Basic and Diluted Earnings Per Common Share (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Schedule of Earnings Per Share, Basic and Diluted, by Common Class
Net loss from continuing operations attributable to Martin Marietta Materials, Inc.	$ (27,739)	$ (36,143)
Less: Distributed and undistributed earnings attributable to unvested awards	(93)	(126)
Basic and diluted net loss available to common shareholders from continuing operations attributable to Martin Marietta Materials, Inc.	(27,832)	(36,269)
Basic and diluted net loss available to common shareholders from discontinued operations	(100)	(589)
Basic and diluted net loss available to common shareholders attributable to Martin Marietta Materials, Inc.	$ (27,932)	$ (36,858)
Basic and diluted weighted-average common shares outstanding	46,028	45,734

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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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

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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