XML 30 R37.htm IDEA: XBRL DOCUMENT
v3.19.3

Significant Accounting Policies - Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Equity [Abstract] |  |  |  |
Balance at beginning of period, Net Noncurrent Deferred Tax Assets | $ 82,417 | $ 78,619 | $ 84,207 | $ 80,116
Tax effect of other comprehensive earnings, Net Noncurrent Deferred Tax Assets | (899) | (1,326) | (2,689) | (2,823)
Balance at end of period, Net Noncurrent Deferred Tax Assets | 81,518 | 77,293 | 81,518 | 77,293
Balance at beginning of period, Pension and Postretirement Benefit Plans | 82,417 | 78,619 | 84,207 | 79,938
Tax effect of other comprehensive earnings, Pension and Postretirement Benefit Plans | (899) | (1,326) | (2,689) | (2,645)
Balance at end of period, Pension and Postretirement Benefit Plans | $ 81,518 | $ 77,293 | $ 81,518 | 77,293
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap |  |  |  | 178
Tax effect of other comprehensive earnings, Unamortized Value of Terminated Forward Starting Interest Rate Swap |  |  |  | $ (178)

X
- Definition Accumulated other comprehensive loss noncurrent deferred tax assets net. + References No definition available. + Details
Name: | mlm_AccumulatedOtherComprehensiveLossNoncurrentDeferredTaxAssetsNet
Namespace Prefix: | mlm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Accumulated other comprehensive loss, noncurrent deferred tax assets, other comprehensive earnings, tax effect, pension and postretirement benefit plans. + References No definition available. + Details
Name: | mlm_AccumulatedOtherComprehensiveLossNoncurrentDeferredTaxAssetsOtherComprehensiveEarningsTaxEffectPensionAndPostretirementBenefitPlans
Namespace Prefix: | mlm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Accumulated other comprehensive loss noncurrent deferred tax assets other comprehensive earnings tax effect period increase decrease. + References No definition available. + Details
Name: | mlm_AccumulatedOtherComprehensiveLossNoncurrentDeferredTaxAssetsOtherComprehensiveEarningsTaxEffectPeriodIncreaseDecrease
Namespace Prefix: | mlm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Accumulated other comprehensive loss, noncurrent deferred tax assets, other comprehensive earnings, tax effect, unamortized value of terminated forward starting interest rate swap. + References No definition available. + Details
Name: | mlm_AccumulatedOtherComprehensiveLossNoncurrentDeferredTaxAssetsOtherComprehensiveEarningsTaxEffectUnamortizedValueOfTerminatedForwardStartingInterestRateSwap
Namespace Prefix: | mlm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Accumulated other comprehensive loss, noncurrent deferred tax assets, pension and postretirement benefit plans. + References No definition available. + Details
Name: | mlm_AccumulatedOtherComprehensiveLossNoncurrentDeferredTaxAssetsPensionAndPostretirementBenefitPlans
Namespace Prefix: | mlm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Accumulated other comprehensive loss, noncurrent deferred tax assets, unamortized value of terminated forward starting interest rate swap. + References No definition available. + Details
Name: | mlm_AccumulatedOtherComprehensiveLossNoncurrentDeferredTaxAssetsUnamortizedValueOfTerminatedForwardStartingInterestRateSwap
Namespace Prefix: | mlm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_EquityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration