Basic and Diluted Earnings Per Common Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Net earnings from continuing operations attributable to Martin Marietta Materials, Inc.	$ 42,334	$ 44,994
Less: Distributed and undistributed earnings attributable to unvested awards	153	298
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$ 42,181	$ 44,696
Basic weighted-average common shares outstanding	63,024	64,158
Effect of dilutive employee and director awards	295	192
Diluted weighted-average common shares outstanding	63,319	64,350