Stock-Based Compensation - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014 Age	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options issued to former option holders	821,282
Non-qualified stock options received by nonemployee board of directors	3,000
Weighted-average grant-date exercise price of options granted	$ 121.00	$ 108.24	$ 69.12
Aggregate intrinsic values of options exercised	$ 9,709	$ 7,142	$ 7,176
Aggregate intrinsic values for options outstanding	23,806
Aggregate intrinsic values for options exercisable	21,954
Common stock price	$ 110.32mlm_CommonStockPrice
Percentage of incentive compensation to acquire shares, maximum	50.00%
Percentage of discount rate to market value on the incentive compensation	20.00%
Company normal retirement age	62mlm_CompanyNormalRetirementAge
Awards available for grant	2,152,000
Common stock reserved for future issuance	250,000
Cumulative shares issued under shareholder value achievement plan	42,025
Recognized tax benefit related to stock-based compensation expense	3,542	2,772	3,077
Incentive Compensation Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock price	$ 110.32
Weighted-average grant-date fair value of stock awards, granted	$ 109.17	$ 99.23	$ 81.41
Aggregate intrinsic values for stock awards	801
Aggregate intrinsic values of stock awards, distributed	584	466	375
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of stock awards, granted	$ 126.88	$ 108.24	$ 69.12
Aggregate intrinsic values for stock awards	37,025
Aggregate intrinsic values of stock awards, distributed	$ 3,555	$ 9,413	$ 8,695
Directors' Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	300,000
Minimum percentage of board of directors retainer required to be paid in common stock	20.00%
Percentage of discount rate to market value on board of directors fees paid in common stock	20.00%
Common stock issued under the plan	3,804	6,583	9,502
Texas Industries Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options issued to former option holders	821,282
Number of options issued per single option	0.7
Employee stock options expiration period	90 days
Options granted in 2014 and 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	10 years
Options granted prior to 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	8 years
Options granted prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	10 years

Business acquisition equity interest number of option issued per single option.

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Common stock price.

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Company normal retirement age.

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Cumulative shares issued under shareholder value achievement plan.

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Minimum percentage of directors retainer required to be paid in common stock.

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Non-qualified stock options received by non-employee directors.

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Percentage of discount rate to market value on directors fees paid in common stock.

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Percentage Of Discount Rate To The Market Value On The Incentive Compensation

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Percentage of incentive compensation to acquire shares maximum.

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Share based compensation arrangement by share based payment award options replacement in period.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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Intrinsic value of equity-based compensation awards vested. Excludes stock and unit options.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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- Definition

Number of share instruments newly issued under a share-based compensation plan.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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