Debt instrument effective interest rate.

No definition available.

Name:	mlm_DebtInstrumentEffectiveInterestRate
Namespace Prefix:	mlm_
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Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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=64930785&loc=d3e28551-108399

+ Details

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

- 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=64930785&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
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

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

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

- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=mlm_FourPointTwoFivePercentSeniorNotesDueTwentyTwentyFourMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=mlm_SevenPercentDebenturesDueTwentyTwentyFiveMember
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- Details

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- Details

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- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=mlm_FloatingRateSeniorNotesDueTwentyNineteenMember
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Schedule of Principal Amount, Effective Interest Rate and Maturity Date for Corporation's Senior Notes (Detail) - USD ($)		12 Months Ended
	Dec. 20, 2017	Dec. 31, 2017	May 22, 2017
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Principal Amount	$ 300,000,000	$ 300,000,000
Effective Interest Rate		6.81%
Maturity Date	Apr. 15, 2018	Apr. 15, 2018
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Principal Amount		$ 400,000,000
Effective Interest Rate		4.25%
Maturity Date		Jul. 02, 2024
7% Debentures, Due 2025
Debt Instrument [Line Items]
Principal Amount		$ 125,000,000
Effective Interest Rate		7.12%
Maturity Date		Dec. 01, 2025
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Principal Amount		$ 300,000,000	$ 300,000,000
Effective Interest Rate		3.47%
Maturity Date		Jun. 01, 2027
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Principal Amount	$ 500,000,000	$ 500,000,000
Effective Interest Rate		3.53%
Maturity Date		Dec. 15, 2027
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Principal Amount		$ 230,000,000
Effective Interest Rate		6.45%
Maturity Date		May 01, 2037
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Principal Amount	600,000,000	$ 600,000,000
Effective Interest Rate		4.27%
Maturity Date		Dec. 15, 2047
Floating Rate Notes, Due 2019
Debt Instrument [Line Items]
Principal Amount	$ 300,000,000	$ 300,000,000
Effective Interest Rate		2.13%
Debt Instrument Effective Interest Rate		Three-month LIBOR + 0.50%
Maturity Date	Dec. 20, 2019	Dec. 20, 2019
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Principal Amount		$ 300,000,000	$ 300,000,000
Effective Interest Rate		2.10%
Debt Instrument Effective Interest Rate		Three-month LIBOR + 0.65%
Maturity Date		May 22, 2020