Revenue Recognition - Schedule of Company's Total Revenues by Category for each Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue Recognition [Line Items]
Total	$ 1,811.7	$ 1,557.3	$ 4,684.2	$ 3,917.6
Building Materials Business
Revenue Recognition [Line Items]
Total	1,736.0	1,478.9	4,449.8	3,692.6
Products and Services
Revenue Recognition [Line Items]
Total	1,680.5	1,462.7	4,352.1	3,679.9
Products and Services | Building Materials Business
Revenue Recognition [Line Items]
Total	1,611.5	1,390.8	4,137.7	3,472.8
Freight
Revenue Recognition [Line Items]
Total	131.2	94.6	332.1	237.7
Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	124.5	88.1	312.1	219.8
Operating Segments | Building Materials Business East Group
Revenue Recognition [Line Items]
Total	773.6	684.1	1,866.9	1,714.4
Operating Segments | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	962.4	794.8	2,582.9	1,978.2
Operating Segments | Building Materials Business
Revenue Recognition [Line Items]
Total	1,736.0	1,478.9	4,449.8	3,692.6
Operating Segments | Magnesia Specialties
Revenue Recognition [Line Items]
Total	75.7	78.4	234.4	225.0
Operating Segments | Products and Services | Building Materials Business East Group
Revenue Recognition [Line Items]
Total	728.5	641.8	1,755.5	1,610.9
Operating Segments | Products and Services | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	883.0	749.0	2,382.2	1,861.9
Operating Segments | Products and Services | Magnesia Specialties
Revenue Recognition [Line Items]
Total	69.0	71.9	214.4	207.1
Operating Segments | Freight | Building Materials Business East Group
Revenue Recognition [Line Items]
Total	45.1	42.3	111.4	103.5
Operating Segments | Freight | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	79.4	45.8	200.7	116.3
Operating Segments | Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	124.5	88.1	312.1	219.8
Operating Segments | Freight | Magnesia Specialties
Revenue Recognition [Line Items]
Total	$ 6.7	$ 6.5	$ 20.0	$ 17.9