)	$ (4.7)