Segments - Financial Data for Continuing Operations for Company's Reportable Business Segments (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Total Revenues	$ 1,820.8	$ 1,641.7	$ 3,174.9	$ 2,872.5
Earnings (Loss) from operations	463.3	478.6	659.3	538.4
Building Materials Business
Segment Reporting Information [Line Items]
Total Revenues	1,740.3	1,560.0	3,011.0	2,713.8
Earnings (Loss) from operations	467.1	485.1	670.7	556.1
Operating Segments | Building Materials Business East Group
Segment Reporting Information [Line Items]
Total Revenues	735.1	674.5	1,264.7	1,093.3
Earnings (Loss) from operations	227.5	210.6	336.4	238.5
Operating Segments | Building Materials Business West Group
Segment Reporting Information [Line Items]
Total Revenues	1,005.2	885.5	1,746.3	1,620.5
Earnings (Loss) from operations	239.6	274.5	334.3	317.6
Operating Segments | Magnesia Specialties
Segment Reporting Information [Line Items]
Total Revenues	80.5	81.7	163.9	158.7
Earnings (Loss) from operations	23.3	20.3	43.9	41.8
Operating Segments | Building Materials Business
Segment Reporting Information [Line Items]
Total Revenues	1,740.3	1,560.0	3,011.0	2,713.8
Corporate
Segment Reporting Information [Line Items]
Earnings (Loss) from operations	$ (27.1)	$ (26.8)	$ 55.3	$ (59.5)