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Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2016	May 02, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q1
Trading Symbol	MLM
Entity Registrant Name	MARTIN MARIETTA MATERIALS INC
Entity Central Index Key	0000916076
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		63,527,166

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Current Assets:
Cash and cash equivalents	$ 27,242	$ 168,409	$ 56,366
Accounts receivable, net	448,048	410,921	381,389
Inventories, net	485,367	469,141	505,047
Other current assets	37,658	33,164	103,027
Total Current Assets	998,315	1,081,635	1,045,829
Property, plant and equipment	5,778,368	5,613,198	5,694,546
Allowances for depreciation, depletion and amortization	(2,515,387)	(2,457,198)	(2,329,440)
Net property, plant and equipment	3,262,981	3,156,000	3,365,106
Goodwill	2,135,295	2,068,235	2,071,471
Other noncurrent assets	142,281	141,189	102,959
Total Assets	7,058,287	6,957,611	7,177,319
Current Liabilities:
Bank overdraft		10,235
Accounts payable	174,398	164,718	184,066
Accrued salaries, benefits and payroll taxes	17,052	30,939	23,590
Pension and postretirement benefits	9,169	8,168	6,637
Accrued insurance and other taxes	52,501	62,781	58,742
Current maturities of long-term debt and short-term facilities	177,430	18,713	13,873
Accrued interest	23,004	16,156	22,461
Other current liabilities	38,577	54,948	33,653
Total Current Liabilities	492,131	366,658	343,022
Long-term debt	1,575,327	1,550,061	1,562,190
Pension, postretirement and postemployment benefits	226,924	224,538	252,923
Deferred income taxes, net	620,569	583,459	518,360
Other noncurrent liabilities	197,700	172,718	158,641
Total Liabilities	3,112,651	2,897,434	2,835,136
Equity:
Common stock, par value $0.01 per share	633	643	673
Preferred stock, par value $0.01 per share
Additional paid-in capital	3,302,258	3,287,827	3,255,809
Accumulated other comprehensive loss	(103,833)	(105,622)	(106,723)
Retained earnings	743,593	874,436	1,190,807
Total Shareholders' Equity	3,942,651	4,057,284	4,340,566
Noncontrolling interests	2,985	2,893	1,617
Total Equity	3,945,636	4,060,177	4,342,183
Total Liabilities and Equity	7,058,287	6,957,611	7,177,319
Operating Permits
Current Assets:
Intangibles, net	444,148	444,725	497,841
Other Intangible Assets
Current Assets:
Intangibles, net	$ 75,267	$ 65,827	$ 94,113

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Preferred stock, par value	$ 0.01	$ 0.01	$ 0.01

Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Net Sales	$ 733,960	$ 631,876
Freight and delivery revenues	54,774	59,471
Total revenues	788,734	691,347
Cost of sales	589,326	557,615
Freight and delivery costs	54,774	59,471
Total cost of revenues	644,100	617,086
Gross Profit	144,634	74,261
Selling, general & administrative expenses	59,861	49,450
Acquisition-related expenses, net	425	1,604
Other operating expenses and (income), net	579	(2,364)
Earnings from Operations	83,769	25,571
Interest expense	20,034	19,331
Other nonoperating (income) and expenses, net	(1,030)	893
Earnings before taxes on income	64,765	5,347
Taxes on income	19,710	(812)
Consolidated net earnings	45,055	6,159
Less: Net earnings attributable to noncontrolling interests	61	33
Net Earnings Attributable to Martin Marietta Materials, Inc.	44,994	6,126
Consolidated Comprehensive Earnings: (See Note 1)
Earnings attributable to Martin Marietta Materials, Inc.	46,783	5,562
Earnings attributable to noncontrolling interests	92	35
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 46,875	$ 5,597
Net Earnings Attributable to Martin Marietta Materials, Inc. per common share
Basic attributable to common shareholders	$ 0.70	$ 0.07
Diluted attributable to common shareholders	$ 0.69	$ 0.07
Weighted-Average Common Shares Outstanding:
Basic	64,158	67,411
Diluted	64,350	67,676
Cash Dividends Per Common Share	$ 0.40	$ 0.40

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash Flows from Operating Activities:
Consolidated net earnings	$ 45,055	$ 6,159
Adjustments to reconcile consolidated net earnings to net cash provided by operating activities:
Depreciation, depletion and amortization	68,410	67,268
Stock-based compensation expense	7,228	2,907
Gain on divestitures and sales of assets	(100)	(1,576)
Deferred income taxes	17,988	27,774
Excess tax benefits from stock-based compensation transactions	(1,278)	(109)
Other items, net	(2,036)	1,192
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable, net	(29,695)	40,006
Inventories, net	(13,495)	(19,071)
Accounts payable	9,231	(20,328)
Other assets and liabilities, net	(34,300)	(69,097)
Net Cash Provided by Operating Activities	67,008	35,125
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(94,228)	(56,085)
Acquisitions, net	(123,000)	(10,589)
Cash received in acquisition	3,446
Proceeds from divestitures and sales of assets	3,415	1,475
Repayments from affiliate		1,808
Net Cash Used for Investing Activities	(210,367)	(63,391)
Cash Flows from Financing Activities:
Borrowings of debt	210,000
Repayments of debt	(26,390)	(4,738)
Payments on capital lease obligations	(780)	(795)
Change in bank overdraft	(10,235)	(183)
Dividends paid	(25,847)	(28,354)
Issuances of common stock	4,166	9,942
Repurchases of common stock	(150,000)
Excess tax benefits from stock-based compensation transactions	1,278	109
Net Cash Provided by (Used for) Financing Activities	2,192	(24,019)
Net Decrease in Cash and Cash Equivalents	(141,167)	(52,285)
Cash and Cash Equivalents, beginning of period	168,409	108,651
Cash and Cash Equivalents, end of period	27,242	56,366
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest	11,394	11,417
Cash paid for income taxes	$ 10,721	$ 18,678

Consolidated Statement of Total Equity - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Total Shareholders' Equity	Noncontrolling Interests
Beginning Balance at Dec. 31, 2015	$ 4,060,177	$ 643	$ 3,287,827	$ (105,622)	$ 874,436	$ 4,057,284	$ 2,893
Beginning Balance (in shares) at Dec. 31, 2015		64,479,000
Consolidated net earnings	45,055				44,994	44,994	61
Other comprehensive (loss) earnings, net of tax	1,820			1,789		1,789	31
Dividends declared	(25,847)				(25,847)	(25,847)
Issuances of common stock for stock award plans	7,203		7,203			7,203
Issuances of common stock for stock award plans (in shares)		54,000
Repurchases of common stock	(150,000)	$ (10)			(149,990)	(150,000)
Repurchases of common stock, Shares		(1,028,000)
Stock-based compensation expense	7,228		7,228			7,228
Ending Balance at Mar. 31, 2016	$ 3,945,636	$ 633	$ 3,302,258	$ (103,833)	$ 743,593	$ 3,942,651	$ 2,985
Ending Balance (in shares) at Mar. 31, 2016		63,505,000

Significant Accounting Policies

3 Months Ended

Mar. 31, 2016

Accounting Policies [Abstract]

Significant Accounting Policies

1.	Significant Accounting Policies

Organization

Martin Marietta Materials, Inc. (the “Corporation” or “Martin Marietta”) is engaged principally in the construction aggregates business. The aggregates product line accounted for 55% of 2015 consolidated net sales and includes crushed stone, sand and gravel, and is used for construction of highways and other infrastructure projects, and in the nonresidential and residential construction industries. Aggregates products are also used in the railroad, agricultural, utility and environmental industries. These aggregates products, along with the Corporation’s aggregates-related downstream product lines, which accounted for 27% of 2015 consolidated net sales and include asphalt products, ready mixed concrete and road paving construction services, are sold and shipped from a network of more than 400 quarries, distribution facilities and plants in 26 states, Nova Scotia and the Bahamas. The aggregates and aggregates-related downstream product lines are reported collectively as the “Aggregates business”.

The Corporation currently conducts the Aggregates business through three reportable segments: the Mid-America Group, the Southeast Group and the West Group.

AGGREGATES BUSINESS

Reportable Segments

Mid-America Group

Southeast Group

West Group

Operating Locations

Indiana, Iowa,

northern Kansas, Kentucky, Maryland, Minnesota, Missouri,

eastern Nebraska, North Carolina, Ohio,

South Carolina,

Virginia, Washington and

West Virginia

Alabama, Florida, Georgia, Tennessee,
Nova Scotia and the Bahamas

Arkansas, Colorado, southern Kansas,

Louisiana, western Nebraska, Nevada, Oklahoma, Texas, Utah

and Wyoming

The Corporation has a Cement segment, which accounted for 11% of 2015 consolidated net sales. The Cement segment has production facilities located in Midlothian, Texas, south of Dallas/Fort Worth and Hunter, Texas, north of San Antonio. The Cement business produces Portland and specialty cements. Similar to the Aggregates business, cement is used in infrastructure projects, nonresidential and residential construction, and the railroad, agricultural, utility and environmental industries. The high calcium limestone reserves, used as a raw material, are owned by the Cement business and are adjacent to each of the plants.

The Corporation has a Magnesia Specialties segment with manufacturing facilities in Manistee, Michigan, and Woodville, Ohio. The Magnesia Specialties segment, which accounted for 7% of 2015 consolidated net sales, produces magnesia-based chemicals products used in industrial, agricultural and environmental applications and dolomitic lime sold primarily to customers in the steel industry.

1.	Significant Accounting Policies (continued)

Basis of Presentation

The accompanying unaudited consolidated financial statements of the Corporation have been prepared in accordance with generally accepted accounting principles for interim financial information and with the instructions to the Quarterly Report on Form 10-Q and in Article 10 of Regulation S-X. The Corporation has continued to follow the accounting policies set forth in the audited consolidated financial statements and related notes thereto included in the Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015. In the opinion of management, the interim consolidated financial information provided herein reflects all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the results of operations, financial position and cash flows for the interim periods. The consolidated results of operations for the three months ended March 31, 2016 are not indicative of the results expected for other interim periods or the full year. The consolidated balance sheet at December 31, 2015 has been derived from the audited consolidated financial statements at that date but does not include all of the information and notes required by generally accepted accounting principles for complete financial statements. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Corporation’s Annual Report on Form 10-K for the year ended December 31, 2015.

Debt Issuance Costs

The Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”), which amends the presentation of debt issuance costs in the financial statements. The ASU requires an entity to present debt issuance costs related to a recognized debt liability in the balance sheet as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts, and does not impact the recognition and measurement guidance for debt issuance costs. The Corporation adopted this ASU on January 1, 2016 and has retrospectively adjusted the prior periods presented, resulting in a reclassification of $3,588,000 and $4,427,000 from Other noncurrent assets to Long-term debt as of December 31, 2015 and March 31, 2015, respectively, and $533,000 from Other current assets to Current maturities of long-term debt and short-term maturities as of December 31, 2015 and March 31, 2015.

Revenue Recognition Standard

The FASB issued an accounting standard update that amends the accounting guidance on revenue recognition. The new standard intends to provide a more robust framework for addressing revenue issues, improve comparability of revenue recognition practices and improve disclosure requirements. The new standard is effective January 1, 2018 and can be applied on a full retrospective or modified retrospective approach. The Corporation is currently evaluating the impact the provisions of the new standard will have on its financial statements.

1.	Significant Accounting Policies (continued)

Lease Standard

In February 2016, the FASB issued a new accounting standard, Accounting Codification Standard 842 – Leases, intending to improve financial reporting of leases and to provide more transparency into off-balance sheet leasing obligations. The guidance requires virtually all leases, excluding mineral interest leases, to be recorded on the balance sheet and provides guidance on the recognition of lease expense and income. The new standard is effective January 1, 2019 and must be applied on a modified retrospective approach. The Corporation is currently evaluating the impact the new standard will have on its financial statements.

Share-based Payment Standard

In March 2016, the FASB issued ASU 2016-09, “Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting”, which simplifies certain aspects of accounting guidance and requirements for share-based transactions. The ASU is effective for reporting periods beginning January 1, 2017. The Corporation is evaluating the impact of the ASU on its financial statements.

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss

Consolidated comprehensive earnings/loss for the Corporation consist of consolidated net earnings or loss; adjustments for the funded status of pension and postretirement benefit plans; foreign currency translation adjustments; and the amortization of the value of terminated forward starting interest rate swap agreements into interest expense, and are presented in the Corporation’s consolidated statements of earnings and comprehensive earnings.

Comprehensive earnings attributable to Martin Marietta is as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	44,994	$	6,126
Other comprehensive earnings (loss), net of tax		1,789		(564	)
Comprehensive earnings attributable to Martin Marietta Materials, Inc.	$	46,783	$	5,562

1.	Significant Accounting Policies (continued)

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss

Comprehensive earnings attributable to noncontrolling interests, consisting of net earnings and adjustments for the funded status of pension and postretirement benefit plans, is as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Net earnings attributable to noncontrolling interests	$	61	$	33
Other comprehensive earnings, net of tax		31		2
Comprehensive earnings attributable to noncontrolling interests	$	92	$	35

Accumulated other comprehensive loss consists of unrealized gains and losses related to the funded status of pension and postretirement benefit plans; foreign currency translation; and the unamortized value of terminated forward starting interest rate swap agreements, and is presented on the Corporation’s consolidated balance sheets.

Changes in accumulated other comprehensive earnings (loss), net of tax, are as follows:

	(Dollars in Thousands)
							Unamortized
							Value of
							Terminated			Accumulated
	Pension and						Forward Starting			Other
	Postretirement			Foreign			Interest Rate			Comprehensive
	Benefit Plans			Currency			Swap			Loss
	Three Months Ended March 31, 2016
Balance at beginning of period	$	(103,380	)	$	(264	)	$	(1,978	)	$	(105,622	)
Other comprehensive earnings before reclassifications, net of tax		—			115			—			115
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,473			—			201			1,674
Other comprehensive earnings, net of tax		1,473			115			201			1,789
Balance at end of period	$	(101,907	)	$	(149	)	$	(1,777	)	$	(103,833	)

	Three Months Ended March 31, 2015
Balance at beginning of period	$	(106,688	)	$	3,278		$	(2,749	)	$	(106,159	)
Other comprehensive loss before reclassifications, net of tax		—			(2,288	)		—			(2,288	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,537			—			187			1,724
Other comprehensive earnings (loss), net of tax		1,537			(2,288	)		187			(564	)
Balance at end of period	$	(105,151	)	$	990		$	(2,562	)	$	(106,723	)

1.	Significant Accounting Policies (continued)

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss (continued)

Changes in net noncurrent deferred tax assets recorded in accumulated other comprehensive loss are as follows:

	(Dollars in Thousands)
	Pension and Postretirement Benefit Plans			Unamortized Value of Terminated Forward Starting Interest Rate Swap			Net Noncurrent Deferred Tax Assets

	Three Months Ended March 31, 2016
Balance at beginning of period	$	66,467		$	1,290		$	67,757
Tax effect of other comprehensive earnings		(944	)		(131	)		(1,075	)
Balance at end of period	$	65,523		$	1,159		$	66,682

	Three Months Ended March 31, 2015
Balance at beginning of period	$	68,568		$	1,799		$	70,367
Tax effect of other comprehensive earnings		(1,016	)		(120	)		(1,136	)
Balance at end of period	$	67,552		$	1,679		$	69,231

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Affected line items in the consolidated
	March 31,						statements of earnings and
	2016			2015			comprehensive earnings
	(Dollars in Thousands)
Pension and postretirement benefit plans
Settlement charge	$	59		$	—
Amortization of:
Prior service credit		(374	)		(471	)
Actuarial loss		2,732			3,024
		2,417			2,553		Cost of sales; Selling, general and administrative expenses
Tax benefit		(944	)		(1,016	)	Taxes on income
	$	1,473		$	1,537

Unamortized value of terminated forward starting interest rate swap
Additional interest expense	$	332		$	307		Interest expense
Tax benefit		(131	)		(120	)	Taxes on income
	$	201		$	187

1.	Significant Accounting Policies (continued)

Earnings per Common Share

The numerator for basic and diluted earnings per common share is net earnings attributable to Martin Marietta Materials, Inc. reduced by dividends and undistributed earnings attributable to the Corporation’s certain stock-based compensation. If there is a net loss, no amount of the undistributed loss is attributed to unvested participating securities. The denominator for basic earnings per common share is the weighted-average number of common shares outstanding during the period. Diluted earnings per common share are computed assuming that the weighted-average number of common shares is increased by the conversion, using the treasury stock method, of awards to be issued to employees and nonemployee members of the Corporation’s Board of Directors under certain stock-based compensation arrangements if the conversion is dilutive. For the three months ended March 31, 2016 and 2015, the diluted per-share computations reflect a change in the number of common shares outstanding to include the number of additional shares that would have been outstanding if the potentially dilutive common shares had been issued.

The following table reconciles the numerator and denominator for basic and diluted earnings per common share:

	Three Months Ended
	March 31,
	2016		2015
	(In Thousands)
Net earnings from continuing operations attributable to Martin Marietta Materials, Inc.	$	44,994	$	6,126
Less: Distributed and undistributed earnings attributable to unvested awards		298		1,369
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$	44,696	$	4,757

Basic weighted-average common shares outstanding		64,158		67,411
Effect of dilutive employee and director awards		192		265
Diluted weighted-average common shares outstanding		64,350		67,676

Page 1 of 46

Inventories, Net

3 Months Ended

Mar. 31, 2016

Inventory Disclosure [Abstract]

Inventories, Net

2.	Inventories, Net

	March 31,			December 31,			March 31,
	2016			2015			2015
	(Dollars in Thousands)
Finished products	$	443,470		$	433,649		$	428,783
Products in process and raw materials		59,761			55,194			70,558
Supplies and expendable parts		112,022			110,882			125,547
		615,253			599,725			624,888
Less: Allowances		(129,886	)		(130,584	)		(119,841	)
Total	$	485,367		$	469,141		$	505,047

Long-Term Debt

3 Months Ended

Mar. 31, 2016

Debt Disclosure [Abstract]

Long-Term Debt

3.	Long-Term Debt

	March 31,			December 31,			March 31,
	2016			2015			2015
	(Dollars in Thousands)
6.6% Senior Notes, due 2018	$	299,201		$	299,113		$	298,842
7% Debentures, due 2025		124,024			124,002			123,938
6.25% Senior Notes, due 2037		227,933			227,917			227,880
4.25 % Senior Notes, due 2024		394,843			394,690			394,304
Floating Rate Notes, due 2017, interest rate of 2.13%, 1.71% and 1.36% at March 31, 2016, December 31, 2015 and March 31, 2015, respectively		298,837			298,868			298,304
Term Loan Facility, due 2018, interest rate of 1.94%, 1.86% and 1.67% at March 31, 2016, December 31, 2015 and March 31, 2015, respectively		217,109			222,521			231,259
Revolving Facility, interest rate of 3.75%		30,000			—			—
Trade Receivable Facility, interest rate of 1.13% at March 31, 2016		159,925			—			—
Other notes		885			1,663			1,536
Total debt		1,752,757			1,568,774			1,576,063
Less: Current maturities		(177,430	)		(18,713	)		(13,873	)
Long-term debt	$	1,575,327		$	1,550,061		$	1,562,190

The Corporation, through a wholly-owned special-purpose subsidiary, has a $250,000,000 trade receivable securitization facility (the “Trade Receivable Facility”), which matures on September 30, 2016. The Trade Receivable Facility, with SunTrust Bank, Regions Bank, PNC Bank, N.A. and certain other lenders that may become a party to the facility from time to time, is backed by eligible trade receivables, as defined, and is limited to the lesser of the facility limit or the borrowing base, as defined, of $324,734,000, $282,258,000 and $280,101,000 at March 31, 2016, December 31, 2015 and March 31, 2015, respectively. These receivables are originated by the Corporation and then sold to the wholly-owned special-purpose subsidiary by the Corporation. The Corporation continues to be responsible for the servicing and administration of the receivables purchased by the wholly-owned special-purpose subsidiary. Borrowings under the Trade Receivable Facility bear interest at a rate equal to one-month LIBOR plus 0.7%. The Trade Receivable Facility contains a cross-default provision to the Corporation’s other debt agreements.

The Corporation’s Credit Agreement, which provides a $250,000,000 senior unsecured term loan (the “Term Loan Facility”) and a $350,000,000 five-year senior unsecured revolving facility (the “Revolving Facility”), requires the Corporation’s ratio of consolidated debt to consolidated earnings before interest, taxes, depreciation, depletion and amortization (“EBITDA”), as defined by the Credit Agreement, for the trailing twelve months (the “Ratio”) to not exceed 3.50x as of the end of any fiscal quarter, provided that the Corporation may exclude from the Ratio debt incurred in connection with certain acquisitions for a period of 180 days so long as the Corporation, as a consequence of such specified acquisition, does not have its rating on long-term unsecured debt fall below BBB by Standard & Poor’s or Baa2 by Moody’s and the Ratio calculated without such exclusion does not exceed 3.75x. Additionally, if no amounts are outstanding under both the Revolving Facility and the Trade Receivable Facility, consolidated debt, including debt for which the Corporation is a co-borrower, may be reduced by the Corporation’s unrestricted cash and cash equivalents in excess of $50,000,000, such reduction not to exceed $200,000,000, for purposes of the covenant calculation.

3.	Long-Term Debt (continued)

In accordance with the amended Credit Agreement, the Corporation adjusted consolidated EBITDA to add back any integration or similar costs or expenses related to the TXI business combination incurred in any period prior to the second anniversary of the closing of the TXI business combination, not to exceed $70,000,000. The Corporation was in compliance with this Ratio at March 31, 2016.

Available borrowings under the Revolving Facility are reduced by any outstanding letters of credit issued by the Corporation under the Revolving Facility. At March 31, 2016, December 31, 2015 and March 31, 2015, the Corporation had $2,507,000 of outstanding letters of credit issued under the Revolving Facility.

Current debt maturities consist of borrowings under the Trade Receivable Facility as well as the current portions of the Term Loan Facility and other notes. The increase in current debt maturities as of March 31, 2016 is attributable to the balance drawn on the Trade Receivable Facility.

On April 5, 2016, the Corporation repaid the $30,000,000 outstanding on the Revolving Facility.

Accumulated other comprehensive loss includes the unamortized value of terminated forward starting interest rate swap agreements. For the three months ended March 31, 2016 and 2015, the Corporation recognized $332,000 and $307,000, respectively, as additional interest expense. The ongoing amortization of the terminated value of the forward starting interest rate swap agreements will increase annual interest expense by approximately $1,400,000 until the maturity of the 6.6% Senior Notes in 2018.

Financial Instruments

3 Months Ended

Mar. 31, 2016

Financial Instruments Disclosure [Abstract]

Financial Instruments

4.	Financial Instruments

The Corporation’s financial instruments include cash equivalents, accounts receivable, notes receivable, bank overdraft, accounts payable, publicly-registered long-term notes, debentures and other long-term debt.

Cash equivalents are placed primarily in money market funds, money market demand deposit accounts and Eurodollar time deposits. The Corporation’s cash equivalents have original maturities of less than three months. Due to the short maturity of these investments, they are carried on the consolidated balance sheets at cost, which approximates fair value.

Accounts receivable are due from a large number of customers, primarily in the construction industry, and are dispersed across wide geographic and economic regions. However, accounts receivable are more heavily concentrated in certain states (namely, Texas, Colorado, North Carolina, Iowa and Georgia). The estimated fair values of accounts receivable approximate their carrying amounts due to the short-term nature of the receivables.

Notes receivable are not publicly traded. Management estimates that the fair value of notes receivable approximates the carrying amount due to the short-term nature of the receivables.

The bank overdraft represents amounts to be funded to financial institutions for checks that have cleared the bank. The estimated fair value of the bank overdraft approximates its carrying value due to the short-term nature of the overdraft.

Accounts payable represent amounts owed to suppliers and vendors. The estimated fair value of accounts payable approximates its carrying amount due to the short-term nature of the payables.

4.	Financial Instruments (continued)

The carrying values and fair values of the Corporation’s long-term debt were $1,752,757,000 and $1,817,950,000, respectively, at March 31, 2016; $1,568,774,000 and $1,625,193,000, respectively, at December 31, 2015; and $1,576,063,000 and $1,691,478,000, respectively, at March 31, 2015. The estimated fair value of the publicly-registered long-term notes was estimated based on Level 1 of the fair value hierarchy using quoted market prices. The estimated fair value of other borrowings, which primarily represents variable-rate debt, was based on Level 2 of the fair value hierarchy using quoted market prices for similar debt instruments, and approximates their carrying amounts as the interest rates reset periodically.

Income Taxes

3 Months Ended

Mar. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

5.	Income Taxes

The Corporation’s effective income tax rate for the three months ended March 31, 2016 was 30.4%. The estimated effective income tax rates reflect the effect of federal and state income taxes and the impact of differences in book and tax accounting arising from the net permanent benefits associated with the statutory depletion deduction for mineral reserves and the domestic production deduction. For the three months ended March 31, 2015, there was an income tax benefit which reflects the exercise of converted stock awards issued to former TXI personnel.

The Corporation records interest accrued in relation to unrecognized tax benefits as income tax expense. Penalties, if incurred, are recorded as operating expenses in the consolidated statements of earnings and comprehensive earnings.

Pension and Postretirement Benefits

3 Months Ended

Mar. 31, 2016

Compensation And Retirement Disclosure [Abstract]

Pension and Postretirement Benefits

6.	Pension and Postretirement Benefits

The estimated components of the recorded net periodic benefit cost (credit) for pension and postretirement benefits are as follows:

	Three Months Ended March 31,
	Pension						Postretirement Benefits
	2016			2015			2016			2015
	(Dollars in Thousands)
Service cost	$	5,507		$	6,290		$	34		$	39
Interest cost		8,871			8,112			238			230
Expected return on assets		(9,434	)		(9,104	)		—			—
Amortization of:
Prior service cost (credit)		88			105			(462	)		(576	)
Actuarial loss (gain)		2,831			3,108			(99	)		(82	)
Settlement charge		59			—			—			—
Special termination benefit		126			256			—			—
Net periodic benefit cost (credit)	$	8,048		$	8,767		$	(289	)	$	(389	)

Commitments and Contingencies

3 Months Ended

Mar. 31, 2016

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

7.	Commitments and Contingencies

Legal and Administrative Proceedings

The Corporation is engaged in certain legal and administrative proceedings incidental to its normal business activities. In the opinion of management and counsel, based upon currently-available facts, it is remote that the ultimate outcome of any litigation and other proceedings, including those pertaining to environmental matters, relating to the Corporation and its subsidiaries, will have a material adverse effect on the overall results of the Corporation’s operations, its cash flows or its financial position.

Borrowing Arrangements with Affiliate

The Corporation is a co-borrower with an unconsolidated affiliate for a $25,000,000 revolving line of credit agreement with BB&T Bank. The affiliate has agreed to reimburse and indemnify the Corporation for any payments and expenses the Corporation may incur from this agreement. The Corporation holds a lien on the affiliate’s membership interest in a joint venture as collateral for payment under the revolving line of credit.

In addition, the Corporation has a $6,000,000 outstanding loan due from this unconsolidated affiliate as of March 31, 2016, December 31, 2015 and March 31, 2015.

Employees

Approximately 10% of the Corporation’s employees are represented by a labor union. All such employees are hourly employees. The Corporation maintains collective bargaining agreements relating to the union employees with the Aggregates business and Magnesia Specialties segments. For the Magnesia Specialties segment located in Manistee, Michigan and Woodville, Ohio, 100% of its hourly employees are represented by labor unions. The Manistee collective bargaining agreement expires in August 2019, and the Woodville collective bargaining agreement expires in May 2018.

Business Segments

3 Months Ended

Mar. 31, 2016

Segment Reporting [Abstract]

Business Segments

8.	Business Segments

The Aggregates business contains three reportable business segments: Mid-America Group, Southeast Group and West Group. The Corporation also has Cement and Magnesia Specialties segments. Corporate loss from operations primarily includes depreciation on capitalized interest, expenses for certain corporate administrative functions, business development and integration expenses, unallocated corporate expenses and other nonrecurring and/or non-operational adjustments. Intersegment sales represent net sales from one segment to another segment.

8.	Business Segments (Continued)

The following tables display selected financial data for continuing operations for the Corporation’s reportable business segments. Total revenues and net sales in the table below, as well as the consolidated statements of earnings and comprehensive earnings, exclude intersegment sales, which are eliminated.

	Three Months Ended
	March 31,
	2016			2015
	(Dollars in Thousands)
Total revenues:
Mid-America Group	$	186,347		$	140,834
Southeast Group		71,671			64,678
West Group		392,995			320,571
Total Aggregates Business		651,013			526,083
Cement		73,551			102,100
Magnesia Specialties		64,170			63,164
Total	$	788,734		$	691,347

Net sales:
Mid-America Group	$	173,372		$	129,705
Southeast Group		67,284			59,770
West Group		363,926			287,082
Total Aggregates Business		604,582			476,557
Cement		69,873			96,565
Magnesia Specialties		59,505			58,754
Total	$	733,960		$	631,876

Earnings (Loss) from operations:
Mid-America Group	$	14,424		$	(4,203	)
Southeast Group		6,971			(1,548	)
West Group		38,797			14,499
Total Aggregates Business		60,192			8,748
Cement		26,316			12,229
Magnesia Specialties		20,563			17,789
Corporate		(23,302	)		(13,195	)
Total	$	83,769		$	25,571

The decline in the Cement business’s net sales is attributable to the California cement operations, included in the three months ended March 31, 2015 and divested as of September 30, 2015. For the three months ended March 31, 2015, total revenues, net sales and loss from operations for the California cement operations were $33,759,000, $32,511,000 and $7,421,000, respectively.

8.	Business Segments (continued)

Cement intersegment sales, which are to the aggregates and ready mixed concrete product lines in the West Group, were $27,147,000 and $18,377,000 for the three months ended March 31, 2016 and 2015, respectively.

The Aggregates business includes the aggregates product line and aggregates-related downstream product lines, which include asphalt, ready mixed concrete and road paving product lines. All aggregates-related downstream product lines reside in the West Group. The following tables, which are reconciled to consolidated amounts, provide net sales and gross profit by line of business: Aggregates (further divided by product line), Cement and Magnesia Specialties.

	Three Months Ended
	March 31,
	2016			2015
	(Dollars in Thousands)
Net sales:
Aggregates	$	406,439		$	332,214
Asphalt		3,875			9,645
Ready Mixed Concrete		186,785			127,572
Road Paving		7,483			7,126
Total Aggregates Business		604,582			476,557
Cement		69,873			96,565
Magnesia Specialties		59,505			58,754
Total	$	733,960		$	631,876

Gross profit (loss):
Aggregates	$	81,083		$	41,417
Asphalt		(2,269	)		(1,463	)
Ready Mixed Concrete		18,086			2,084
Road Paving		(3,894	)		(3,311	)
Total Aggregates Business		93,006			38,727
Cement		32,556			18,985
Magnesia Specialties		22,970			20,178
Corporate		(3,898	)		(3,629	)
Total	$	144,634		$	74,261

For the three months ended March 31, 2015, gross loss for the California cement operations was $4,046,000.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

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+ Details

Supplemental Cash Flow Information

3 Months Ended

Mar. 31, 2016

Supplemental Cash Flow Elements [Abstract]

Supplemental Cash Flow Information

9.	Supplemental Cash Flow Information

The components of the change in other assets and liabilities, net, are as follows:

	Three Months Ended
	March 31,
	2016			2015
	(Dollars in Thousands)
Other current and noncurrent assets	$	(2,089	)	$	(4,083	)
Accrued salaries, benefits and payroll taxes		(12,951	)		(13,703	)
Accrued insurance and other taxes		(10,280	)		386
Accrued income taxes		(8,473	)		(46,700	)
Accrued pension, postretirement and postemployment benefits		5,775			5,830
Other current and noncurrent liabilities		(6,282	)		(10,827	)
	$	(34,300	)	$	(69,097	)

The change in accrued insurance and other taxes is attributable to certain property tax payments for tax year 2015 made in January 2016. These property taxes for tax year 2014 were paid prior to in 2014. The change in accrued income taxes is attributable to an increase in income tax expense in the current year.

Noncash investing and financing activities are as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Noncash investing and financing activities:
Acquisition of assets through capital lease	$	—	$	1,222
Acquisition of assets through asset exchange		—		5,153

Business Combination	3 Months Ended
Business Combination	Mar. 31, 2016
Business Combinations [Abstract]
Business Combination	10.Business Combination During the quarter ended March 31, 2016, the Corporation acquired the outstanding stock of Rocky Mountain Materials and Asphalt, Inc., and Rocky Mountain Premix Inc. The acquisition provides more than 500 million tons of mineral reserves and expands the Corporation’s presence along the Front Range of the Rocky Mountains, home to 80% of Colorado’s population. The acquired operations are reported through the West Group. The Corporation has recorded preliminary fair values of the assets acquired and liabilities assumed; however, certain amounts are subject to change as additional reviews are performed, including asset and liability verification. Specific accounts subject to ongoing purchase accounting include property, plant and equipment; goodwill; other intangible assets; deferred income taxes and accrued expenses. The acquisition was not financially material and therefore pro forma information is not required.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

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+ Details

Stock-Based Compensation	3 Months Ended
Stock-Based Compensation	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	11. Stock-Based Compensation During the quarter ended March 31, 2016, the Corporation awarded its annual grant of stock-based compensation, which included 75,421 of performance stock units and 68,720 of restricted stock units. The grant-date fair value of each award is $142.02 for the performance stock units and $124.41 for the restricted stock units. No stock options are expected to be awarded in 2016. In past years, annual stock-based compensation awards were primarily made in the second quarter of the year. The change in the composition of the awards and the timing of the annual grant resulted in higher expense recorded in the first quarter compared with prior years. For the quarters ended March 31, 2016 and 2015, stock-based compensation expense was $7,228,000 and $2,907,000, respectively.

Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2016

Accounting Policies [Abstract]

Organization

The Corporation currently conducts the Aggregates business through three reportable segments: the Mid-America Group, the Southeast Group and the West Group.

AGGREGATES BUSINESS

Reportable Segments

Mid-America Group

Southeast Group

West Group

Operating Locations

Indiana, Iowa,

northern Kansas, Kentucky, Maryland, Minnesota, Missouri,

eastern Nebraska, North Carolina, Ohio,

South Carolina,

Virginia, Washington and

West Virginia

Alabama, Florida, Georgia, Tennessee,
Nova Scotia and the Bahamas

Arkansas, Colorado, southern Kansas,

Louisiana, western Nebraska, Nevada, Oklahoma, Texas, Utah

and Wyoming

Basis of Presentation

Debt Issuance Cost, Revenue Recognition Standard, Lease Standard and Share-based Payment Standard

Debt Issuance Costs

Revenue Recognition Standard

1.	Significant Accounting Policies (continued)

Lease Standard

Share-based Payment Standard

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss

Comprehensive earnings attributable to Martin Marietta is as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	44,994	$	6,126
Other comprehensive earnings (loss), net of tax		1,789		(564	)
Comprehensive earnings attributable to Martin Marietta Materials, Inc.	$	46,783	$	5,562

1.	Significant Accounting Policies (continued)

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss

Comprehensive earnings attributable to noncontrolling interests, consisting of net earnings and adjustments for the funded status of pension and postretirement benefit plans, is as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Net earnings attributable to noncontrolling interests	$	61	$	33
Other comprehensive earnings, net of tax		31		2
Comprehensive earnings attributable to noncontrolling interests	$	92	$	35

Changes in accumulated other comprehensive earnings (loss), net of tax, are as follows:

	(Dollars in Thousands)
							Unamortized
							Value of
							Terminated			Accumulated
	Pension and						Forward Starting			Other
	Postretirement			Foreign			Interest Rate			Comprehensive
	Benefit Plans			Currency			Swap			Loss
	Three Months Ended March 31, 2016
Balance at beginning of period	$	(103,380	)	$	(264	)	$	(1,978	)	$	(105,622	)
Other comprehensive earnings before reclassifications, net of tax		—			115			—			115
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,473			—			201			1,674
Other comprehensive earnings, net of tax		1,473			115			201			1,789
Balance at end of period	$	(101,907	)	$	(149	)	$	(1,777	)	$	(103,833	)

	Three Months Ended March 31, 2015
Balance at beginning of period	$	(106,688	)	$	3,278		$	(2,749	)	$	(106,159	)
Other comprehensive loss before reclassifications, net of tax		—			(2,288	)		—			(2,288	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,537			—			187			1,724
Other comprehensive earnings (loss), net of tax		1,537			(2,288	)		187			(564	)
Balance at end of period	$	(105,151	)	$	990		$	(2,562	)	$	(106,723	)

1.	Significant Accounting Policies (continued)

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss (continued)

Changes in net noncurrent deferred tax assets recorded in accumulated other comprehensive loss are as follows:

	(Dollars in Thousands)
	Pension and Postretirement Benefit Plans			Unamortized Value of Terminated Forward Starting Interest Rate Swap			Net Noncurrent Deferred Tax Assets

	Three Months Ended March 31, 2016
Balance at beginning of period	$	66,467		$	1,290		$	67,757
Tax effect of other comprehensive earnings		(944	)		(131	)		(1,075	)
Balance at end of period	$	65,523		$	1,159		$	66,682

	Three Months Ended March 31, 2015
Balance at beginning of period	$	68,568		$	1,799		$	70,367
Tax effect of other comprehensive earnings		(1,016	)		(120	)		(1,136	)
Balance at end of period	$	67,552		$	1,679		$	69,231

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Affected line items in the consolidated
	March 31,						statements of earnings and
	2016			2015			comprehensive earnings
	(Dollars in Thousands)
Pension and postretirement benefit plans
Settlement charge	$	59		$	—
Amortization of:
Prior service credit		(374	)		(471	)
Actuarial loss		2,732			3,024
		2,417			2,553		Cost of sales; Selling, general and administrative expenses
Tax benefit		(944	)		(1,016	)	Taxes on income
	$	1,473		$	1,537

Unamortized value of terminated forward starting interest rate swap
Additional interest expense	$	332		$	307		Interest expense
Tax benefit		(131	)		(120	)	Taxes on income
	$	201		$	187

Earnings (Loss) per Common Share

1.	Significant Accounting Policies (continued)

Earnings per Common Share

The following table reconciles the numerator and denominator for basic and diluted earnings per common share:

	Three Months Ended
	March 31,
	2016		2015
	(In Thousands)
Net earnings from continuing operations attributable to Martin Marietta Materials, Inc.	$	44,994	$	6,126
Less: Distributed and undistributed earnings attributable to unvested awards		298		1,369
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$	44,696	$	4,757

Basic weighted-average common shares outstanding		64,158		67,411
Effect of dilutive employee and director awards		192		265
Diluted weighted-average common shares outstanding		64,350		67,676

Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2016

Significant Accounting Policies [Line Items]

Changes in Accumulated Other Comprehensive Earnings (Loss), Net of Tax

Changes in accumulated other comprehensive earnings (loss), net of tax, are as follows:

	(Dollars in Thousands)
							Unamortized
							Value of
							Terminated			Accumulated
	Pension and						Forward Starting			Other
	Postretirement			Foreign			Interest Rate			Comprehensive
	Benefit Plans			Currency			Swap			Loss
	Three Months Ended March 31, 2016
Balance at beginning of period	$	(103,380	)	$	(264	)	$	(1,978	)	$	(105,622	)
Other comprehensive earnings before reclassifications, net of tax		—			115			—			115
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,473			—			201			1,674
Other comprehensive earnings, net of tax		1,473			115			201			1,789
Balance at end of period	$	(101,907	)	$	(149	)	$	(1,777	)	$	(103,833	)

	Three Months Ended March 31, 2015
Balance at beginning of period	$	(106,688	)	$	3,278		$	(2,749	)	$	(106,159	)
Other comprehensive loss before reclassifications, net of tax		—			(2,288	)		—			(2,288	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,537			—			187			1,724
Other comprehensive earnings (loss), net of tax		1,537			(2,288	)		187			(564	)
Balance at end of period	$	(105,151	)	$	990		$	(2,562	)	$	(106,723	)

Noncurrent Deferred Tax Assets Recorded In Accumulated Other Comprehensive Loss

1.	Significant Accounting Policies (continued)

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss (continued)

Changes in net noncurrent deferred tax assets recorded in accumulated other comprehensive loss are as follows:

	(Dollars in Thousands)
	Pension and Postretirement Benefit Plans			Unamortized Value of Terminated Forward Starting Interest Rate Swap			Net Noncurrent Deferred Tax Assets

	Three Months Ended March 31, 2016
Balance at beginning of period	$	66,467		$	1,290		$	67,757
Tax effect of other comprehensive earnings		(944	)		(131	)		(1,075	)
Balance at end of period	$	65,523		$	1,159		$	66,682

	Three Months Ended March 31, 2015
Balance at beginning of period	$	68,568		$	1,799		$	70,367
Tax effect of other comprehensive earnings		(1,016	)		(120	)		(1,136	)
Balance at end of period	$	67,552		$	1,679		$	69,231

Reclassification Out of Accumulated Other Comprehensive Loss

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Affected line items in the consolidated
	March 31,						statements of earnings and
	2016			2015			comprehensive earnings
	(Dollars in Thousands)
Pension and postretirement benefit plans
Settlement charge	$	59		$	—
Amortization of:
Prior service credit		(374	)		(471	)
Actuarial loss		2,732			3,024
		2,417			2,553		Cost of sales; Selling, general and administrative expenses
Tax benefit		(944	)		(1,016	)	Taxes on income
	$	1,473		$	1,537

Unamortized value of terminated forward starting interest rate swap
Additional interest expense	$	332		$	307		Interest expense
Tax benefit		(131	)		(120	)	Taxes on income
	$	201		$	187

Basic and Diluted Earnings (Loss) per Common Share

The following table reconciles the numerator and denominator for basic and diluted earnings per common share:

	Three Months Ended
	March 31,
	2016		2015
	(In Thousands)
Net earnings from continuing operations attributable to Martin Marietta Materials, Inc.	$	44,994	$	6,126
Less: Distributed and undistributed earnings attributable to unvested awards		298		1,369
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$	44,696	$	4,757

Basic weighted-average common shares outstanding		64,158		67,411
Effect of dilutive employee and director awards		192		265
Diluted weighted-average common shares outstanding		64,350		67,676

Parent

Significant Accounting Policies [Line Items]

Comprehensive Earnings

Comprehensive earnings attributable to Martin Marietta is as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	44,994	$	6,126
Other comprehensive earnings (loss), net of tax		1,789		(564	)
Comprehensive earnings attributable to Martin Marietta Materials, Inc.	$	46,783	$	5,562

Noncontrolling Interests

Significant Accounting Policies [Line Items]

Comprehensive Earnings

1.	Significant Accounting Policies (continued)

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss

Comprehensive earnings attributable to noncontrolling interests, consisting of net earnings and adjustments for the funded status of pension and postretirement benefit plans, is as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Net earnings attributable to noncontrolling interests	$	61	$	33
Other comprehensive earnings, net of tax		31		2
Comprehensive earnings attributable to noncontrolling interests	$	92	$	35

Inventories, Net (Tables)

3 Months Ended

Mar. 31, 2016

Inventory Disclosure [Abstract]

Schedule of Inventories Net

	March 31,			December 31,			March 31,
	2016			2015			2015
	(Dollars in Thousands)
Finished products	$	443,470		$	433,649		$	428,783
Products in process and raw materials		59,761			55,194			70,558
Supplies and expendable parts		112,022			110,882			125,547
		615,253			599,725			624,888
Less: Allowances		(129,886	)		(130,584	)		(119,841	)
Total	$	485,367		$	469,141		$	505,047

Long-Term Debt (Tables)

3 Months Ended

Mar. 31, 2016

Debt Disclosure [Abstract]

Long-Term Debt

	March 31,			December 31,			March 31,
	2016			2015			2015
	(Dollars in Thousands)
6.6% Senior Notes, due 2018	$	299,201		$	299,113		$	298,842
7% Debentures, due 2025		124,024			124,002			123,938
6.25% Senior Notes, due 2037		227,933			227,917			227,880
4.25 % Senior Notes, due 2024		394,843			394,690			394,304
Floating Rate Notes, due 2017, interest rate of 2.13%, 1.71% and 1.36% at March 31, 2016, December 31, 2015 and March 31, 2015, respectively		298,837			298,868			298,304
Term Loan Facility, due 2018, interest rate of 1.94%, 1.86% and 1.67% at March 31, 2016, December 31, 2015 and March 31, 2015, respectively		217,109			222,521			231,259
Revolving Facility, interest rate of 3.75%		30,000			—			—
Trade Receivable Facility, interest rate of 1.13% at March 31, 2016		159,925			—			—
Other notes		885			1,663			1,536
Total debt		1,752,757			1,568,774			1,576,063
Less: Current maturities		(177,430	)		(18,713	)		(13,873	)
Long-term debt	$	1,575,327		$	1,550,061		$	1,562,190

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ 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)
-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 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: 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=34725769&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 9: 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

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

+ Details

Pension and Postretirement Benefits (Tables)

3 Months Ended

Mar. 31, 2016

Compensation And Retirement Disclosure [Abstract]

Schedule of Components of Net Periodic Benefit Cost

The estimated components of the recorded net periodic benefit cost (credit) for pension and postretirement benefits are as follows:

	Three Months Ended March 31,
	Pension						Postretirement Benefits
	2016			2015			2016			2015
	(Dollars in Thousands)
Service cost	$	5,507		$	6,290		$	34		$	39
Interest cost		8,871			8,112			238			230
Expected return on assets		(9,434	)		(9,104	)		—			—
Amortization of:
Prior service cost (credit)		88			105			(462	)		(576	)
Actuarial loss (gain)		2,831			3,108			(99	)		(82	)
Settlement charge		59			—			—			—
Special termination benefit		126			256			—			—
Net periodic benefit cost (credit)	$	8,048		$	8,767		$	(289	)	$	(389	)

Business Segments (Tables)

3 Months Ended

Mar. 31, 2016

Segment Reporting [Abstract]

Financial Data for Continuing Operation For Corporation's Reportable Business Segments

	Three Months Ended
	March 31,
	2016			2015
	(Dollars in Thousands)
Total revenues:
Mid-America Group	$	186,347		$	140,834
Southeast Group		71,671			64,678
West Group		392,995			320,571
Total Aggregates Business		651,013			526,083
Cement		73,551			102,100
Magnesia Specialties		64,170			63,164
Total	$	788,734		$	691,347

Net sales:
Mid-America Group	$	173,372		$	129,705
Southeast Group		67,284			59,770
West Group		363,926			287,082
Total Aggregates Business		604,582			476,557
Cement		69,873			96,565
Magnesia Specialties		59,505			58,754
Total	$	733,960		$	631,876

Earnings (Loss) from operations:
Mid-America Group	$	14,424		$	(4,203	)
Southeast Group		6,971			(1,548	)
West Group		38,797			14,499
Total Aggregates Business		60,192			8,748
Cement		26,316			12,229
Magnesia Specialties		20,563			17,789
Corporate		(23,302	)		(13,195	)
Total	$	83,769		$	25,571

Net Sales By Product Line

	Three Months Ended
	March 31,
	2016			2015
	(Dollars in Thousands)
Net sales:
Aggregates	$	406,439		$	332,214
Asphalt		3,875			9,645
Ready Mixed Concrete		186,785			127,572
Road Paving		7,483			7,126
Total Aggregates Business		604,582			476,557
Cement		69,873			96,565
Magnesia Specialties		59,505			58,754
Total	$	733,960		$	631,876

Gross profit (loss):
Aggregates	$	81,083		$	41,417
Asphalt		(2,269	)		(1,463	)
Ready Mixed Concrete		18,086			2,084
Road Paving		(3,894	)		(3,311	)
Total Aggregates Business		93,006			38,727
Cement		32,556			18,985
Magnesia Specialties		22,970			20,178
Corporate		(3,898	)		(3,629	)
Total	$	144,634		$	74,261

Supplemental Cash Flow Information (Tables)

3 Months Ended

Mar. 31, 2016

Supplemental Cash Flow Elements [Abstract]

Components of Change in Other Assets and Liabilities, Net

The components of the change in other assets and liabilities, net, are as follows:

	Three Months Ended
	March 31,
	2016			2015
	(Dollars in Thousands)
Other current and noncurrent assets	$	(2,089	)	$	(4,083	)
Accrued salaries, benefits and payroll taxes		(12,951	)		(13,703	)
Accrued insurance and other taxes		(10,280	)		386
Accrued income taxes		(8,473	)		(46,700	)
Accrued pension, postretirement and postemployment benefits		5,775			5,830
Other current and noncurrent liabilities		(6,282	)		(10,827	)
	$	(34,300	)	$	(69,097	)

Schedule Of Noncash Investing and Financing Activities

Noncash investing and financing activities are as follows:

	Three Months Ended
	March 31,
	2016		2015
	(Dollars in Thousands)
Noncash investing and financing activities:
Acquisition of assets through capital lease	$	—	$	1,222
Acquisition of assets through asset exchange		—		5,153

Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2016 Facility State Segment	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($)
Significant Accounting Policies [Line Items]
Number of quarries distribution facilities and plants \| Facility	400
Number of states with aggregates business sales by destination \| State	26
Number of reportable segments \| Segment	3
Restatement Adjustment \| Other Noncurrent Assets
Significant Accounting Policies [Line Items]
Debt issuance cost		$ 3,588,000	$ 4,427,000
Restatement Adjustment \| Other Current Assets
Significant Accounting Policies [Line Items]
Debt issuance cost		$ 533,000	$ 533,000
Product Concentration Risk \| Sales Revenue Segment \| Cement
Significant Accounting Policies [Line Items]
Total net sales, percentage		11.00%
Product Concentration Risk \| Sales Revenue Segment \| Magnesia Specialties
Significant Accounting Policies [Line Items]
Total net sales, percentage		7.00%
Aggregates Product Line \| Product Concentration Risk \| Product Line Sales
Significant Accounting Policies [Line Items]
Total net sales, percentage		55.00%
Aggregates-Related Downstream Product Lines \| Product Concentration Risk \| Product Line Sales
Significant Accounting Policies [Line Items]
Total net sales, percentage		27.00%

Comprehensive Earnings Attributable to Martin Marietta Materials Incorporated (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net earnings attributable to Martin Marietta Materials, Inc.	$ 44,994	$ 6,126
Other comprehensive earnings (loss), net of tax	1,789	(564)
Earnings attributable to Martin Marietta Materials, Inc.	$ 46,783	$ 5,562

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Comprehensive Earnings Attributable to Noncontrolling Interests (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net earnings attributable to noncontrolling interests	$ 61	$ 33
Other comprehensive earnings, net of tax	31	2
Comprehensive earnings attributable to noncontrolling interests	$ 92	$ 35

Changes in Accumulated Other Comprehensive Earnings (Loss), Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (105,622)	$ (106,159)
Other comprehensive earnings (loss) before reclassifications, net of tax	115	(2,288)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	1,674	1,724
Other comprehensive earnings (loss), net of tax	1,789	(564)
Balance at end of period	(103,833)	(106,723)
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(103,380)	(106,688)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	1,473	1,537
Other comprehensive earnings (loss), net of tax	1,473	1,537
Balance at end of period	(101,907)	(105,151)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(264)	3,278
Other comprehensive earnings (loss) before reclassifications, net of tax	115	(2,288)
Other comprehensive earnings (loss), net of tax	115	(2,288)
Balance at end of period	(149)	990
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(1,978)	(2,749)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	201	187
Other comprehensive earnings (loss), net of tax	201	187
Balance at end of period	$ (1,777)	$ (2,562)

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Equity [Abstract]
Balance at beginning of period, Pension and Postretirement Benefit Plans	$ 66,467	$ 68,568
Other comprehensive earnings, tax effect, Pension and Postretirement Benefit Plans	(944)	(1,016)
Balance at end of period, Pension and Postretirement Benefit Plans	65,523	67,552
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	1,290	1,799
Other comprehensive earnings, tax effect, Unamortized Value of Terminated Forward Starting Interest Rate Swap	(131)	(120)
Balance at end of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	1,159	1,679
Balance at beginning of period, Net Non current Deferred Tax Assets	67,757	70,367
Other comprehensive earnings, tax effect, Net Non current Deferred Tax Assets	(1,075)	(1,136)
Balance at end of period, Net Non current Deferred Tax Assets	$ 66,682	$ 69,231

Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 20,034	$ 19,331
Earnings from Continuing Operations	1,674	1,724
Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	1,473	1,537
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	201	187
Reclassification out of Accumulated Other Comprehensive Income \| Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Settlement charge	59
Prior service credit	(374)	(471)
Actuarial loss	2,732	3,024
Income tax benefit	(944)	(1,016)
Earnings from Continuing Operations	1,473	1,537
Reclassification out of Accumulated Other Comprehensive Income \| Pension and Postretirement Benefit Plans \| Cost of sale; Selling, General & Administrative Expenses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications out of accumulated other comprehensive loss before taxes	2,417	2,553
Reclassification out of Accumulated Other Comprehensive Income \| Unamortized Value of Terminated Forward Starting Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	332	307
Income tax benefit	(131)	(120)
Earnings from Continuing Operations	$ 201	$ 187

Basic and Diluted Earnings Per Common Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net earnings from continuing operations attributable to Martin Marietta Materials, Inc.	$ 44,994	$ 6,126
Less: Distributed and undistributed earnings attributable to unvested awards	298	1,369
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$ 44,696	$ 4,757
Basic weighted-average common shares outstanding	64,158	67,411
Effect of dilutive employee and director awards	192	265
Diluted weighted-average common shares outstanding	64,350	67,676

Inventories Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Inventory Disclosure [Abstract]
Finished products	$ 443,470	$ 433,649	$ 428,783
Products in process and raw materials	59,761	55,194	70,558
Supplies and expendable parts	112,022	110,882	125,547
Inventories, Gross	615,253	599,725	624,888
Less: Allowances	(129,886)	(130,584)	(119,841)
Total	$ 485,367	$ 469,141	$ 505,047

Long-Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Debt Instrument [Line Items]
Total debt	$ 1,752,757	$ 1,568,774	$ 1,576,063
Less: Current maturities	(177,430)	(18,713)	(13,873)
Long-term debt	1,575,327	1,550,061	1,562,190
Revolving Facility
Debt Instrument [Line Items]
Total debt	30,000
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Total debt	299,201	299,113	298,842
7% Debentures, Due 2025
Debt Instrument [Line Items]
Total debt	124,024	124,002	123,938
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Total debt	227,933	227,917	227,880
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total debt	394,843	394,690	394,304
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Total debt	298,837	298,868	298,304
Term Loan Facility, Due 2018
Debt Instrument [Line Items]
Total debt	217,109	222,521	231,259
Trade Receivable Facility
Debt Instrument [Line Items]
Total debt	159,925
Other Notes
Debt Instrument [Line Items]
Total debt	$ 885	$ 1,663	$ 1,536

Long-Term Debt (Parenthetical) (Detail)	3 Months Ended
Long-Term Debt (Parenthetical) (Detail)	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Revolving Facility
Debt Instrument [Line Items]
Credit Facility interest rate	3.75%
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	2.13%	1.71%	1.36%
Term Loan Facility, Due 2018
Debt Instrument [Line Items]
Maturity date	2018
Interest rate	1.94%	1.86%	1.67%
Trade Receivable Facility
Debt Instrument [Line Items]
Credit Facility interest rate	1.13%

Long-Term Debt - Additional information (Detail) - USD ($)		3 Months Ended		12 Months Ended
	Apr. 05, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2015
Debt Instrument [Line Items]
Maximum consolidated debt reduction for unrestricted cash and cash equivalents for debt covenant calculation		$ 200,000,000
Additional interest expense		332,000	$ 307,000
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
Excluding Acquisition Bridge Debt \| Maximum
Debt Instrument [Line Items]
Debt covenant		3.75
Revolving Facility
Debt Instrument [Line Items]
Credit facility commitment		$ 350,000,000
Senior unsecured revolving facility, maturity period		5 years
Outstanding letters of credit		$ 2,507,000	2,507,000		$ 2,507,000
Revolving Facility \| Subsequent Event
Debt Instrument [Line Items]
Repayment of outstanding revolving facility	$ 30,000,000
Trade Receivable Facility
Debt Instrument [Line Items]
Credit facility commitment		$ 250,000,000
Debt instrument maturity period		Sep. 30, 2016
Credit facility borrowing base		$ 324,734,000	$ 280,101,000		$ 282,258,000
Trade Receivable Facility \| London Interbank Offered Rate(LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		0.70%
Term Loan Facility
Debt Instrument [Line Items]
Credit facility commitment		$ 250,000,000
Amended \| Maximum \| Texas Industries Inc.
Debt Instrument [Line Items]
Acquisition integration expenses				$ 70,000,000
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Interest rate on notes		6.60%
Maturity date		2018
Increase in annual interest expense due to ongoing amortization of the terminated value of the swap agreements		$ 1,400,000

Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Long-term debt, carrying values	$ 1,752,757	$ 1,568,774	$ 1,576,063
Long-term debt, fair values	$ 1,817,950	$ 1,625,193	$ 1,691,478

Income Taxes - Additional Information (Detail)	3 Months Ended
Income Taxes - Additional Information (Detail)	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	30.40%

Schedule of Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5,507	$ 6,290
Interest cost	8,871	8,112
Expected return on assets	(9,434)	(9,104)
Prior service cost (credit)	88	105
Actuarial loss (gain)	2,831	3,108
Settlement charge	59
Special termination benefit	126	256
Net periodic benefit cost (credit)	8,048	8,767
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	34	39
Interest cost	238	230
Prior service cost (credit)	(462)	(576)
Actuarial loss (gain)	(99)	(82)
Net periodic benefit cost (credit)	$ (289)	$ (389)

Commitments and Contingencies - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Commitments and Contingencies [Line Items]
Guarantee of affiliate's obligations	$ 25,000,000
Due from affiliate	$ 6,000,000	$ 6,000,000	$ 6,000,000
Percentage of employees represented in labor union	10.00%
Woodville
Commitments and Contingencies [Line Items]
Collective bargaining agreement expiration month year	2018-05
Magnesia Specialties
Commitments and Contingencies [Line Items]
Percentage of employees represented in labor union	100.00%
Collective bargaining agreement expiration month year	2019-08

Business Segments - Additional Information (Detail)	3 Months Ended
Business Segments - Additional Information (Detail)	Mar. 31, 2016 USD ($) Segment	Mar. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Reportable business segments \| Segment	3
Total revenues	$ 788,734,000	$ 691,347,000
Net Sales	733,960,000	631,876,000
Earnings (Loss) from Operations	83,769,000	25,571,000
Gross profit (loss)	144,634,000	74,261,000
Operating Segments \| Cement
Segment Reporting Information [Line Items]
Total revenues	73,551,000	102,100,000
Net Sales	69,873,000	96,565,000
Earnings (Loss) from Operations	26,316,000	12,229,000
Operating Segments \| Cement \| California
Segment Reporting Information [Line Items]
Total revenues		33,759,000
Net Sales		32,511,000
Earnings (Loss) from Operations		7,421,000
Gross profit (loss)		(4,046,000)
Intersegment Eliminations \| Cement
Segment Reporting Information [Line Items]
Total revenues	$ 27,147,000	$ 18,377,000

Financial Data for Continuing Operations for Corporations Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Total revenues	$ 788,734	$ 691,347
Net Sales	733,960	631,876
Earnings (Loss) from Operations	83,769	25,571
Aggregates Business
Segment Reporting Information [Line Items]
Total revenues	651,013	526,083
Net Sales	604,582	476,557
Earnings (Loss) from Operations	60,192	8,748
Operating Segments \| Mid-America Group \| Aggregates Business
Segment Reporting Information [Line Items]
Total revenues	186,347	140,834
Net Sales	173,372	129,705
Earnings (Loss) from Operations	14,424	(4,203)
Operating Segments \| Southeast Group \| Aggregates Business
Segment Reporting Information [Line Items]
Total revenues	71,671	64,678
Net Sales	67,284	59,770
Earnings (Loss) from Operations	6,971	(1,548)
Operating Segments \| West Group \| Aggregates Business
Segment Reporting Information [Line Items]
Total revenues	392,995	320,571
Net Sales	363,926	287,082
Earnings (Loss) from Operations	38,797	14,499
Operating Segments \| Cement
Segment Reporting Information [Line Items]
Total revenues	73,551	102,100
Net Sales	69,873	96,565
Earnings (Loss) from Operations	26,316	12,229
Operating Segments \| Magnesia Specialties
Segment Reporting Information [Line Items]
Total revenues	64,170	63,164
Net Sales	59,505	58,754
Earnings (Loss) from Operations	20,563	17,789
Corporate
Segment Reporting Information [Line Items]
Earnings (Loss) from Operations	$ (23,302)	$ (13,195)

Net Sales and Gross Profit by Line of Business (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Product Information [Line Items]
Net Sales	$ 733,960	$ 631,876
Gross profit (loss), Total	144,634	74,261
Corporate
Product Information [Line Items]
Gross profit (loss), Total	(3,898)	(3,629)
Aggregates
Product Information [Line Items]
Net Sales	406,439	332,214
Gross profit (loss), Total	81,083	41,417
Asphalt
Product Information [Line Items]
Net Sales	3,875	9,645
Gross profit (loss), Total	(2,269)	(1,463)
Ready Mixed Concrete
Product Information [Line Items]
Net Sales	186,785	127,572
Gross profit (loss), Total	18,086	2,084
Road Paving
Product Information [Line Items]
Net Sales	7,483	7,126
Gross profit (loss), Total	(3,894)	(3,311)
Aggregates Business
Product Information [Line Items]
Net Sales	604,582	476,557
Gross profit (loss), Total	93,006	38,727
Cement
Product Information [Line Items]
Net Sales	69,873	96,565
Gross profit (loss), Total	32,556	18,985
Magnesia Specialties
Product Information [Line Items]
Net Sales	59,505	58,754
Gross profit (loss), Total	$ 22,970	$ 20,178

Components of Change in Other Assets and Liabilities Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Other current and noncurrent assets	$ (2,089)	$ (4,083)
Accrued salaries, benefits and payroll taxes	(12,951)	(13,703)
Accrued insurance and other taxes	(10,280)	386
Accrued income taxes	(8,473)	(46,700)
Accrued pension, postretirement and postemployment benefits	5,775	5,830
Other current and noncurrent liabilities	(6,282)	(10,827)
Change in other assets and liabilities	$ (34,300)	$ (69,097)

Noncash Investing and Financing Activities (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2015 USD ($)
Supplemental Cash Flow Elements [Abstract]
Acquisition of assets through capital lease	$ 1,222
Acquisition of assets through asset exchange	$ 5,153

Business Combination - Additional Information (Detail)	3 Months Ended
Business Combination - Additional Information (Detail)	Mar. 31, 2016 T
Colorado \| Minimum
Business Combinations [Line Items]
Acquisition of mineral reserves	500,000,000

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 7,228	$ 2,907
Performance Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of awards, granted	75,421
Weighted average grant-date fair value of stock awards, granted	$ 142.02
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of awards, granted	68,720
Weighted average grant-date fair value of stock awards, granted	$ 124.41
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options expected to be awarded	0