Accounting Policies - Basic and Diluted Earnings from Continuing Operations Per Common Share (Detail) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net earnings from continuing operations attributable to Martin Marietta	$ 1,199.8	$ 856.3	$ 702.0
Less: distributed and undistributed earnings attributable to unvested participating securities	0.0	0.0	0.2
Basic net earnings from continuing operations attributable to common shareholders attributable to Martin Marietta	1,199.8	856.3	701.8
Diluted net earnings from continuing operations attributable to common shareholders attributable to Martin Marietta	$ 1,199.8	$ 856.3	$ 701.8
Basic weighted-average common shares outstanding	61.9	62.3	62.4
Effect of dilutive employee and director awards	0.2	0.2	0.2
Diluted weighted-average common shares outstanding	62.1	62.5	62.6