View Filing Data

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2017	Jul. 26, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q2
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		62,839,694

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Current Assets:
Cash and cash equivalents	$ 36,722	$ 50,038	$ 28,596
Accounts receivable, net	570,618	457,910	534,459
Inventories, net	549,865	521,624	504,877
Other current assets	87,092	56,813	53,997
Total Current Assets	1,244,297	1,086,385	1,121,929
Property, plant and equipment	6,306,083	6,115,530	5,896,512
Allowances for depreciation, depletion and amortization	(2,800,823)	(2,692,135)	(2,574,307)
Net property, plant and equipment	3,505,260	3,423,395	3,322,205
Goodwill	2,160,060	2,159,337	2,136,783
Operating permits, net	437,713	442,202	442,349
Other intangibles, net	65,526	69,110	64,327
Other noncurrent assets	103,004	120,476	145,712
Total Assets	7,515,860	7,300,905	7,233,305
Current Liabilities:
Bank overdraft	3,794		7,143
Accounts payable	187,227	178,598	197,733
Accrued salaries, benefits and payroll taxes	36,202	47,428	24,864
Pension and postretirement benefits	8,802	9,293	9,120
Accrued insurance and other taxes	59,958	60,093	62,525
Current maturities of long-term debt and short-term facilities	140,037	180,036	238,155
Other current liabilities	98,305	71,140	62,064
Total Current Liabilities	534,325	546,588	601,604
Long-term debt	1,641,944	1,506,153	1,541,062
Pension, postretirement and postemployment benefits	253,908	248,086	236,562
Deferred income taxes, net	663,414	663,019	639,776
Other noncurrent liabilities	221,738	194,469	197,801
Total Liabilities	3,315,329	3,158,315	3,216,805
Equity:
Common stock, par value $0.01 per share	627	630	633
Preferred stock, par value $0.01 per share
Additional paid-in capital	3,355,992	3,334,461	3,318,859
Accumulated other comprehensive loss	(125,906)	(130,687)	(106,068)
Retained earnings	967,058	935,574	800,028
Total Shareholders' Equity	4,197,771	4,139,978	4,013,452
Noncontrolling interests	2,760	2,612	3,048
Total Equity	4,200,531	4,142,590	4,016,500
Total Liabilities and Equity	$ 7,515,860	$ 7,300,905	$ 7,233,305

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
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 (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net Sales	$ 996,289	$ 915,436	$ 1,787,973	$ 1,649,396
Freight and delivery revenues	67,235	61,862	119,410	116,636
Total revenues	1,063,524	977,298	1,907,383	1,766,032
Cost of sales	722,195	668,005	1,366,813	1,256,715
Freight and delivery costs	67,235	61,862	119,410	116,636
Total cost of revenues	789,430	729,867	1,486,223	1,373,351
Gross Profit	274,094	247,431	421,160	392,681
Selling, general & administrative expenses	68,373	59,781	137,908	118,130
Acquisition-related expenses, net	1,982	248	2,004	547
Other operating income, net	(9,113)	(3,446)	(8,754)	(2,868)
Earnings from Operations	212,852	190,848	290,002	276,872
Interest expense	24,045	20,294	44,896	40,328
Other nonoperating income, net	(5,420)	(4,994)	(5,956)	(3,770)
Earnings before taxes on income	194,227	175,548	251,062	240,314
Taxes on income	51,986	53,435	66,514	73,145
Consolidated net earnings	142,241	122,113	184,548	167,169
Less: Net (loss) earnings attributable to noncontrolling interests	(38)	61	(65)	122
Net Earnings Attributable to Martin Marietta Materials, Inc.	142,279	122,052	184,613	167,047
Consolidated Comprehensive Earnings: (See Note 1)
Earnings attributable to Martin Marietta Materials, Inc.	144,798	119,817	189,394	166,601
(Loss) Earnings attributable to noncontrolling interests	(37)	63	(63)	155
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 144,761	$ 119,880	$ 189,331	$ 166,756
Net Earnings Attributable to Martin Marietta Materials, Inc. Per Common Share:
Basic attributable to common shareholders	$ 2.26	$ 1.91	$ 2.92	$ 2.61
Diluted attributable to common shareholders	$ 2.25	$ 1.90	$ 2.91	$ 2.60
Weighted-Average Common Shares Outstanding:
Basic	62,858	63,532	62,961	63,845
Diluted	63,141	63,802	63,246	64,091
Cash Dividends Per Common Share	$ 0.42	$ 0.40	$ 0.84	$ 0.80

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows from Operating Activities:
Consolidated net earnings	$ 184,548	$ 167,169
Adjustments to reconcile consolidated net earnings to net cash provided by operating activities:
Depreciation, depletion and amortization	146,102	139,617
Stock-based compensation expense	17,727	12,801
Gain on divestitures and sales of assets	(17,514)	(261)
Deferred income taxes	2,464	34,389
Other items, net	(4,393)	(5,767)
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable, net	(112,708)	(117,524)
Inventories, net	(28,240)	(33,131)
Accounts payable	11,663	32,521
Other assets and liabilities, net	29,950	(19,970)
Net Cash Provided by Operating Activities	229,599	209,844
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(216,089)	(210,559)
Acquisitions, net	(2,200)	(123,000)
Cash received in acquisition		3,446
Proceeds from divestitures and sales of assets	32,089	4,474
Payment of railcar construction advances	(40,930)
Reimbursement of railcar construction advances	40,930
Net Cash Used for Investing Activities	(186,200)	(325,639)
Cash Flows from Financing Activities:
Borrowings of debt	941,244	280,000
Repayments of debt	(845,023)	(70,420)
Payments on capital lease obligations	(1,752)	(1,563)
Debt issuance costs	(1,055)
Change in bank overdraft	3,795	(3,092)
Contributions by owners of noncontrolling interest	211
Dividends paid	(53,135)	(51,467)
Proceeds from exercise of stock options	7,937	18,070
Shares withheld for employees' income tax obligations	(8,938)	(5,546)
Repurchases of common stock	(99,999)	(190,000)
Net Cash Used for Financing Activities	(56,715)	(24,018)
Net Decrease in Cash and Cash Equivalents	(13,316)	(139,813)
Cash and Cash Equivalents, beginning of period	50,038	168,409
Cash and Cash Equivalents, end of period	$ 36,722	$ 28,596

Consolidated Statement of Total Equity (Unaudited) - USD ($) shares in Thousands, $ 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				$ (105,622)
Consolidated net earnings (loss)	$ 167,169
Ending Balance at Jun. 30, 2016	4,016,500			(106,068)
Beginning Balance at Mar. 31, 2016				(103,833)
Consolidated net earnings (loss)	122,113
Ending Balance at Jun. 30, 2016	4,016,500			(106,068)
Beginning Balance at Dec. 31, 2016	4,142,590	$ 630	$ 3,334,461	(130,687)	$ 935,574	$ 4,139,978	$ 2,612
Beginning Balance (in shares) at Dec. 31, 2016		63,176
Consolidated net earnings (loss)	184,548				184,613	184,613	(65)
Other comprehensive earnings, net of tax	4,783			4,781		4,781	2
Dividends declared	(53,135)				(53,135)	(53,135)
Issuances of common stock for stock award plans	3,806	$ 2	3,804			3,806
Issuances of common stock for stock award plans (in shares)		122
Repurchases of common stock	(99,999)	$ (5)			(99,994)	(99,999)
Repurchases of common stock, Shares		(458)
Stock-based compensation expense	17,727		17,727			17,727
Contributions by owners of noncontrolling interest	211						211
Ending Balance at Jun. 30, 2017	4,200,531	$ 627	3,355,992	(125,906)	967,058	4,197,771	2,760
Ending Balance (in shares) at Jun. 30, 2017		62,840
Beginning Balance at Mar. 31, 2017				(128,425)
Consolidated net earnings (loss)	142,241
Ending Balance at Jun. 30, 2017	$ 4,200,531	$ 627	$ 3,355,992	$ (125,906)	$ 967,058	$ 4,197,771	$ 2,760
Ending Balance (in shares) at Jun. 30, 2017		62,840

Significant Accounting Policies

6 Months Ended

Jun. 30, 2017

Accounting Policies [Abstract]

Significant Accounting Policies

1.	Significant Accounting Policies

Organization

Martin Marietta Materials, Inc. (the Company or Martin Marietta) is engaged principally in the building materials business, including aggregates, cement, ready mixed concrete and asphalt and paving product lines, collectively reported as the Building Materials business. The aggregates product line is sold and shipped from a network of more than 270 quarries and distribution facilities in 26 states, Nova Scotia and the Bahamas. The cement, ready mixed concrete and asphalt and paving product lines are located in strategic, vertically integrated markets, predominately Texas and Colorado. Building materials are used for construction of highways and other infrastructure projects, and in the nonresidential and residential construction industries. Aggregates and cement products are also used in the railroad, agricultural, utility and environmental industries.

Effective January 1, 2017, the Company reorganized the operations and management reporting structure of its Texas-based aggregates, cement and ready mixed concrete product lines, resulting in a change to its reportable segments. As a result, the cement product line is reported in the West Group. The Company’s Building Materials business includes three reportable segments: the Mid-America Group, the Southeast Group and the West Group.

BUILDING MATERIALS 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

Product Lines	Aggregates	Aggregates	Aggregates, cement, ready mixed concrete and asphalt and paving

Products and Services	Crushed stone, sand and gravel	Crushed stone, sand and gravel	Crushed stone, sand and gravel; Portland and specialty cements; ready mixed concrete and asphalt and paving

The Company has a Magnesia Specialties segment with manufacturing facilities in Manistee, Michigan, and Woodville, Ohio. The Magnesia Specialties segment 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 Company 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. Other than the adoption of two new accounting standards described below, the Company has continued to follow the accounting policies set forth in the audited consolidated financial statements and related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. In the opinion of management, the interim consolidated financial information provided herein reflects all adjustments, consisting of normal recurring accruals, necessary for a fair statement of the results of operations, financial position and cash flows for the interim periods. The consolidated results of operations for the six months ended June 30, 2017 are not indicative of the results expected for other interim periods or the full year. The consolidated balance sheet at December 31, 2016 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 Company’s Annual Report on Form 10-K for the year ended December 31, 2016.

New Accounting Pronouncements

Share-Based Payment Accounting

Effective January 1, 2017, the Company adopted Accounting Standards Update (ASU) 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (ASU 2016-09), which simplifies certain aspects of accounting guidance and requirements for share-based transactions. ASU 2016-09 requires shares withheld for employees’ income tax obligations to be presented as a financing activity in the statement of cash flows, with retrospective presentation. For the six-months ended June 30, 2016, the Company reclassified $2,525,000 from operating activities to financing activities on the statement of cash flows. Additionally, excess tax benefits from stock-based compensation transactions are presented as an operating activity with retrospective presentation. The Company previously presented excess tax benefits from stock-based compensation transactions as a financing activity and, for the six-months ended June 30, 2016, reclassified $3,948,000 to operating activities on the statement of cash flows. ASU 2016-09 also requires excess tax benefits and tax deficiencies to be recognized prospectively as income tax benefits or expense in the period awards vest or are exercised. For the three- and six-months ended June 30, 2017, the Company recognized excess tax benefits of $2,989,000 and $5,259,000, respectively.

1.	Significant Accounting Policies (continued)

New Accounting Pronouncements

Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

In March 2017, the Financial Accounting Standards Board (FASB) issued ASU 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (ASU 2017-07), which revises the financial statement presentation for periodic pension and postretirement expense or credit, other than service cost. ASU 2017-07 requires net periodic benefit cost or credit, with the exception of service cost, to be presented retrospectively as nonoperating expense. As permitted by ASU 2017-07, the Company used the pension and other postretirement benefit plan disclosures for the prior comparative periods as a practical expedient to estimate amounts for retrospective application. Service cost will remain a component of earnings from operations and represent the only cost of pension and postretirement expense eligible for capitalization, notably in the Company’s inventory standards. The Company early adopted this standard effective January 1, 2017. For the three-months ended June 30, 2016, the Company reclassified $730,000, $1,728,000 and $648,000 from cost of sales; selling, general and administrative expenses; and other operating income and expenses, respectively, to nonoperating expense. For the six-months ended June 30, 2016, the Company reclassified $1,346,000, $3,240,000 and $774,000 from cost of sales; selling, general and administrative expenses; and other operating income and expenses, respectively, to nonoperating expense.

Pending Accounting Pronouncements

Revenue Recognition Standard

The FASB issued an accounting standards 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 Company has completed its initial assessment of the provisions of the new standard and, at this time, does not expect the impact to be material to its results of operations and expects to adopt using the full retrospective approach.

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 Company is currently assessing the impact of the updated standard on the Company’s financial statements. The Company believes the updated standard will have a material effect on its balance sheet but has not quantified the impact at this time.

Reclassifications

Prior-year information has been reclassified to conform to the presentation of the Company’s current reportable segments and for the adoption of the two accounting pronouncements aforementioned.

1.	Significant Accounting Policies (continued)

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss

Consolidated comprehensive earnings/loss and accumulated other comprehensive loss 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 Company’s consolidated statements of earnings and comprehensive earnings.

Comprehensive earnings attributable to Martin Marietta is as follows:

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2017		2016			2017		2016
	(Dollars in Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	142,279	$	122,052		$	184,613	$	167,047
Other comprehensive earnings (loss), net of tax		2,519		(2,235	)		4,781		(446	)
Comprehensive earnings attributable to Martin Marietta Materials, Inc.	$	144,798	$	119,817		$	189,394	$	166,601

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					Six Months Ended
	June 30,					June 30,
	2017			2016		2017			2016
	(Dollars in Thousands)
Net (loss) earnings attributable to noncontrolling interests	$	(38	)	$	61	$	(65	)	$	122
Other comprehensive earnings, net of tax		1			2		2			33
Comprehensive (loss) earnings attributable to noncontrolling interests	$	(37	)	$	63	$	(63	)	$	155

1.	Significant Accounting Policies (continued)

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

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 June 30, 2017
Balance at beginning of period	$	(126,463	)	$	(1,025	)	$	(937	)	$	(128,425	)
Other comprehensive earnings before reclassifications, net of tax		—			389			—			389
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,910			—			220			2,130
Other comprehensive earnings, net of tax		1,910			389			220			2,519
Balance at end of period	$	(124,553	)	$	(636	)	$	(717	)	$	(125,906	)

	Three Months Ended June 30, 2016
Balance at beginning of period	$	(101,907	)	$	(149	)	$	(1,777	)	$	(103,833	)
Other comprehensive loss before reclassifications, net of tax		(3,736	)		(232	)		—			(3,968	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,529			—			204			1,733
Other comprehensive (loss) earnings, net of tax		(2,207	)		(232	)		204			(2,235	)
Balance at end of period	$	(104,114	)	$	(381	)	$	(1,573	)	$	(106,068	)

1.	Significant Accounting Policies (continued)

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

	(Dollars in Thousands)
							Unamortized
							Value of
							Terminated			Accumulated
	Pension and						Forward Starting			Other
	Postretirement			Foreign			Interest Rate			Comprehensive
	Benefit Plans			Currency			Swap			Loss
	Six Months Ended June 30, 2017
Balance at beginning of period	$	(128,373	)	$	(1,162	)	$	(1,152	)	$	(130,687	)
Other comprehensive earnings before reclassifications, net of tax		—			526			—			526
Amounts reclassified from accumulated other comprehensive earnings, net of tax		3,820			—			435			4,255
Other comprehensive earnings, net of tax		3,820			526			435			4,781
Balance at end of period	$	(124,553	)	$	(636	)	$	(717	)	$	(125,906	)

	Six Months Ended June 30, 2016
Balance at beginning of period	$	(103,380	)	$	(264	)	$	(1,978	)	$	(105,622	)
Other comprehensive loss before reclassifications, net of tax		(3,830	)		(117	)		—			(3,947	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		3,096			—			405			3,501
Other comprehensive (loss) earnings, net of tax		(734	)		(117	)		405			(446	)
Balance at end of period	$	(104,114	)	$	(381	)	$	(1,573	)	$	(106,068	)

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 June 30, 2017
Balance at beginning of period	$	80,859		$	608		$	81,467
Tax effect of other comprehensive earnings		(1,184	)		(144	)		(1,328	)
Balance at end of period	$	79,675		$	464		$	80,139

	Three Months Ended June 30, 2016
Balance at beginning of period	$	65,523		$	1,159		$	66,682
Tax effect of other comprehensive earnings		1,408			(136	)		1,272
Balance at end of period	$	66,931		$	1,023		$	67,954

	Six Months Ended June 30, 2017
Balance at beginning of period	$	82,044		$	749		$	82,793
Tax effect of other comprehensive earnings		(2,369	)		(285	)		(2,654	)
Balance at end of period	$	79,675		$	464		$	80,139

	Six Months Ended June 30, 2016
Balance at beginning of period	$	66,467		$	1,290		$	67,757
Tax effect of other comprehensive earnings		464			(267	)		197
Balance at end of period	$	66,931		$	1,023		$	67,954

1.	Significant Accounting Policies (continued)

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

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Six Months Ended						Affected line items in the consolidated
	June 30,						June 30,						statements of earnings and
	2017			2016			2017			2016			comprehensive earnings
	(Dollars in Thousands)
Pension and postretirement benefit plans
Settlement charge	$	—		$	—		$	—		$	59
Amortization of:
Prior service credit		(358	)		(518	)		(716	)		(806	)
Actuarial loss		3,452			3,007			6,905			5,787
		3,094			2,489			6,189			5,040		Nonoperating expenses
Tax benefit		(1,184	)		(960	)		(2,369	)		(1,944	)	Taxes on income
	$	1,910		$	1,529		$	3,820		$	3,096

Unamortized value of terminated forward starting interest rate swap
Additional interest expense	$	364		$	340		$	720		$	672		Interest expense
Tax benefit		(144	)		(136	)		(285	)		(267	)	Taxes on income
	$	220		$	204		$	435		$	405

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 certain of the Company’s 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 Company’s Board of Directors under certain stock-based compensation arrangements if the conversion is dilutive. For the three and six months ended June 30, 2017 and 2016, 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.

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				Six Months Ended
	June 30,				June 30,
	2017		2016		2017		2016
	(In Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	142,279	$	122,052	$	184,613	$	167,047
Less: Distributed and undistributed earnings attributable to unvested awards		413		519		553		730
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$	141,866	$	121,533	$	184,060	$	166,317

Basic weighted-average common shares outstanding		62,858		63,532		62,961		63,845
Effect of dilutive employee and director awards		283		270		285		246
Diluted weighted-average common shares outstanding		63,141		63,802		63,246		64,091

Goodwill

6 Months Ended

Jun. 30, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill

	(In Thousands)
	Mid-America		Southeast		West
	Group		Group		Group		Total
Balance at January 1, 2017	$	281,403	$	50,346	$	1,827,588	$	2,159,337
Adjustments to purchase price allocations		—		—		723		723
Balance at June 30, 2017	$	281,403	$	50,346	$	1,828,311	$	2,160,060

The prior-year information has been reclassified to conform to the presentation of the Company’s current reportable segments.

Inventories, Net

6 Months Ended

Jun. 30, 2017

Inventory Disclosure [Abstract]

Inventories, Net

3.	Inventories, Net

	June 30,			December 31,			June 30,
	2017			2016			2016
	(Dollars in Thousands)
Finished products	$	508,144		$	479,291		$	463,807
Products in process and raw materials		59,410			61,171			60,324
Supplies and expendable parts		120,594			116,024			113,110
		688,148			656,486			637,241
Less: Allowances		(138,283	)		(134,862	)		(132,364	)
Total	$	549,865		$	521,624		$	504,877

Long-Term Debt

6 Months Ended

Jun. 30, 2017

Debt Disclosure [Abstract]

Long-Term Debt

4.	Long-Term Debt

	June 30,			December 31,			June 30,
	2017			2016			2016
	(Dollars in Thousands)
6.6% Senior Notes, due 2018	$	299,676		$	299,483		$	299,294
7% Debentures, due 2025		124,134			124,090			124,046
6.25% Senior Notes, due 2037		228,003			227,975			227,947
4.25% Senior Notes, due 2024		395,532			395,252			394,977
3.45% Senior Notes, due 2027		296,456			—			—
Floating Rate Notes, due 2020, interest rate of 1.82% at June 30, 2017		297,847			—			—
Floating Rate Notes, due 2017, interest rate of 2.10% and 1.73% at December 31, 2016 and June 30, 2016, respectively		—			299,033			298,793
Term Loan Facility, due 2018, interest rate of 1.96% at June 30, 2016		—			—			213,571
Revolving Facility, due 2021, interest rate of 1.86% at December 31, 2016		—			160,000			—
Trade Receivable Facility, interest rate of 1.78%, 1.34% and 1.16% at June 30, 2017, December 31, 2016 and June 30, 2016, respectively		140,000			180,000			220,000
Other notes		333			356			589
Total debt		1,781,981			1,686,189			1,779,217
Less: Current maturities of long-term debt and short-term facilities		(140,037	)		(180,036	)		(238,155	)
Long-term debt	$	1,641,944		$	1,506,153		$	1,541,062

On May 22, 2017, the Company issued $300,000,000 aggregate principal amount of Floating Rate Senior Notes due in 2020 (the Floating Rate Notes) and $300,000,000 principal amount of 3.450% Senior Notes due in 2027 (the 3.450% Senior Notes, and together with the Floating Rate Notes, the Senior Notes). The Senior Notes are senior unsecured obligations of the Company. The 3.450% Senior Notes may be redeemed in whole or in part prior to March 1, 2027 at a make-whole redemption price, or on or after March 1, 2027 at a redemption price equal to 100% of the principal amount of the notes to be redeemed, in either case plus unpaid interest, if any, accrued thereon to, but excluding, the date of redemption. The Floating Rate Notes may not be redeemed prior to their stated maturity date of May 22, 2020. The Floating Rate Notes bear interest at a rate, reset quarterly, equal to the three-month LIBOR for U.S. dollars plus 0.65% (or 65 basis points). If a change of control repurchase event, as defined, occurs, the Company will be required to make an irrevocable offer to repurchase all or, at the election of each holder, any part of the Senior Notes at a repurchase price equal to 101% of their principal amount, plus unpaid interest, if any, accrued thereon to, but excluding, the date of repurchase, unless, in the case of the 3.450% Senior Notes, the Company has exercised its right to redeem such notes in full.

4.	Long-Term Debt (continued)

The Company, through a wholly-owned special-purpose subsidiary, has a $300,000,000 trade receivable securitization facility (the Trade Receivable Facility), which matures on September 27, 2017. Management intends to renew the Trade Receivable Facility beyond September 27, 2017. The Trade Receivable Facility, with SunTrust Bank, Regions Bank, PNC Bank, N.A., The Bank of Tokyo-Mitsubishi UFJ, LTD., New York Branch, 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 $422,624,000, $333,302,000 and $391,600,000 at June 30, 2017, December 31, 2016 and June 30, 2016, respectively. These receivables are originated by the Company and then sold to the wholly-owned special-purpose subsidiary by the Company. The Company 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 0.725%, subject to change in the event that this rate no longer reflects the lender’s cost of lending. The Trade Receivable Facility contains a cross-default provision to the Company’s other debt agreements.

The Company has a $700,000,000 five-year senior unsecured revolving facility (the Revolving Facility) with JPMorgan Chase Bank, N.A., as Administrative Agent, Branch Banking and Trust Company (BB&T), Deutsche Bank Securities, Inc., SunTrust Bank and Wells Fargo Bank, N.A., as Co-Syndication Agents, and the lenders party thereto. The Revolving Facility requires the Company’s ratio of consolidated debt-to-consolidated earnings before interest, taxes, depreciation, depletion and amortization (EBITDA), as defined by the Revolving Facility, for the trailing-twelve months (the Ratio) to not exceed 3.50x as of the end of any fiscal quarter, provided that the Company may exclude from the Ratio debt incurred in connection with certain acquisitions during such quarter or the three preceding quarters so long as 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 Company is a co-borrower, may be reduced by the Company’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. The Company was in compliance with this Ratio at June 30, 2017.

Available borrowings under the Revolving Facility are reduced by any outstanding letters of credit issued by the Company under the Revolving Facility. At June 30, 2017, December 31, 2016 and June 30, 2016, the Company had $2,507,000 of outstanding letters of credit issued under the Revolving Facility.

Current maturities of long-term debt and short-term facilities consist of borrowings under the Trade Receivable Facility as well as the current portions of the other notes. The 6.65% Senior Notes, due 2018, have been classified as a noncurrent liability as the Company has the intent and ability to refinance on a long-term basis before or at its maturity on April 15, 2018.

Accumulated other comprehensive loss includes the unamortized value of terminated forward starting interest rate swap agreements. For the three and six months ended June 30, 2017, the Company recognized $364,000 and $720,000, respectively, as additional interest expense. For the three and six months ended June 30, 2016, the Company recognized $340,000 and $672,000, 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

6 Months Ended

Jun. 30, 2017

Financial Instruments Disclosure [Abstract]

Financial Instruments

5.	Financial Instruments

The Company’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 Company’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.

The carrying values and fair values of the Company’s long-term debt were $1,781,981,000 and $1,885,231,000, respectively, at June 30, 2017; $1,686,189,000 and $1,752,338,000, respectively, at December 31, 2016; and $1,779,217,000 and $1,890,319,000, respectively, at June 30, 2016. 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

6 Months Ended

Jun. 30, 2017

Income Tax Disclosure [Abstract]

Income Taxes

6.	Income Taxes

The Company’s effective income tax rate for the six months ended June 30, 2017 was 26.5%. The effective income tax rate reflects 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 six months ended June 30, 2017, as a result of the adoption of ASU 2016-09 (see Note 1), the effective income tax rate reflects the excess tax benefit related to the vesting and exercise of stock-based compensation awards, which are treated as discrete events, and had a favorable impact of 210 basis points on the tax rate. As previously stated in Note 1, this requirement of the ASU is prospective and therefore, the prior-year effective income tax rate of 30.4% is not comparable.

The Company 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

6 Months Ended

Jun. 30, 2017

Compensation And Retirement Disclosure [Abstract]

Pension and Postretirement Benefits

7.	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 June 30,
	Pension						Postretirement Benefits
	2017			2016			2017			2016
	(Dollars in Thousands)
Service cost	$	6,548		$	5,776		$	22		$	24
Interest cost		8,673			9,331			198			259
Expected return on assets		(10,071	)		(9,822	)		—			—
Amortization of:
Prior service cost (credit)		113			91			(471	)		(609	)
Actuarial loss (gain)		3,551			3,146			(99	)		(139	)
Special termination benefit		—			638			—			(8	)
Net periodic benefit cost (credit)	$	8,814		$	9,160		$	(350	)	$	(473	)

	Six Months Ended June 30,
	Pension						Postretirement Benefits
	2017			2016			2017			2016
	(Dollars in Thousands)
Service cost	$	13,402		$	11,082		$	40		$	43
Interest cost		18,030			17,938			365			432
Expected return on assets		(20,613	)		(18,848	)		—			—
Amortization of:
Prior service cost (credit)		155			175			(871	)		(981	)
Actuarial loss (gain)		7,087			6,036			(182	)		(249	)
Settlement charge		—			59			—			—
Special termination benefit		—			764			—			(8	)
Net periodic benefit cost (credit)	$	18,061		$	17,206		$	(648	)	$	(763	)

The components of net periodic benefit cost (credit), other than the service cost component, are included in other nonoperating income, net, in the consolidated statements of earnings and comprehensive earnings.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

8.	Commitments and Contingencies

Legal and Administrative Proceedings

The Company 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 Company and its subsidiaries, will have a material adverse effect on the overall results of the Company’s operations, its cash flows or its financial position.

Borrowing Arrangements with Affiliate

The Company 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 Company for any payments and expenses the Company may incur from this agreement. The Company 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 Company has a $6,000,000 interest-only loan, due December 31, 2019, outstanding from this unconsolidated affiliate as of June 30, 2017, December 31, 2016 and June 30, 2016. The interest rate is one-month LIBOR plus 1.75%.

Business Segments

6 Months Ended

Jun. 30, 2017

Segment Reporting [Abstract]

Business Segments

9.	Business Segments

The Building Materials business contains three reportable business segments: Mid-America Group, Southeast Group and West Group. The Company also has a Magnesia Specialties segment. The Company’s evaluation of performance and allocation of resources are based primarily on earnings from operations. Consolidated earnings from operations include net sales less cost of sales, selling, general and administrative expenses, acquisition-related expenses, net, other operating income and expenses, net, and exclude interest expense, other nonoperating income and expenses, net, and taxes on income. Corporate consolidated loss from operations primarily includes depreciation on capitalized interest, expenses for corporate administrative functions, acquisition-related expenses, net, and other nonrecurring and/or non-operational income and expenses excluded from the Company’s evaluation of business segment performance and resource allocation. All debt and related interest expense is held at Corporate.

The following table displays selected financial data for continuing operations for the Company’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 represent net sales from one segment to another segment which are eliminated.

9.	Business Segments (continued)

Effective with a management change previously discussed in Note 1, the cement product line is reported in the West Group. Prior-year segment information has been reclassified to conform to the presentation of the Company’s current reportable segments and for the adoption of ASU 2017-07.

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2017			2016			2017			2016
	(Dollars in Thousands)
Total revenues:
Mid-America Group	$	290,899		$	278,676		$	479,918		$	465,023
Southeast Group		92,348			87,600			182,630			159,271
West Group		610,248			547,386			1,106,230			1,013,932
Total Building Materials Business		993,495			913,662			1,768,778			1,638,226
Magnesia Specialties		70,029			63,636			138,605			127,806
Total	$	1,063,524		$	977,298		$	1,907,383		$	1,766,032

Net sales:
Mid-America Group	$	269,844		$	258,988		$	447,181		$	432,360
Southeast Group		88,489			82,676			175,148			149,961
West Group		573,402			514,906			1,037,828			948,704
Total Building Materials Business		931,735			856,570			1,660,157			1,531,025
Magnesia Specialties		64,554			58,866			127,816			118,371
Total	$	996,289		$	915,436		$	1,787,973		$	1,649,396

Earnings (Loss) from operations:
Mid-America Group	$	85,363		$	80,792		$	98,705		$	95,486
Southeast Group		14,334			11,614			24,449			18,642
West Group		112,491			99,357			173,724			165,163
Total Building Materials Business		212,188			191,763			296,878			279,291
Magnesia Specialties		21,118			19,277			40,999			39,887
Corporate		(20,454	)		(20,192	)		(47,875	)		(42,306	)
Total	$	212,852		$	190,848		$	290,002		$	276,872

9.	Business Segments (continued)

The Building Materials business includes the aggregates, cement, ready mixed concrete and asphalt and paving product lines. All cement, ready mixed concrete and asphalt and paving product lines reside in the West Group. The following table, which is reconciled to consolidated amounts, provides net sales and gross profit by business: Building Materials (further divided by product line) and Magnesia Specialties.

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2017			2016			2017			2016
	(Dollars in Thousands)
Net sales:
Aggregates	$	578,388		$	547,293		$	1,029,767		$	978,153
Cement		99,016			87,440			192,700			184,300
Ready Mixed Concrete		241,894			214,947			464,275			401,799
Asphalt and Paving		111,975			88,081			138,577			101,918
Less: Interproduct Sales		(99,538	)		(81,191	)		(165,162	)		(135,145	)
Total Building Materials Business		931,735			856,570			1,660,157			1,531,025
Magnesia Specialties		64,554			58,866			127,816			118,371
Total	$	996,289		$	915,436		$	1,787,973		$	1,649,396

Gross profit (loss):
Aggregates	$	173,487		$	165,044		$	252,765		$	247,080
Cement		29,448			24,048			60,358			56,663
Ready Mixed Concrete		26,863			25,301			46,655			43,200
Asphalt and Paving		20,358			12,867			15,568			6,591
Total Building Materials Business		250,156			227,260			375,346			353,534
Magnesia Specialties		23,624			21,720			45,939			44,718
Corporate		314			(1,549	)		(125	)		(5,571	)
Total	$	274,094		$	247,431		$	421,160		$	392,681

Other Operating Income, Net

6 Months Ended

Jun. 30, 2017

Other Income And Expenses [Abstract]

Other Operating Income, Net

10.	Other Operating Income, Net

Other operating income, net, for the quarter ended June 30, 2017, reflects a $13,500,000 gain on the sale of real estate and $6,100,000 of expense, including both cash and stock-based compensation components, related to the pending retirement of Anne Lloyd, Chief Financial Officer. The vesting of Ms. Lloyd’s shares of restricted stock awards, performance stock awards and stock options will continue on their original vesting schedules, which extend beyond Ms. Lloyd's retirement date. Accordingly, the Company recognized all remaining expense related to the stock-based awards.

Supplemental Cash Flow Information

6 Months Ended

Jun. 30, 2017

Supplemental Cash Flow Elements [Abstract]

Supplemental Cash Flow Information

11.	Supplemental Cash Flow Information

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

	Six Months Ended
	June 30,
	2017			2016
	(Dollars in Thousands)
Other current and noncurrent assets	$	(32,332	)	$	(9,691	)
Accrued salaries, benefits and payroll taxes		(7,892	)		(7,808	)
Accrued insurance and other taxes		(134	)		(256	)
Accrued income taxes		28,047			(8,495	)
Accrued pension, postretirement and postemployment benefits		11,521			11,757
Other current and noncurrent liabilities		30,740			(5,477	)
	$	29,950		$	(19,970	)

The change in other current and noncurrent assets and other current and noncurrent liabilities is primarily attributable to an accrual of insurance claims over the deductible limits. Additionally, the change in other current and noncurrent liabilities is due to retirement expense in the current year and the write-off of coal contracts in the prior year. The change in accrued income taxes is attributable to net operating loss carryforwards utilized in the prior year.

Noncash investing and financing activities are as follows:

	Six Months Ended
	June 30,
	2017		2016
	(Dollars in Thousands)
Noncash investing and financing activities:
Accrued liabilities for purchases of property, plant and equipment	$	34,714	$	33,959
Acquisition of assets through capital lease	$	149	$	—
Settlement of royalty obligation via asset sale	$	900	$	—

Supplemental disclosures of cash flow information are as follows:

	Six Months Ended
	June 30,
	2017		2016
	(Dollars in Thousands)
Cash paid for interest	$	38,111	$	36,630
Cash paid for income taxes	$	33,264	$	47,159

Business Combinations

6 Months Ended

Jun. 30, 2017

Business Combinations [Abstract]

Business Combinations

12.	Business Combinations

In the first quarter 2016, the Company 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 Company’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.

In July 2016, the Company acquired the remaining interest in Ratliff Ready-Mix, L.P. (Ratliff), which operates ready mixed concrete plants in central Texas. Prior to the acquisition, the Company owned a 40% interest in Ratliff which was accounted for under the equity method. The Company was required to re-measure the existing 40% interest to fair value upon closing of the transaction, resulting in a gain of $5,863,000, which was recorded in other nonoperating income in third quarter 2016. These operations are reported in the West Group. The Company recorded fair values of the assets acquired and liabilities assumed; however, deferred income taxes and goodwill are subject to change upon review of the seller’s final tax return.

The impact of these acquisitions on the operating results was not considered material; therefore, pro forma financial information is not included.

Pending Acquisition of Bluegrass Materials

6 Months Ended

Jun. 30, 2017

Business Combinations [Abstract]

Pending Acquisition of Bluegrass Materials

13.	Pending Acquisition of Bluegrass Materials

On June 26, 2017, the Company announced a definitive agreement to acquire Bluegrass Materials Company (Bluegrass) for $1,625,000,000 in cash. The purchase price will be increased dollar-for-dollar by any cash on hand held by Bluegrass and decreased by the amount of any outstanding debt of Bluegrass, each as of the closing of the transaction. Bluegrass is the largest privately held, pure-play aggregates business in the United States and has a portfolio of 23 active sites with more than 125 years of strategically-located, high-quality reserves, in Georgia, South Carolina, Tennessee, Maryland and Kentucky. These operations complement the Company’s existing southeastern footprint and provides a new growth platform within the southern portion of the Northeast Megaregion. The transaction is expected to close in the fourth quarter of 2017, subject to regulatory approvals and other customary closing conditions.

Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2017

Accounting Policies [Abstract]

Organization

BUILDING MATERIALS 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

Product Lines	Aggregates	Aggregates	Aggregates, cement, ready mixed concrete and asphalt and paving

Products and Services	Crushed stone, sand and gravel	Crushed stone, sand and gravel	Crushed stone, sand and gravel; Portland and specialty cements; ready mixed concrete and asphalt and paving

Basis of Presentation

New Accounting Pronouncements

Share-Based Payment Accounting

1.	Significant Accounting Policies (continued)

New Accounting Pronouncements

Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

Pending Accounting Pronouncements

Revenue Recognition Standard

Lease Standard

Reclassifications

Prior-year information has been reclassified to conform to the presentation of the Company’s current reportable segments and for the adoption of the two accounting pronouncements aforementioned.

Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss

Comprehensive earnings attributable to Martin Marietta is as follows:

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2017		2016			2017		2016
	(Dollars in Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	142,279	$	122,052		$	184,613	$	167,047
Other comprehensive earnings (loss), net of tax		2,519		(2,235	)		4,781		(446	)
Comprehensive earnings attributable to Martin Marietta Materials, Inc.	$	144,798	$	119,817		$	189,394	$	166,601

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					Six Months Ended
	June 30,					June 30,
	2017			2016		2017			2016
	(Dollars in Thousands)
Net (loss) earnings attributable to noncontrolling interests	$	(38	)	$	61	$	(65	)	$	122
Other comprehensive earnings, net of tax		1			2		2			33
Comprehensive (loss) earnings attributable to noncontrolling interests	$	(37	)	$	63	$	(63	)	$	155

1.	Significant Accounting Policies (continued)

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

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 June 30, 2017
Balance at beginning of period	$	(126,463	)	$	(1,025	)	$	(937	)	$	(128,425	)
Other comprehensive earnings before reclassifications, net of tax		—			389			—			389
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,910			—			220			2,130
Other comprehensive earnings, net of tax		1,910			389			220			2,519
Balance at end of period	$	(124,553	)	$	(636	)	$	(717	)	$	(125,906	)

	Three Months Ended June 30, 2016
Balance at beginning of period	$	(101,907	)	$	(149	)	$	(1,777	)	$	(103,833	)
Other comprehensive loss before reclassifications, net of tax		(3,736	)		(232	)		—			(3,968	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,529			—			204			1,733
Other comprehensive (loss) earnings, net of tax		(2,207	)		(232	)		204			(2,235	)
Balance at end of period	$	(104,114	)	$	(381	)	$	(1,573	)	$	(106,068	)

1.	Significant Accounting Policies (continued)

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

	(Dollars in Thousands)
							Unamortized
							Value of
							Terminated			Accumulated
	Pension and						Forward Starting			Other
	Postretirement			Foreign			Interest Rate			Comprehensive
	Benefit Plans			Currency			Swap			Loss
	Six Months Ended June 30, 2017
Balance at beginning of period	$	(128,373	)	$	(1,162	)	$	(1,152	)	$	(130,687	)
Other comprehensive earnings before reclassifications, net of tax		—			526			—			526
Amounts reclassified from accumulated other comprehensive earnings, net of tax		3,820			—			435			4,255
Other comprehensive earnings, net of tax		3,820			526			435			4,781
Balance at end of period	$	(124,553	)	$	(636	)	$	(717	)	$	(125,906	)

	Six Months Ended June 30, 2016
Balance at beginning of period	$	(103,380	)	$	(264	)	$	(1,978	)	$	(105,622	)
Other comprehensive loss before reclassifications, net of tax		(3,830	)		(117	)		—			(3,947	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		3,096			—			405			3,501
Other comprehensive (loss) earnings, net of tax		(734	)		(117	)		405			(446	)
Balance at end of period	$	(104,114	)	$	(381	)	$	(1,573	)	$	(106,068	)

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 June 30, 2017
Balance at beginning of period	$	80,859		$	608		$	81,467
Tax effect of other comprehensive earnings		(1,184	)		(144	)		(1,328	)
Balance at end of period	$	79,675		$	464		$	80,139

	Three Months Ended June 30, 2016
Balance at beginning of period	$	65,523		$	1,159		$	66,682
Tax effect of other comprehensive earnings		1,408			(136	)		1,272
Balance at end of period	$	66,931		$	1,023		$	67,954

	Six Months Ended June 30, 2017
Balance at beginning of period	$	82,044		$	749		$	82,793
Tax effect of other comprehensive earnings		(2,369	)		(285	)		(2,654	)
Balance at end of period	$	79,675		$	464		$	80,139

	Six Months Ended June 30, 2016
Balance at beginning of period	$	66,467		$	1,290		$	67,757
Tax effect of other comprehensive earnings		464			(267	)		197
Balance at end of period	$	66,931		$	1,023		$	67,954

1.	Significant Accounting Policies (continued)

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

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Six Months Ended						Affected line items in the consolidated
	June 30,						June 30,						statements of earnings and
	2017			2016			2017			2016			comprehensive earnings
	(Dollars in Thousands)
Pension and postretirement benefit plans
Settlement charge	$	—		$	—		$	—		$	59
Amortization of:
Prior service credit		(358	)		(518	)		(716	)		(806	)
Actuarial loss		3,452			3,007			6,905			5,787
		3,094			2,489			6,189			5,040		Nonoperating expenses
Tax benefit		(1,184	)		(960	)		(2,369	)		(1,944	)	Taxes on income
	$	1,910		$	1,529		$	3,820		$	3,096

Unamortized value of terminated forward starting interest rate swap
Additional interest expense	$	364		$	340		$	720		$	672		Interest expense
Tax benefit		(144	)		(136	)		(285	)		(267	)	Taxes on income
	$	220		$	204		$	435		$	405

Earnings 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				Six Months Ended
	June 30,				June 30,
	2017		2016		2017		2016
	(In Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	142,279	$	122,052	$	184,613	$	167,047
Less: Distributed and undistributed earnings attributable to unvested awards		413		519		553		730
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$	141,866	$	121,533	$	184,060	$	166,317

Basic weighted-average common shares outstanding		62,858		63,532		62,961		63,845
Effect of dilutive employee and director awards		283		270		285		246
Diluted weighted-average common shares outstanding		63,141		63,802		63,246		64,091

Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2017

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 June 30, 2017
Balance at beginning of period	$	(126,463	)	$	(1,025	)	$	(937	)	$	(128,425	)
Other comprehensive earnings before reclassifications, net of tax		—			389			—			389
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,910			—			220			2,130
Other comprehensive earnings, net of tax		1,910			389			220			2,519
Balance at end of period	$	(124,553	)	$	(636	)	$	(717	)	$	(125,906	)

	Three Months Ended June 30, 2016
Balance at beginning of period	$	(101,907	)	$	(149	)	$	(1,777	)	$	(103,833	)
Other comprehensive loss before reclassifications, net of tax		(3,736	)		(232	)		—			(3,968	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		1,529			—			204			1,733
Other comprehensive (loss) earnings, net of tax		(2,207	)		(232	)		204			(2,235	)
Balance at end of period	$	(104,114	)	$	(381	)	$	(1,573	)	$	(106,068	)

1.	Significant Accounting Policies (continued)

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

	(Dollars in Thousands)
							Unamortized
							Value of
							Terminated			Accumulated
	Pension and						Forward Starting			Other
	Postretirement			Foreign			Interest Rate			Comprehensive
	Benefit Plans			Currency			Swap			Loss
	Six Months Ended June 30, 2017
Balance at beginning of period	$	(128,373	)	$	(1,162	)	$	(1,152	)	$	(130,687	)
Other comprehensive earnings before reclassifications, net of tax		—			526			—			526
Amounts reclassified from accumulated other comprehensive earnings, net of tax		3,820			—			435			4,255
Other comprehensive earnings, net of tax		3,820			526			435			4,781
Balance at end of period	$	(124,553	)	$	(636	)	$	(717	)	$	(125,906	)

	Six Months Ended June 30, 2016
Balance at beginning of period	$	(103,380	)	$	(264	)	$	(1,978	)	$	(105,622	)
Other comprehensive loss before reclassifications, net of tax		(3,830	)		(117	)		—			(3,947	)
Amounts reclassified from accumulated other comprehensive earnings, net of tax		3,096			—			405			3,501
Other comprehensive (loss) earnings, net of tax		(734	)		(117	)		405			(446	)
Balance at end of period	$	(104,114	)	$	(381	)	$	(1,573	)	$	(106,068	)

Noncurrent Deferred Tax Assets Recorded In Accumulated Other Comprehensive Loss

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 June 30, 2017
Balance at beginning of period	$	80,859		$	608		$	81,467
Tax effect of other comprehensive earnings		(1,184	)		(144	)		(1,328	)
Balance at end of period	$	79,675		$	464		$	80,139

	Three Months Ended June 30, 2016
Balance at beginning of period	$	65,523		$	1,159		$	66,682
Tax effect of other comprehensive earnings		1,408			(136	)		1,272
Balance at end of period	$	66,931		$	1,023		$	67,954

	Six Months Ended June 30, 2017
Balance at beginning of period	$	82,044		$	749		$	82,793
Tax effect of other comprehensive earnings		(2,369	)		(285	)		(2,654	)
Balance at end of period	$	79,675		$	464		$	80,139

	Six Months Ended June 30, 2016
Balance at beginning of period	$	66,467		$	1,290		$	67,757
Tax effect of other comprehensive earnings		464			(267	)		197
Balance at end of period	$	66,931		$	1,023		$	67,954

Reclassification Out of Accumulated Other Comprehensive Loss

1.	Significant Accounting Policies (continued)

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

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Six Months Ended						Affected line items in the consolidated
	June 30,						June 30,						statements of earnings and
	2017			2016			2017			2016			comprehensive earnings
	(Dollars in Thousands)
Pension and postretirement benefit plans
Settlement charge	$	—		$	—		$	—		$	59
Amortization of:
Prior service credit		(358	)		(518	)		(716	)		(806	)
Actuarial loss		3,452			3,007			6,905			5,787
		3,094			2,489			6,189			5,040		Nonoperating expenses
Tax benefit		(1,184	)		(960	)		(2,369	)		(1,944	)	Taxes on income
	$	1,910		$	1,529		$	3,820		$	3,096

Unamortized value of terminated forward starting interest rate swap
Additional interest expense	$	364		$	340		$	720		$	672		Interest expense
Tax benefit		(144	)		(136	)		(285	)		(267	)	Taxes on income
	$	220		$	204		$	435		$	405

Basic and Diluted Earnings 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				Six Months Ended
	June 30,				June 30,
	2017		2016		2017		2016
	(In Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	142,279	$	122,052	$	184,613	$	167,047
Less: Distributed and undistributed earnings attributable to unvested awards		413		519		553		730
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$	141,866	$	121,533	$	184,060	$	166,317

Basic weighted-average common shares outstanding		62,858		63,532		62,961		63,845
Effect of dilutive employee and director awards		283		270		285		246
Diluted weighted-average common shares outstanding		63,141		63,802		63,246		64,091

Parent

Significant Accounting Policies [Line Items]

Comprehensive Earnings

Comprehensive earnings attributable to Martin Marietta is as follows:

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2017		2016			2017		2016
	(Dollars in Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	142,279	$	122,052		$	184,613	$	167,047
Other comprehensive earnings (loss), net of tax		2,519		(2,235	)		4,781		(446	)
Comprehensive earnings attributable to Martin Marietta Materials, Inc.	$	144,798	$	119,817		$	189,394	$	166,601

Noncontrolling Interests

Significant Accounting Policies [Line Items]

Comprehensive Earnings

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					Six Months Ended
	June 30,					June 30,
	2017			2016		2017			2016
	(Dollars in Thousands)
Net (loss) earnings attributable to noncontrolling interests	$	(38	)	$	61	$	(65	)	$	122
Other comprehensive earnings, net of tax		1			2		2			33
Comprehensive (loss) earnings attributable to noncontrolling interests	$	(37	)	$	63	$	(63	)	$	155

Goodwill (Tables)

6 Months Ended

Jun. 30, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Changes in Goodwill

	(In Thousands)
	Mid-America		Southeast		West
	Group		Group		Group		Total
Balance at January 1, 2017	$	281,403	$	50,346	$	1,827,588	$	2,159,337
Adjustments to purchase price allocations		—		—		723		723
Balance at June 30, 2017	$	281,403	$	50,346	$	1,828,311	$	2,160,060

Inventories, Net (Tables)

6 Months Ended

Jun. 30, 2017

Inventory Disclosure [Abstract]

Schedule of Inventories Net

	June 30,			December 31,			June 30,
	2017			2016			2016
	(Dollars in Thousands)
Finished products	$	508,144		$	479,291		$	463,807
Products in process and raw materials		59,410			61,171			60,324
Supplies and expendable parts		120,594			116,024			113,110
		688,148			656,486			637,241
Less: Allowances		(138,283	)		(134,862	)		(132,364	)
Total	$	549,865		$	521,624		$	504,877

Long-Term Debt (Tables)

6 Months Ended

Jun. 30, 2017

Debt Disclosure [Abstract]

Long-Term Debt

	June 30,			December 31,			June 30,
	2017			2016			2016
	(Dollars in Thousands)
6.6% Senior Notes, due 2018	$	299,676		$	299,483		$	299,294
7% Debentures, due 2025		124,134			124,090			124,046
6.25% Senior Notes, due 2037		228,003			227,975			227,947
4.25% Senior Notes, due 2024		395,532			395,252			394,977
3.45% Senior Notes, due 2027		296,456			—			—
Floating Rate Notes, due 2020, interest rate of 1.82% at June 30, 2017		297,847			—			—
Floating Rate Notes, due 2017, interest rate of 2.10% and 1.73% at December 31, 2016 and June 30, 2016, respectively		—			299,033			298,793
Term Loan Facility, due 2018, interest rate of 1.96% at June 30, 2016		—			—			213,571
Revolving Facility, due 2021, interest rate of 1.86% at December 31, 2016		—			160,000			—
Trade Receivable Facility, interest rate of 1.78%, 1.34% and 1.16% at June 30, 2017, December 31, 2016 and June 30, 2016, respectively		140,000			180,000			220,000
Other notes		333			356			589
Total debt		1,781,981			1,686,189			1,779,217
Less: Current maturities of long-term debt and short-term facilities		(140,037	)		(180,036	)		(238,155	)
Long-term debt	$	1,641,944		$	1,506,153		$	1,541,062

- 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=84159872&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=75038535&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=64930739&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=84159872&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=84159872&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=64930785&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=64930785&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=84159872&loc=d3e21521-112644

+ Details

Pension and Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2017

Compensation And Retirement Disclosure [Abstract]

Schedule of Components of Net Periodic Benefit Cost (Credit)

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

	Three Months Ended June 30,
	Pension						Postretirement Benefits
	2017			2016			2017			2016
	(Dollars in Thousands)
Service cost	$	6,548		$	5,776		$	22		$	24
Interest cost		8,673			9,331			198			259
Expected return on assets		(10,071	)		(9,822	)		—			—
Amortization of:
Prior service cost (credit)		113			91			(471	)		(609	)
Actuarial loss (gain)		3,551			3,146			(99	)		(139	)
Special termination benefit		—			638			—			(8	)
Net periodic benefit cost (credit)	$	8,814		$	9,160		$	(350	)	$	(473	)

	Six Months Ended June 30,
	Pension						Postretirement Benefits
	2017			2016			2017			2016
	(Dollars in Thousands)
Service cost	$	13,402		$	11,082		$	40		$	43
Interest cost		18,030			17,938			365			432
Expected return on assets		(20,613	)		(18,848	)		—			—
Amortization of:
Prior service cost (credit)		155			175			(871	)		(981	)
Actuarial loss (gain)		7,087			6,036			(182	)		(249	)
Settlement charge		—			59			—			—
Special termination benefit		—			764			—			(8	)
Net periodic benefit cost (credit)	$	18,061		$	17,206		$	(648	)	$	(763	)

Business Segments (Tables)

6 Months Ended

Jun. 30, 2017

Segment Reporting [Abstract]

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

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2017			2016			2017			2016
	(Dollars in Thousands)
Total revenues:
Mid-America Group	$	290,899		$	278,676		$	479,918		$	465,023
Southeast Group		92,348			87,600			182,630			159,271
West Group		610,248			547,386			1,106,230			1,013,932
Total Building Materials Business		993,495			913,662			1,768,778			1,638,226
Magnesia Specialties		70,029			63,636			138,605			127,806
Total	$	1,063,524		$	977,298		$	1,907,383		$	1,766,032

Net sales:
Mid-America Group	$	269,844		$	258,988		$	447,181		$	432,360
Southeast Group		88,489			82,676			175,148			149,961
West Group		573,402			514,906			1,037,828			948,704
Total Building Materials Business		931,735			856,570			1,660,157			1,531,025
Magnesia Specialties		64,554			58,866			127,816			118,371
Total	$	996,289		$	915,436		$	1,787,973		$	1,649,396

Earnings (Loss) from operations:
Mid-America Group	$	85,363		$	80,792		$	98,705		$	95,486
Southeast Group		14,334			11,614			24,449			18,642
West Group		112,491			99,357			173,724			165,163
Total Building Materials Business		212,188			191,763			296,878			279,291
Magnesia Specialties		21,118			19,277			40,999			39,887
Corporate		(20,454	)		(20,192	)		(47,875	)		(42,306	)
Total	$	212,852		$	190,848		$	290,002		$	276,872

Net Sales and Gross Profit by Line of Business

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2017			2016			2017			2016
	(Dollars in Thousands)
Net sales:
Aggregates	$	578,388		$	547,293		$	1,029,767		$	978,153
Cement		99,016			87,440			192,700			184,300
Ready Mixed Concrete		241,894			214,947			464,275			401,799
Asphalt and Paving		111,975			88,081			138,577			101,918
Less: Interproduct Sales		(99,538	)		(81,191	)		(165,162	)		(135,145	)
Total Building Materials Business		931,735			856,570			1,660,157			1,531,025
Magnesia Specialties		64,554			58,866			127,816			118,371
Total	$	996,289		$	915,436		$	1,787,973		$	1,649,396

Gross profit (loss):
Aggregates	$	173,487		$	165,044		$	252,765		$	247,080
Cement		29,448			24,048			60,358			56,663
Ready Mixed Concrete		26,863			25,301			46,655			43,200
Asphalt and Paving		20,358			12,867			15,568			6,591
Total Building Materials Business		250,156			227,260			375,346			353,534
Magnesia Specialties		23,624			21,720			45,939			44,718
Corporate		314			(1,549	)		(125	)		(5,571	)
Total	$	274,094		$	247,431		$	421,160		$	392,681

Supplemental Cash Flow Information (Tables)

6 Months Ended

Jun. 30, 2017

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:

	Six Months Ended
	June 30,
	2017			2016
	(Dollars in Thousands)
Other current and noncurrent assets	$	(32,332	)	$	(9,691	)
Accrued salaries, benefits and payroll taxes		(7,892	)		(7,808	)
Accrued insurance and other taxes		(134	)		(256	)
Accrued income taxes		28,047			(8,495	)
Accrued pension, postretirement and postemployment benefits		11,521			11,757
Other current and noncurrent liabilities		30,740			(5,477	)
	$	29,950		$	(19,970	)

Schedule Of Noncash Investing and Financing Activities

Noncash investing and financing activities are as follows:

	Six Months Ended
	June 30,
	2017		2016
	(Dollars in Thousands)
Noncash investing and financing activities:
Accrued liabilities for purchases of property, plant and equipment	$	34,714	$	33,959
Acquisition of assets through capital lease	$	149	$	—
Settlement of royalty obligation via asset sale	$	900	$	—

Supplemental Disclosures of Cash Flow Information

Supplemental disclosures of cash flow information are as follows:

	Six Months Ended
	June 30,
	2017		2016
	(Dollars in Thousands)
Cash paid for interest	$	38,111	$	36,630
Cash paid for income taxes	$	33,264	$	47,159

Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) State	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Facility State Segment	Jun. 30, 2016 USD ($)
Significant Accounting Policies [Line Items]
Number of states with aggregates business sales by destination \| State	26		26
Number of reportable segments \| Segment			3
Shares withheld for income tax obligations reclassified from operating activity to financing activity			$ 8,938,000	$ 5,546,000
ASU 2016-09
Significant Accounting Policies [Line Items]
Shares withheld for income tax obligations reclassified from operating activity to financing activity				2,525,000
Excess tax benefits from stock-based compensation recognized as operating activities	$ 2,989,000		$ 5,259,000	3,948,000
ASU 2017-07 \| Cost of Sales
Significant Accounting Policies [Line Items]
Reclassification of costs to nonoperating expense		$ 730,000		1,346,000
ASU 2017-07 \| Selling, General and Administrative Expenses
Significant Accounting Policies [Line Items]
Reclassification of costs to nonoperating expense		1,728,000		3,240,000
ASU 2017-07 \| Other Operating Income and Expenses
Significant Accounting Policies [Line Items]
Reclassification of costs to nonoperating expense		$ 648,000		$ 774,000
Minimum
Significant Accounting Policies [Line Items]
Number of quarries distribution facilities and plants \| Facility			270

Comprehensive Earnings Attributable to Martin Marietta Materials Incorporated (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net earnings attributable to Martin Marietta Materials, Inc.	$ 142,279	$ 122,052	$ 184,613	$ 167,047
Other comprehensive earnings (loss), net of tax	2,519	(2,235)	4,781	(446)
Earnings attributable to Martin Marietta Materials, Inc.	$ 144,798	$ 119,817	$ 189,394	$ 166,601

Comprehensive Earnings Attributable to Noncontrolling Interests (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) earnings attributable to noncontrolling interests	$ (38)	$ 61	$ (65)	$ 122
Other comprehensive earnings, net of tax	1	2	2	33
Comprehensive (loss) earnings attributable to noncontrolling interests	$ (37)	$ 63	$ (63)	$ 155

Changes in Accumulated Other Comprehensive Earnings (Loss), Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 4,142,590
Other comprehensive earnings (loss) before reclassifications, net of tax	$ 389	$ (3,968)	526	$ (3,947)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	2,130	1,733	4,255	3,501
Other comprehensive (loss) earnings, net of tax	2,519	(2,235)	4,781	(446)
Ending Balance	4,200,531	4,016,500	4,200,531	4,016,500
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(126,463)	(101,907)	(128,373)	(103,380)
Other comprehensive earnings (loss) before reclassifications, net of tax		(3,736)		(3,830)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	1,910	1,529	3,820	3,096
Other comprehensive (loss) earnings, net of tax	1,910	(2,207)	3,820	(734)
Ending Balance	(124,553)	(104,114)	(124,553)	(104,114)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(1,025)	(149)	(1,162)	(264)
Other comprehensive earnings (loss) before reclassifications, net of tax	389	(232)	526	(117)
Other comprehensive (loss) earnings, net of tax	389	(232)	526	(117)
Ending Balance	(636)	(381)	(636)	(381)
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(937)	(1,777)	(1,152)	(1,978)
Amounts reclassified from accumulated other comprehensive earnings, net of tax	220	204	435	405
Other comprehensive (loss) earnings, net of tax	220	204	435	405
Ending Balance	(717)	(1,573)	(717)	(1,573)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(128,425)	(103,833)	(130,687)	(105,622)
Ending Balance	$ (125,906)	$ (106,068)	$ (125,906)	$ (106,068)

Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
Balance at beginning of period, Pension and Postretirement Benefit Plans	$ 80,859	$ 65,523	$ 82,044	$ 66,467
Tax effect of other comprehensive earnings, Pension and Postretirement Benefit Plans	(1,184)	1,408	(2,369)	464
Balance at end of period, Pension and Postretirement Benefit Plans	79,675	66,931	79,675	66,931
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	608	1,159	749	1,290
Tax effect of other comprehensive earnings, Unamortized Value of Terminated Forward Starting Interest Rate Swap	(144)	(136)	(285)	(267)
Balance at end of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap	464	1,023	464	1,023
Balance at beginning of period, Net Noncurrent Deferred Tax Assets	81,467	66,682	82,793	67,757
Tax effect of other comprehensive earnings, Net Noncurrent Deferred Tax Assets	(1,328)	1,272	(2,654)	197
Balance at end of period, Net Noncurrent Deferred Tax Assets	$ 80,139	$ 67,954	$ 80,139	$ 67,954

Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Additional interest expense	$ 24,045	$ 20,294	$ 44,896	$ 40,328
Tax benefit	51,986	53,435	66,514	73,145
Earnings from Continuing Operations	2,130	1,733	4,255	3,501
Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	1,910	1,529	3,820	3,096
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	220	204	435	405
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	(358)	(518)	(716)	(806)
Actuarial loss	3,452	3,007	6,905	5,787
Tax benefit	(1,184)	(960)	(2,369)	(1,944)
Earnings from Continuing Operations	1,910	1,529	3,820	3,096
Reclassification out of Accumulated Other Comprehensive Income \| Pension and Postretirement Benefit Plans \| Nonoperating Expenses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications out of accumulated other comprehensive loss before taxes	3,094	2,489	6,189	5,040
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]
Additional interest expense	364	340	720	672
Tax benefit	(144)	(136)	(285)	(267)
Earnings from Continuing Operations	$ 220	$ 204	$ 435	$ 405

Basic and Diluted Earnings Per Common Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net earnings attributable to Martin Marietta Materials, Inc.	$ 142,279	$ 122,052	$ 184,613	$ 167,047
Less: Distributed and undistributed earnings attributable to unvested awards	413	519	553	730
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$ 141,866	$ 121,533	$ 184,060	$ 166,317
Basic weighted-average common shares outstanding	62,858	63,532	62,961	63,845
Effect of dilutive employee and director awards	283	270	285	246
Diluted weighted-average common shares outstanding	63,141	63,802	63,246	64,091

Changes in Goodwill (Detail) $ in Thousands	6 Months Ended
Changes in Goodwill (Detail) $ in Thousands	Jun. 30, 2017 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 2,159,337
Adjustments to purchase price allocations	723
Balance at end of period	2,160,060
Mid-America Group
Goodwill [Line Items]
Balance at beginning of period	281,403
Balance at end of period	281,403
Southeast Group
Goodwill [Line Items]
Balance at beginning of period	50,346
Balance at end of period	50,346
West Group
Goodwill [Line Items]
Balance at beginning of period	1,827,588
Adjustments to purchase price allocations	723
Balance at end of period	$ 1,828,311

Schedule of Inventories Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Inventory Disclosure [Abstract]
Finished products	$ 508,144	$ 479,291	$ 463,807
Products in process and raw materials	59,410	61,171	60,324
Supplies and expendable parts	120,594	116,024	113,110
Inventories, Gross	688,148	656,486	637,241
Less: Allowances	(138,283)	(134,862)	(132,364)
Total	$ 549,865	$ 521,624	$ 504,877

Long-Term Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Debt Instrument [Line Items]
Total debt	$ 1,781,981	$ 1,686,189	$ 1,779,217
Less: Current maturities of long-term debt and short-term facilities	(140,037)	(180,036)	(238,155)
Long-term debt	1,641,944	1,506,153	1,541,062
Revolving Facility, Due 2021
Debt Instrument [Line Items]
Total debt		160,000
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Total debt	299,676	299,483	299,294
7% Debentures, Due 2025
Debt Instrument [Line Items]
Total debt	124,134	124,090	124,046
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Total debt	228,003	227,975	227,947
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total debt	395,532	395,252	394,977
3.45% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total debt	296,456
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Total debt		299,033	298,793
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Total debt	297,847
Term Loan Facility, Due 2018
Debt Instrument [Line Items]
Total debt			213,571
Trade Receivable Facility
Debt Instrument [Line Items]
Total debt	140,000	180,000	220,000
Other Notes
Debt Instrument [Line Items]
Total debt	$ 333	$ 356	$ 589

Long-Term Debt (Parenthetical) (Detail)		6 Months Ended
Long-Term Debt (Parenthetical) (Detail)	May 22, 2017	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Revolving Facility, Due 2021
Debt Instrument [Line Items]
Maturity year		2021
Credit Facility interest rate			1.86%
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Maturity year		2018
Interest rate on notes		6.60%
7% Debentures, Due 2025
Debt Instrument [Line Items]
Maturity year		2025
Interest rate on notes		7.00%
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Maturity year		2037
Interest rate on notes		6.25%
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Maturity year		2024
Interest rate on notes		4.25%
3.45% Senior Notes, Due 2027
Debt Instrument [Line Items]
Maturity year	2027	2027
Interest rate on notes	3.45%	3.45%
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Maturity year	2020	2017
Interest rate			2.10%	1.73%
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Maturity year		2020
Interest rate		1.82%
Term Loan Facility, Due 2018
Debt Instrument [Line Items]
Maturity year		2018
Interest rate				1.96%
Trade Receivable Facility
Debt Instrument [Line Items]
Credit Facility interest rate		1.78%	1.34%	1.16%

Long-Term Debt - Additional information (Detail) - USD ($)		3 Months Ended		6 Months Ended
	May 22, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 27, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Redemption price percentage of principal amount of notes redeemed	100.00%
Required offer price to repurchase senior notes if change of control repurchase event				101.00%
Maximum consolidated debt reduction for unrestricted cash and cash equivalents for debt covenant calculation				$ 200,000,000
Additional interest expense		$ 364,000	$ 340,000	720,000	$ 672,000
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		3.50
Excluding Acquisition Bridge Debt \| Maximum
Debt Instrument [Line Items]
Debt covenant		3.75		3.75
Revolving Facility
Debt Instrument [Line Items]
Credit facility commitment		$ 700,000,000		$ 700,000,000
Senior unsecured revolving facility, maturity period				5 years
Outstanding letters of credit		$ 2,507,000	2,507,000	$ 2,507,000	2,507,000		$ 2,507,000
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Senior notes, principal amount	$ 300,000,000
Maturity year	2020			2017
3.45% Senior Notes, Due 2027
Debt Instrument [Line Items]
Senior notes, principal amount	$ 300,000,000
Maturity year	2027			2027
Interest rate on notes	3.45%	3.45%		3.45%
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Maturity year				2020
Debt instrument, maturity date				May 22, 2020
Trade Receivable Facility
Debt Instrument [Line Items]
Debt instrument maturity period				Sep. 27, 2017
Debt instrument maturity, description				Management intends to renew the Trade Receivable Facility beyond September 27, 2017.
Credit facility borrowing base		$ 422,624,000	$ 391,600,000	$ 422,624,000	$ 391,600,000		$ 333,302,000
Trade Receivable Facility \| Scenario Forecast
Debt Instrument [Line Items]
Credit facility commitment						$ 300,000,000
6.65% Senior Notes, Due 2018
Debt Instrument [Line Items]
Maturity year				2018
Interest rate on notes		6.65%		6.65%
Debt instrument, maturity date				Apr. 15, 2018
Debt instrument maturity, description				The 6.65% Senior Notes, due 2018, have been classified as a noncurrent liability as the Company has the intent and ability to refinance on a long-term basis before or at its maturity on April 15, 2018.
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Maturity year				2018
Interest rate on notes		6.60%		6.60%
Increase in annual interest expense due to ongoing amortization of the terminated value of the swap agreements				$ 1,400,000
Three-month LIBOR \| Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Basis spread on variable rate	0.65%
London Interbank Offered Rate(LIBOR) \| Trade Receivable Facility
Debt Instrument [Line Items]
Basis spread on variable rate				0.725%
Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Debt instrument, redemption description				The 3.450% Senior Notes may be redeemed in whole or in part prior to March 1, 2027 at a make-whole redemption price
Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Debt instrument, redemption description				or on or after March 1, 2027 at a redemption price equal to 100% of the principal amount of the notes to be redeemed, in either case plus unpaid interest, if any, accrued thereon to, but excluding, the date of redemption.

Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Long-term debt, carrying values	$ 1,781,981	$ 1,686,189	$ 1,779,217
Long-term debt, fair values	$ 1,885,231	$ 1,752,338	$ 1,890,319

Income Taxes - Additional Information (Detail)	6 Months Ended	12 Months Ended
Income Taxes - Additional Information (Detail)	Jun. 30, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Effective income tax rate	26.50%	30.40%
Adoption of ASU 2016-09
Income Taxes [Line Items]
Favorable basis points on tax rate related to vesting and exercise of stock-based compensation awards	2.10%

Schedule of Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6,548	$ 5,776	$ 13,402	$ 11,082
Interest cost	8,673	9,331	18,030	17,938
Expected return on assets	(10,071)	(9,822)	(20,613)	(18,848)
Prior service cost (credit)	113	91	155	175
Actuarial loss (gain)	3,551	3,146	7,087	6,036
Settlement charge				59
Special termination benefit		638		764
Net periodic benefit cost (credit)	8,814	9,160	18,061	17,206
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	22	24	40	43
Interest cost	198	259	365	432
Prior service cost (credit)	(471)	(609)	(871)	(981)
Actuarial loss (gain)	(99)	(139)	(182)	(249)
Special termination benefit		(8)		(8)
Net periodic benefit cost (credit)	$ (350)	$ (473)	$ (648)	$ (763)

Commitments and Contingencies - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Commitments and Contingencies [Line Items]
Guarantee of affiliate's obligations	$ 25,000,000
Interest-only loan
Commitments and Contingencies [Line Items]
Due from affiliate	$ 6,000,000	$ 6,000,000	$ 6,000,000
Due date	Dec. 31, 2019
Interest-only loan \| London Interbank Offered Rate(LIBOR)
Commitments and Contingencies [Line Items]
Basis spread on variable rate	1.75%

Business Segments - Additional Information (Detail)	6 Months Ended
Business Segments - Additional Information (Detail)	Jun. 30, 2017 Segment
Segment Reporting [Abstract]
Reportable business segments	3

Financial Data for Continuing Operations for Company's Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 1,063,524	$ 977,298	$ 1,907,383	$ 1,766,032
Net sales	996,289	915,436	1,787,973	1,649,396
Earnings (Loss) from operations	212,852	190,848	290,002	276,872
Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	993,495	913,662	1,768,778	1,638,226
Net sales	931,735	856,570	1,660,157	1,531,025
Earnings (Loss) from operations	212,188	191,763	296,878	279,291
Operating Segments \| Mid-America Group \| Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	290,899	278,676	479,918	465,023
Net sales	269,844	258,988	447,181	432,360
Earnings (Loss) from operations	85,363	80,792	98,705	95,486
Operating Segments \| Southeast Group \| Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	92,348	87,600	182,630	159,271
Net sales	88,489	82,676	175,148	149,961
Earnings (Loss) from operations	14,334	11,614	24,449	18,642
Operating Segments \| West Group \| Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	610,248	547,386	1,106,230	1,013,932
Net sales	573,402	514,906	1,037,828	948,704
Earnings (Loss) from operations	112,491	99,357	173,724	165,163
Operating Segments \| Magnesia Specialties
Segment Reporting Information [Line Items]
Total revenues	70,029	63,636	138,605	127,806
Net sales	64,554	58,866	127,816	118,371
Earnings (Loss) from operations	21,118	19,277	40,999	39,887
Corporate
Segment Reporting Information [Line Items]
Earnings (Loss) from operations	$ (20,454)	$ (20,192)	$ (47,875)	$ (42,306)

Net Sales and Gross Profit by Line of Business (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Product Information [Line Items]
Net sales	$ 996,289	$ 915,436	$ 1,787,973	$ 1,649,396
Gross profit (loss)	274,094	247,431	421,160	392,681
Corporate
Product Information [Line Items]
Gross profit (loss)	314	(1,549)	(125)	(5,571)
Building Materials Business \| Operating Segments
Product Information [Line Items]
Net sales	931,735	856,570	1,660,157	1,531,025
Gross profit (loss)	250,156	227,260	375,346	353,534
Building Materials Business \| Operating Segments \| Interproduct Sales
Product Information [Line Items]
Net sales	(99,538)	(81,191)	(165,162)	(135,145)
Magnesia Specialties \| Operating Segments
Product Information [Line Items]
Net sales	64,554	58,866	127,816	118,371
Gross profit (loss)	23,624	21,720	45,939	44,718
Aggregates \| Building Materials Business \| Operating Segments \| Reportable Subsegments
Product Information [Line Items]
Net sales	578,388	547,293	1,029,767	978,153
Gross profit (loss)	173,487	165,044	252,765	247,080
Ready Mixed Concrete \| Building Materials Business \| Operating Segments \| Reportable Subsegments
Product Information [Line Items]
Net sales	241,894	214,947	464,275	401,799
Gross profit (loss)	26,863	25,301	46,655	43,200
Asphalt and Paving
Product Information [Line Items]
Net sales	111,975	88,081	138,577	101,918
Gross profit (loss)	20,358	12,867	15,568	6,591
Cement \| Building Materials Business \| Operating Segments \| Reportable Subsegments
Product Information [Line Items]
Net sales	99,016	87,440	192,700	184,300
Gross profit (loss)	$ 29,448	$ 24,048	$ 60,358	$ 56,663

Other Operating Income, Net - Additional Information (Detail) - Other Operating Income, Net	3 Months Ended
	Jun. 30, 2017 USD ($)
Component Of Other Income And Expense [Line Items]
Gain on sale of real estate	$ 13,500,000
Chief Financial Officer
Component Of Other Income And Expense [Line Items]
Retirement related expense including both cash and stock-based compensation	$ 6,100,000

Components of Change in Other Assets and Liabilities Net (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Supplemental Cash Flow Elements [Abstract]
Other current and noncurrent assets	$ (32,332)	$ (9,691)
Accrued salaries, benefits and payroll taxes	(7,892)	(7,808)
Accrued insurance and other taxes	(134)	(256)
Accrued income taxes	28,047	(8,495)
Accrued pension, postretirement and postemployment benefits	11,521	11,757
Other current and noncurrent liabilities	30,740	(5,477)
Change in other assets and liabilities, net	$ 29,950	$ (19,970)

Schedule Of Noncash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Supplemental Cash Flow Elements [Abstract]
Accrued liabilities for purchases of property, plant and equipment	$ 34,714	$ 33,959
Acquisition of assets through capital lease	149
Settlement of royalty obligation via asset sale	$ 900

Supplemental Disclosures of Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 38,111	$ 36,630
Cash paid for income taxes	$ 33,264	$ 47,159

Business Combinations - Additional Information (Detail)	3 Months Ended
Business Combinations - Additional Information (Detail)	Sep. 30, 2016 USD ($)	Mar. 31, 2016 T	Jul. 31, 2016
Colorado \| Minimum
Business Combinations [Line Items]
Acquisition of mineral reserves \| T		500,000,000
Central Texas \| Ratliff
Business Combinations [Line Items]
Ownership interest percentage under equity method, prior to acquisition			40.00%
Gain resulting from re-measurement of existing interest to fair value upon closing of transaction \| $	$ 5,863,000

Pending Acquisition of Bluegrass Materials - Additional Information (Detail)	Jun. 26, 2017 USD ($)
Bluegrass Materials Company
Business Combinations [Line Items]
Business acquisition agreed amount to acquire	$ 1,625,000,000