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Commitments and Contingencies - Additional Information (Detail) (USD $)
 3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2013
Dec. 31, 2014
Mar. 31, 2014
Commitments and Contingencies [Line Items]        
Due from affiliate $ 6,000,000us-gaap_DueFromAffiliates   $ 6,000,000us-gaap_DueFromAffiliates $ 6,000,000us-gaap_DueFromAffiliates
Percentage of employees represented in labor union 13.00%mlm_PercentageOfEmployeesRepresentedInLaborUnion      
Cement        
Commitments and Contingencies [Line Items]        
Percentage of employees represented in labor union 100.00%mlm_PercentageOfEmployeesRepresentedInLaborUnion
/ us-gaap_ProductOrServiceAxis
= mlm_CementMember		      
Magnesia Specialties        
Commitments and Contingencies [Line Items]        
Percentage of employees represented in labor union 100.00%mlm_PercentageOfEmployeesRepresentedInLaborUnion
/ us-gaap_ProductOrServiceAxis
= mlm_MagnesiaSpecialtiesMember		      
Revolving Line Of Credit Expires In July 2013        
Commitments and Contingencies [Line Items]        
Guarantee of affiliate's obligations 25,000,000us-gaap_GuaranteeObligationsMaximumExposure
/ us-gaap_GuaranteeObligationsByNatureAxis
= mlm_RevolvingLineOfCreditExpiresInJulyTwoThousandThirteenMember		      
Loan Due May 2016        
Commitments and Contingencies [Line Items]        
Loan to affiliate   3,402,000us-gaap_PaymentsForAdvanceToAffiliate
/ us-gaap_GuaranteeObligationsByNatureAxis
= mlm_LoanDueMayTwoThousandSixteenMember		    
Due from affiliate     $ 1,808,000us-gaap_DueFromAffiliates
/ us-gaap_GuaranteeObligationsByNatureAxis
= mlm_LoanDueMayTwoThousandSixteenMember		 $ 2,773,000us-gaap_DueFromAffiliates
/ us-gaap_GuaranteeObligationsByNatureAxis
= mlm_LoanDueMayTwoThousandSixteenMember