Basic and Diluted Earnings (Loss) Per Common Share (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net earnings (loss) from continuing operations attributable to Martin Marietta Materials, Inc.	$ 6,126	$ (21,603)
Less: Distributed and undistributed earnings attributable to unvested awards	1,369	67
Basic and diluted net earnings (loss) available to common shareholders from continuing operations attributable to Martin Marietta Materials, Inc.	4,757	(21,670)
Basic and diluted net loss available to common shareholders from discontinued operations		(15)
Basic and diluted net earnings (loss) available to common shareholders attributable to Martin Marietta Materials, Inc.	$ 4,757	$ (21,685)
Basic weighted-average common shares outstanding	67,411	46,315
Effect of dilutive employee and director awards	265
Diluted weighted-average common shares outstanding	67,676	46,315

Basic and diluted net income loss attributable to common shareholders of reporting entity.

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Income loss from continuing operations net of tax attributable to common shareholders of reporting entity.

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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Amount of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Amount of earnings (loss) distributed and earnings (loss) allocated to participating securities for the diluted earnings (loss) per share or per unit calculation under the two-class method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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