Debt instrument maturity date year.

No definition available.

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

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

- Definition

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

+ References

+ 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 effective interest rate at the end of the reporting period.

+ References

+ Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

Long Term Debt (Parenthetical) (Detail)	6 Months Ended
Long Term Debt (Parenthetical) (Detail)	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Maturity date	2018
Interest rate on notes	6.60%
7% Debentures, Due 2025
Debt Instrument [Line Items]
Maturity date	2025
Interest rate on notes	7.00%
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Maturity date	2037
Interest rate on notes	6.25%
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Maturity date	2024
Interest rate on notes	4.25%
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Maturity date	2017
Interest rate	1.38%	1.33%
Term Loan Facility, Due 2018
Debt Instrument [Line Items]
Maturity date	2018
Interest rate	1.69%	1.67%	1.65%
Revolving Facility
Debt Instrument [Line Items]
Credit Facility interest rate			1.40%
Trade Receivable Facility
Debt Instrument [Line Items]
Credit Facility interest rate	0.88%		0.75%