Adjusted earnings before interest tax depreciation and amortization.

No definition available.

Name:	mlm_AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization
Namespace Prefix:	mlm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount by which consolidated debt, for purposes of calculating the debt covenant ratio, may be reduced for unrestricted cash and cash equivalents, provided no amounts are outstanding under the revolving credit facility and the AR credit facility.

+ References

No definition available.

+ Details

Name:	mlm_ConsolidatedDebtReductionForUnrestrictedCashAndCashEquivalentsForDebtCovenantCalculation
Namespace Prefix:	mlm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt instrument maturity date year.

+ References

No definition available.

+ Details

Name:	mlm_DebtInstrumentMaturityDateYear
Namespace Prefix:	mlm_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Eligible trade receivables.

+ References

No definition available.

+ Details

Name:	mlm_EligibleTradeReceivables
Namespace Prefix:	mlm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Increase in annual interest expense due to ongoing amortization of the terminated value of the Swap agreements.

+ References

No definition available.

+ Details

Name:	mlm_IncreaseInAnnualInterestExpenseDueToOngoingAmortizationOfTerminatedValueOfSwapAgreements
Namespace Prefix:	mlm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line of credit facility borrowing base.

+ References

No definition available.

+ Details

Name:	mlm_LineOfCreditFacilityBorrowingBase
Namespace Prefix:	mlm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum consolidated debt reduction for unrestricted cash and cash equivalents for debt covenant calculation.

+ References

No definition available.

+ Details

Name:	mlm_MaximumConsolidatedDebtReductionForUnrestrictedCashAndCashEquivalentsForDebtCovenantCalculation
Namespace Prefix:	mlm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessCombinationIntegrationRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

+ Details

Name:	us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

Name:	us-gaap_RatioOfIndebtednessToNetCapital1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=mlm_TexasIndustriesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=mlm_IncludingAcquisitionBridgeDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=mlm_ExcludingAcquisitionBridgeDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mlm_TradeReceivableCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mlm_TermLoanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mlm_SeniorNotesDueTwentyTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mlm_SixPointSixPercentSeniorNotesDueTwentyEighteenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt - Additional information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Debt Instrument [Line Items]
Maximum consolidated debt reduction for unrestricted cash and cash equivalents for debt covenant calculation			$ 200,000,000
Additional interest expense	$ 317,000	$ 295,000	624,000	$ 583,000
Maximum \| Texas Industries Inc.
Debt Instrument [Line Items]
Amendment consolidated EBITDA					$ 95,000,000
Acquisition integration expenses					70,000,000
Minimum
Debt Instrument [Line Items]
Reduction of consolidated debt in the debt ratio calculation			$ 50,000,000
Including Acquisition Bridge Debt \| Maximum
Debt Instrument [Line Items]
Debt covenant	3.50		3.50
Excluding Acquisition Bridge Debt \| Maximum
Debt Instrument [Line Items]
Debt covenant	3.75		3.75
Trade Receivable Facility
Debt Instrument [Line Items]
Credit facility commitment	$ 250,000,000		$ 250,000,000
Debt instrument maturity period			Sep. 30, 2016
Eligible trade receivables	450,791,000	311,792,000	$ 450,791,000	311,792,000	369,575,000
Credit facility borrowing base	377,688,000	258,787,000	377,688,000	258,787,000	313,428,000
Term Loan Facility
Debt Instrument [Line Items]
Credit facility commitment	250,000,000		250,000,000
Revolving Facility
Debt Instrument [Line Items]
Credit facility commitment	350,000,000		$ 350,000,000
Senior unsecured revolving facility, maturity period			5 years
Outstanding letters of credit	$ 2,507,000	$ 2,507,000	$ 2,507,000	$ 2,507,000	$ 2,507,000
9.25% Senior Notes due 2020 \| Texas Industries Inc.
Debt Instrument [Line Items]
Interest rate on notes					9.25%
Maturity date					2020
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Interest rate on notes	6.60%		6.60%
Maturity date			2018
Increase in annual interest expense due to ongoing amortization of the terminated value of the swap agreements			$ 1,200,000
London Interbank Offered Rate(LIBOR) \| Trade Receivable Facility
Debt Instrument [Line Items]
Basis spread on variable rate			0.70%