Revenue Recognition - Schedule of Company's Total Revenues by Category for each Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue Recognition [Line Items]
Total	$ 1,641.7	$ 1,377.9	$ 2,872.5	$ 2,360.3
Building Materials Business
Revenue Recognition [Line Items]
Total	1,560.0	1,302.1	2,713.8	2,213.6
Products and Services
Revenue Recognition [Line Items]
Total	1,523.8	1,295.3	2,671.6	2,217.2
Products and Services | Building Materials Business
Revenue Recognition [Line Items]
Total	1,449.2	1,225.3	2,526.2	2,082.0
Freight
Revenue Recognition [Line Items]
Total	117.9	82.6	200.9	143.1
Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	110.8	76.8	187.6	131.6
Operating Segments | Building Materials Business East Group
Revenue Recognition [Line Items]
Total	674.5	635.3	1,093.3	1,030.2
Operating Segments | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	885.5	666.8	1,620.5	1,183.4
Operating Segments | Building Materials Business
Revenue Recognition [Line Items]
Total	1,560.0	1,302.1	2,713.8	2,213.6
Operating Segments | Magnesia Specialties
Revenue Recognition [Line Items]
Total	81.7	75.8	158.7	146.7
Operating Segments | Products and Services | Building Materials Business East Group
Revenue Recognition [Line Items]
Total	632.4	596.5	1,027.0	969.1
Operating Segments | Products and Services | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	816.8	628.8	1,499.2	1,112.9
Operating Segments | Products and Services | Magnesia Specialties
Revenue Recognition [Line Items]
Total	74.6	70.0	145.4	135.2
Operating Segments | Freight | Building Materials Business East Group
Revenue Recognition [Line Items]
Total	42.1	38.8	66.3	61.1
Operating Segments | Freight | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	68.7	38.0	121.3	70.5
Operating Segments | Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	110.8	76.8	187.6	131.6
Operating Segments | Freight | Magnesia Specialties
Revenue Recognition [Line Items]
Total	$ 7.1	$ 5.8	$ 13.3	$ 11.5