Martin Marietta Materials (MLM) 10-Q 7 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	MLM
Entity Registrant Name	MARTIN MARIETTA MATERIALS INC
Entity Central Index Key	916,076
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		62,712,073

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Current Assets:
Cash and cash equivalents	$ 53,961	$ 1,446,364	$ 35,219
Accounts receivable, net	644,835	487,240	582,532
Inventories, net	651,295	600,591	576,429
Other current assets	104,717	96,965	83,809
Total Current Assets	1,454,808	2,631,160	1,277,989
Property, plant and equipment	8,183,412	6,498,067	6,375,813
Allowances for depreciation, depletion and amortization	(3,080,017)	(2,905,254)	(2,854,236)
Net property, plant and equipment	5,103,395	3,592,813	3,521,577
Goodwill	2,399,434	2,160,290	2,160,060
Operating permits, net	434,177	439,116	440,846
Other intangibles, net	74,799	67,233	63,740
Other noncurrent assets	121,558	101,899	102,573
Total Assets	9,588,171	8,992,511	7,566,785
Current Liabilities:
Bank overdraft			1,047
Accounts payable	191,381	183,638	163,597
Accrued salaries, benefits and payroll taxes	45,234	44,255	37,885
Pension and postretirement benefits	9,292	13,652	12,073
Accrued insurance and other taxes	69,513	64,958	70,323
Current maturities of long-term debt and short-term facilities	380,041	299,909	80,038
Accrued interest	31,708	19,825	28,082
Other current liabilities	45,517	67,979	75,458
Total Current Liabilities	772,686	694,216	468,503
Long-term debt	2,829,657	2,727,294	1,642,502
Pension, postretirement and postemployment benefits	108,454	244,043	230,212
Deferred income taxes, net	692,881	410,723	662,982
Other noncurrent liabilities	242,165	233,758	228,604
Total Liabilities	4,645,843	4,310,034	3,232,803
Equity:
Common stock, par value $0.01 per share	626	628	627
Preferred stock, par value $0.01 per share
Additional paid-in capital	3,391,133	3,368,007	3,362,744
Accumulated other comprehensive loss	(121,491)	(129,104)	(122,928)
Retained earnings	1,669,126	1,440,069	1,090,778
Total Shareholders' Equity	4,939,394	4,679,600	4,331,221
Noncontrolling interests	2,934	2,877	2,761
Total Equity	4,942,328	4,682,477	4,333,982
Total Liabilities and Equity	$ 9,588,171	$ 8,992,511	$ 7,566,785

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
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 Earn

Consolidated Statements of Earnings and Comprehensive Earnings (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Total Revenues	$ 1,219,640	$ 1,087,732	$ 3,224,047	$ 2,995,116
Total Cost of Revenues	906,656	796,054	2,484,754	2,282,278
Gross Profit	312,984	291,678	739,293	712,838
Selling, general & administrative expenses	68,441	57,219	209,632	195,127
Acquisition-related expenses, net	89	1,314	12,925	3,319
Other operating expenses (income), net	3,792	6,181	(26,960)	(2,575)
Earnings from Operations	240,662	226,964	543,696	516,967
Interest expense	35,468	23,141	103,526	68,037
Other nonoperating income, net	(4,248)	(479)	(19,873)	(6,434)
Earnings before income tax expense	209,442	204,302	460,043	455,364
Income tax expense	29,089	52,763	84,147	119,277
Consolidated net earnings	180,353	151,539	375,896	336,087
Less: Net earnings (loss) attributable to noncontrolling interests	132	(7)	275	(72)
Net Earnings Attributable to Martin Marietta Materials, Inc.	180,221	151,546	375,621	336,159
Consolidated Comprehensive Earnings: (See Note 1)
Earnings attributable to Martin Marietta Materials, Inc.	184,613	154,524	383,234	343,918
Earnings (Loss) attributable to noncontrolling interests	132	1	276	(62)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 184,745	$ 154,525	$ 383,510	$ 343,856
Net Earnings Attributable to Martin Marietta Materials, Inc. Per Common Share:
Basic attributable to common shareholders	$ 2.86	$ 2.40	$ 5.95	$ 5.33
Diluted attributable to common shareholders	$ 2.85	$ 2.39	$ 5.93	$ 5.30
Weighted-Average Common Shares Outstanding:
Basic	62,932	62,896	62,970	62,940
Diluted	63,167	63,158	63,224	63,218
Cash Dividends Per Common Share	$ 0.48	$ 0.44	$ 1.36	$ 1.28
Products and Services
Total Revenues	$ 1,142,218	$ 1,022,487	$ 3,024,300	$ 2,811,646
Total Cost of Revenues	828,110	730,459	2,282,159	2,097,272
Freight
Total Revenues	77,422	65,245	199,747	183,470
Total Cost of Revenues	$ 78,546	$ 65,595	$ 202,595	$ 185,006

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows from Operating Activities:
Consolidated net earnings	$ 375,896	$ 336,087
Adjustments to reconcile consolidated net earnings to net cash provided by operating activities:
Depreciation, depletion and amortization	253,200	221,418
Stock-based compensation expense	23,084	23,698
Gain on divestitures and sales of assets	(35,167)	(17,970)
Deferred income taxes	68,833	6,543
Other items, net	(2,107)	(9,894)
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable, net	(132,176)	(124,622)
Inventories, net	(8,015)	(54,804)
Accounts payable	42,995	3,182
Other assets and liabilities, net	(145,005)	34,484
Net Cash Provided by Operating Activities	441,538	418,122
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(262,155)	(308,745)
Acquisitions, net	(1,640,698)	(7,200)
Proceeds from divestitures and sales of assets	63,460	33,138
Payment of railcar construction advances	(56,033)	(42,954)
Reimbursement of railcar construction advances	56,033	40,930
Investments in life insurance contracts, net	771	276
Net Cash Used for Investing Activities	(1,838,622)	(284,555)
Cash Flows from Financing Activities:
Borrowings of debt	875,000	1,011,244
Repayments of debt	(695,039)	(975,035)
Payments of deferred acquisition consideration	(6,707)
Payments on capital lease obligations	(2,589)	(2,708)
Debt issuance costs	(3,194)	(1,989)
Change in bank overdraft		1,047
Contributions by owners of noncontrolling interest		211
Dividends paid	(86,190)	(80,961)
Proceeds from exercise of stock options	6,993	10,017
Shares withheld for employees' income tax obligations	(10,416)	(10,213)
Purchase of remaining interest in existing joint venture	(12,800)
Repurchases of common stock	(60,377)	(99,999)
Net Cash Provided by (Used for) Financing Activities	4,681	(148,386)
Net Decrease in Cash and Cash Equivalents	(1,392,403)	(14,819)
Cash and Cash Equivalents, beginning of period	1,446,364	50,038
Cash and Cash Equivalents, end of period	$ 53,961	$ 35,219

Consolidated Statements of Tota

Consolidated Statements 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, 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	336,087				336,159	336,159	(72)
Other comprehensive earnings, net of tax	7,769			7,759		7,759	10
Dividends declared	(80,961)				(80,961)	(80,961)
Issuances of common stock for stock award plans	14,800	$ 2	14,798			14,800
Issuances of common stock for stock award plans (in shares)		141
Shares withheld for employees' income tax obligations	(10,213)		(10,213)			(10,213)
Repurchases of common stock	(99,999)	$ (5)			(99,994)	(99,999)
Repurchases of common stock, (in shares)		(458)
Stock-based compensation expense	23,698		23,698			23,698
Contributions by owners of noncontrolling interest	211						211
Ending Balance at Sep. 30, 2017	4,333,982	$ 627	3,362,744	(122,928)	1,090,778	4,331,221	2,761
Ending Balance (in shares) at Sep. 30, 2017		62,859
Beginning Balance at Jun. 30, 2017				(125,906)
Consolidated net earnings	151,539
Ending Balance at Sep. 30, 2017	4,333,982	$ 627	3,362,744	(122,928)	1,090,778	4,331,221	2,761
Ending Balance (in shares) at Sep. 30, 2017		62,859
Beginning Balance at Dec. 31, 2017	4,682,477	$ 628	3,368,007	(129,104)	1,440,069	4,679,600	2,877
Beginning Balance (in shares) at Dec. 31, 2017		62,873
Consolidated net earnings	375,896				375,621	375,621	275
Other comprehensive earnings, net of tax	7,614			7,613		7,613	1
Dividends declared	(86,190)				(86,190)	(86,190)
Issuances of common stock for stock award plans	14,039	$ 1	14,038			14,039
Issuances of common stock for stock award plans (in shares)		144
Shares withheld for employees' income tax obligations	(10,416)		(10,416)			(10,416)
Repurchases of common stock	(60,377)	$ (3)			(60,374)	(60,377)
Repurchases of common stock, (in shares)		(305)
Stock-based compensation expense	23,084		23,084			23,084
Noncontrolling interest acquired in business combination	9,001						9,001
Purchase of remaining interest in existing joint venture	(12,800)		(3,580)			(3,580)	(9,220)
Ending Balance at Sep. 30, 2018	4,942,328	$ 626	3,391,133	(121,491)	1,669,126	4,939,394	2,934
Ending Balance (in shares) at Sep. 30, 2018		62,712
Beginning Balance at Jun. 30, 2018				(125,883)
Consolidated net earnings	180,353
Ending Balance at Sep. 30, 2018	$ 4,942,328	$ 626	$ 3,391,133	$ (121,491)	$ 1,669,126	$ 4,939,394	$ 2,934
Ending Balance (in shares) at Sep. 30, 2018		62,712

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	1. Significant Accounting Policies Organization Martin Marietta Materials, Inc. (the Company or Martin Marietta) is a natural resource-based building materials company. The Company supplies aggregates (crushed stone, sand and gravel) through its network of more than 300 quarries, mines and distribution yards to its customers in 30 states, Canada, the Bahamas and the Caribbean Islands. In the western United States, Martin Marietta also provides cement and downstream products, namely, ready mixed concrete, asphalt and paving services, in vertically-integrated structured markets where the Company has a leading aggregates position. The Company’s heavy-side building materials are used in infrastructure, nonresidential and residential construction projects. Aggregates are also used in agricultural, utility and environmental applications and as railroad ballast. The aggregates, cement, ready mixed concrete and asphalt and paving product lines are reported collectively as the “Building Materials” business. 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, Pennsylvania, South Carolina, Virginia, Washington and West Virginia Alabama, Florida, Georgia, Tennessee, Arkansas, Colorado, southern Kansas, Louisiana, western Nebraska, Nevada, Oklahoma, Texas, Utah and Wyoming Product Lines Aggregates Aggregates Aggregates, Cement, Ready Mixed Concrete, Asphalt and Paving The Company has a Magnesia Specialties business with manufacturing facilities in Manistee, Michigan, and Woodville, Ohio. The Magnesia Specialties business produces magnesia-based chemicals products used in industrial, agricultural and environmental applications, and dolomitic lime sold primarily to customers in the steel and mining industries. 1. Significant Accounting Policies (continued) Basis of Presentation The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP) 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 required adoption of two new accounting pronouncements 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, 2017. 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 three- and nine-months ended September 30, 2018 are not indicative of the results expected for other interim periods or the full year. The consolidated balance sheet at December 31, 2017 has been derived from the audited consolidated financial statements at that date but does not include all of the information and notes required by U.S. GAAP 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, 2017. New Accounting Pronouncements Revenue from Contracts with Customers Effective January 1, 2018, the Company adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments Effective January 1, 2018, the Company adopted ASU 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments 1. Significant Accounting Policies (continued) Pending Accounting Pronouncement Lease Standard In February 2016, the Financial Accounting Standards Board (FASB) issued a new accounting standard, Accounting Standards Codification 842 – Leases , The new standard provides a number of practical expedients for transition and policy elections for ongoing accounting. The Company expects to elect the “package of practical expedients”, which permits the Company to not reassess its prior conclusions about lease identification, lease classification and initial direct costs. The Company plans to elect the practical expedients pertaining to the use of hindsight and to land easements. The standard provides policy election options for recognition exemption for short-term leases and separation of lease and non-lease components. The Company will elect the short-term lease recognition exemption and expects to elect not to separate lease and non-lease components for all underlying asset classes with the exceptions of railcars and fleet leases. Although the Company has not determined the full impact of ASC 842, the Company expects the adoption of ASC 842 to have a material impact on its financial statements, specifically right-to-use assets and lease liabilities on the balance sheet and note disclosures pertaining to leasing activities. 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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Net earnings attributable to Martin Marietta Materials, Inc. $ 180,221 $ 151,546 $ 375,621 $ 336,159 Other comprehensive earnings, net of tax 4,392 2,978 7,613 7,759 Comprehensive earnings attributable to Martin Marietta Materials, Inc. $ 184,613 $ 154,524 $ 383,234 $ 343,918 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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Net earnings (loss) attributable to noncontrolling interests $ 132 $ (7 ) $ 275 $ (72 ) Other comprehensive earnings, net of tax — 8 1 10 Comprehensive earnings (loss) attributable to noncontrolling interests $ 132 $ 1 $ 276 $ (62 ) 1. Significant Accounting Policies (continued) Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss (continued) Changes in accumulated other comprehensive earnings, 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 September 30, 2018 Balance at beginning of period $ (124,798 ) $ (1,085 ) $ — $ (125,883 ) Other comprehensive earnings before reclassifications, net of tax — 365 — 365 Amounts reclassified from accumulated other comprehensive loss, net of tax 4,027 — — 4,027 Other comprehensive earnings, net of tax 4,027 365 — 4,392 Balance at end of period $ (120,771 ) $ (720 ) $ — $ (121,491 ) Three-Months Ended September 30, 2017 Balance at beginning of period $ (124,553 ) $ (636 ) $ (717 ) $ (125,906 ) Other comprehensive earnings before reclassifications, net of tax — 838 — 838 Amounts reclassified from accumulated other comprehensive loss, net of tax 1,918 — 222 2,140 Other comprehensive earnings, net of tax 1,918 838 222 2,978 Balance at end of period $ (122,635 ) $ 202 $ (495 ) $ (122,928 ) 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 Nine-Months Ended September 30, 2018 Balance at beginning of period $ (128,802 ) $ (22 ) $ (280 ) $ (129,104 ) Other comprehensive loss before reclassifications, net of tax — (698 ) — (698 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 8,031 — 280 8,311 Other comprehensive earnings (loss), net of tax 8,031 (698 ) 280 7,613 Balance at end of period $ (120,771 ) $ (720 ) $ — $ (121,491 ) Nine-Months Ended September 30, 2017 Balance at beginning of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Other comprehensive earnings before reclassifications, net of tax — 1,364 — 1,364 Amounts reclassified from accumulated other comprehensive loss, net of tax 5,738 — 657 6,395 Other comprehensive earnings, net of tax 5,738 1,364 657 7,759 Balance at end of period $ (122,635 ) $ 202 $ (495 ) $ (122,928 ) 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 September 30, 2018 Balance at beginning of period $ 78,619 $ — $ 78,619 Tax effect of other comprehensive earnings (1,326 ) — (1,326 ) Balance at end of period $ 77,293 $ — $ 77,293 Three-Months Ended September 30, 2017 Balance at beginning of period $ 79,675 $ 464 $ 80,139 Tax effect of other comprehensive earnings (1,193 ) (147 ) (1,340 ) Balance at end of period $ 78,482 $ 317 $ 78,799 Nine-Months Ended September 30, 2018 Balance at beginning of period $ 79,938 $ 178 $ 80,116 Tax effect of other comprehensive earnings (2,645 ) (178 ) (2,823 ) Balance at end of period $ 77,293 $ — $ 77,293 Nine-Months Ended September 30, 2017 Balance at beginning of period $ 82,044 $ 749 $ 82,793 Tax effect of other comprehensive earnings (3,562 ) (432 ) (3,994 ) Balance at end of period $ 78,482 $ 317 $ 78,799 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 Nine-Months Ended Affected line items in the consolidated September 30, September 30, statements of earnings and 2018 2017 2018 2017 comprehensive earnings (Dollars in Thousands) Pension and postretirement benefit plans Settlement expense $ 2,692 $ — $ 2,692 $ — Amortization of: Prior service credit (492 ) (402 ) (1,479 ) (1,070 ) Actuarial loss 3,153 3,513 9,463 10,370 5,353 3,111 10,676 9,300 Other nonoperating income, net Tax benefit (1,326 ) (1,193 ) (2,645 ) (3,562 ) Income tax expense $ 4,027 $ 1,918 $ 8,031 $ 5,738 Unamortized value of terminated forward starting interest rate swap Additional interest expense $ — $ 369 $ 458 $ 1,089 Interest expense Tax benefit — (147 ) (178 ) (432 ) Income tax expense $ — $ 222 $ 280 $ 657 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 nine-months ended September 30, 2018 and 2017, the diluted per-share computations reflect 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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (In Thousands) Net earnings attributable to Martin Marietta Materials, Inc. $ 180,221 $ 151,546 $ 375,621 $ 336,159 Less: Distributed and undistributed earnings attributable to unvested awards 271 399 672 1,000 Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc. $ 179,950 $ 151,147 $ 374,949 $ 335,159 Basic weighted-average common shares outstanding 62,932 62,896 62,970 62,940 Effect of dilutive employee and director awards 235 262 254 278 Diluted weighted-average common shares outstanding 63,167 63,158 63,224 63,218

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Revenue Recognition	2. Revenue Recognition Total revenues include sales of products and services to customers, net of any discounts or allowances, and freight revenues. Product revenues are recognized when control of the promised good is transferred to the customer, typically when finished products are shipped. Intersegment and interproduct revenues are eliminated in consolidation. Service revenues are derived from the paving business and recognized using the percentage-of-completion method under the revenue-cost approach. Under the revenue-cost approach, recognized contract revenue is determined by multiplying the total estimated contract revenue by the estimated percentage of completion. Contract costs are recognized as incurred. The percentage of completion is determined on a contract-by-contract basis using project costs incurred to date as a percentage of total estimated project costs. The Company believes the revenue-cost approach is appropriate as the use of asphalt in a paving contract is relatively consistent with the performance of the paving service. Paving contracts, notably with governmental entities, may contain performance bonuses based on quality specifications. Given the uncertainty of meeting the criteria until the performance obligation is completed, performance bonuses are recognized as revenues when and if determined to be achieved. Performance bonuses are not material to the Company’s consolidated results of operations for the three- and nine-months ended September 30, 2018 and 2017. Freight revenues reflect delivery arranged by the Company using a third party on behalf of the customer and are recognized consistent with the timing of the product revenues. 2. Revenue Recognition (continued) Performance Obligations. Performance obligations are contractual promises to transfer or provide a distinct good or service for a stated price. The Company’s product sales agreements are single-performance obligations that are satisfied at a point in time. Performance obligations within paving service agreements are satisfied over time, primarily ranging from one day to 20 months. For product revenues and freight revenues, customer payment terms are generally 30 days from invoice date. Customer payments for the paving operations are based on a contractual billing schedule and are due 30 days from invoice date. Future revenues from unsatisfied performance obligations at September 30, 2018 and 2017 were $111,721,000 and $107,953,000, respectively, where the remaining periods to complete these obligations ranged from one month to 27 months and one month to 21 months, respectively. Sales Taxes. The Company is deemed to be an agent when collecting sales taxes from customers. Sales taxes collected are initially recorded as liabilities until remitted to taxing authorities and are not reflected in the consolidated statements of earnings as revenues and expenses. Revenue by Category. The following table presents the Company’s total revenues by category for each reportable segment: Three-Months Ended September 30, 2018 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 348,429 $ 28,576 $ 377,005 Southeast Group 121,661 3,886 125,547 West Group 603,763 39,802 643,565 Total Building Materials Business 1,073,853 72,264 1,146,117 Magnesia Specialties 68,365 5,158 73,523 Total $ 1,142,218 $ 77,422 $ 1,219,640 Three-Months Ended September 30, 2017 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 287,085 $ 21,387 $ 308,472 Southeast Group 91,427 3,416 94,843 West Group 584,086 36,426 620,512 Total Building Materials Business 962,598 61,229 1,023,827 Magnesia Specialties 59,889 4,016 63,905 Total $ 1,022,487 $ 65,245 $ 1,087,732 Service revenues, which include paving operations located in Colorado, were $82,232,000 and $94,503,000 for the three-months ended September 30, 2018 and 2017, respectively. 2. Revenue Recognition (continued) Nine-Months Ended September 30, 2018 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 841,897 $ 64,480 $ 906,377 Southeast Group 308,306 10,443 318,749 West Group 1,672,707 110,467 1,783,174 Total Building Materials Business 2,822,910 185,390 3,008,300 Magnesia Specialties 201,390 14,357 215,747 Total $ 3,024,300 $ 199,747 $ 3,224,047 Nine-Months Ended September 30, 2017 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 734,406 $ 53,984 $ 788,390 Southeast Group 266,690 10,784 277,474 West Group 1,620,632 106,110 1,726,742 Total Building Materials Business 2,621,728 170,878 2,792,606 Magnesia Specialties 189,918 12,592 202,510 Total $ 2,811,646 $ 183,470 $ 2,995,116 Services revenues, which include paving operations located in Colorado, were $162,944,000 and $179,553,000 for the nine-months ended September 30, 2018 and 2017, respectively. Contract Balances. Costs in excess of billings relate to the conditional right to consideration for completed contractual performance and are contract assets on the consolidated balance sheets. Costs in excess of billings are reclassified to accounts receivable when the right to consideration becomes unconditional. Billings in excess of costs relate to customers invoiced in advance of contractual performance and are contract liabilities on the consolidated balance sheets. The following table presents information about the Company’s contract balances: (Dollars in Thousands) September 30, 2018 December 31, 2017 September 30, 2017 Costs in excess of billings $ 5,581 $ 1,310 $ 8,727 Billings in excess of costs $ 9,111 $ 7,204 $ 5,981 2. Revenue Recognition (continued) Revenues recognized from the beginning balance of contract liabilities for the three-months ended September 30, 2018 and 2017 were $6,203,000 and $4,439,000, respectively, and for the nine-months ended September 30, 2018 and 2017 were $6,816,000 and $8,231,000, respectively. Retainage, which primarily relates to the paving services, represents amounts that have been billed to customers but payment withheld until final acceptance of the performance obligation by the customer. Included on the Company’s consolidated balance sheets, retainage was $8,733,000, $9,029,000 and $7,680,000 at September 30, 2018, December 31, 2017 and September 30, 2017, respectively. Warranties. The Company’s construction contracts generally contain warranty provisions typically for a period of nine months to one year after project completion and cover materials, design or workmanship defects. Historically, the Company has not experienced material costs for warranties. The ready mixed concrete product line carries longer warranty periods, for which the Company has accrued an estimate of warranty cost based on experience with the type of work and any known risks relative to the project. In total, warranty costs were not material to the Company’s consolidated results of operations for the three- and nine-months ended September 30, 2018 and 2017. Policy Elections. When the Company arranges third party freight to deliver products to customers, the Company has elected the delivery to be a fulfillment activity rather than a separate performance obligation. Further, the Company acts as a principal in the delivery arrangements and, as required by the accounting standard, the related revenues and costs are presented gross and are included in the consolidated statements of earnings.

Business Combination

Business Combination	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Business Combination	3. Business Combination On April 27, 2018, the Company successfully completed its acquisition of Bluegrass Materials Company (Bluegrass), the largest privately-held, pure-play aggregates company in the United States. The final purchase price was $1,617,357,000, inclusive of the working capital true up. Bluegrass’ operations include 23 active sites with more than 125 years of reserves, collectively, in Georgia, South Carolina, Tennessee, Maryland, Kentucky and Pennsylvania. These operations complement the Company’s existing southeastern footprint in its Mid-America and Southeast Groups and provide new growth platforms within Maryland and Kentucky. The Company reached an agreement with the U.S. Department of Justice (DOJ), approved by the federal district court for the District of Columbia, which resolved all competition issues with respect to the acquisition. Under the terms of the agreement with the DOJ, Martin Marietta divested its heritage Forsyth aggregates quarry north of Atlanta, Georgia, and the legacy Bluegrass Beaver Creek aggregates quarry in western Maryland. In connection with the sale of its Forsyth quarry, t he Company recognized a pretax gain of $14,785,000, which is included in acquisition-related expenses, net, in the consolidated statements of earnings and comprehensive earnings. There was no gain or loss on the Beaver Creek divestiture. The Bluegrass acquisition was a stock transaction wherein the Company acquired 100% of the voting interest of the owners. The Company acquired accounts receivable; inventories; property, plant and equipment, which primarily consists of mineral reserves; intangible assets; prepaid and other assets; and assumed accounts payable; accrued liabilities and deferred tax liabilities, net. The Company did not assume any of Bluegrass’ outstanding debt. 3. Business Combination (continued) The Company has determined preliminary fair values of the assets acquired and liabilities assumed. Although initial accounting for the business combination has been recorded, these amounts are subject to change during the measurement period which extends no longer than one year from consummation date based on additional reviews, such as asset verification and completion of deferred tax estimates based on the determination of the historic tax basis in assets acquired. Specific accounts subject to ongoing purchase accounting adjustments include, but are not limited to, property, plant and equipment; goodwill; and deferred income tax liabilities. Therefore, the measurement period remains open as of September 30, 2018. The following is a summary of the estimated fair values of the assets acquired and the liabilities assumed (dollars in thousands). Assets: Cash $ 1,159 Receivables 25,479 Inventory 46,156 Other current assets 1,029 Property, plant and equipment 1,522,386 Intangible assets, other than goodwill 19,125 Goodwill 239,360 Total assets 1,854,694 Liabilities: Accounts payable and accrued expenses 17,893 Deferred income tax liabilities, net 210,443 Noncontrolling interest 9,001 Total liabilities 237,337 Total consideration $ 1,617,357 Goodwill represents the excess purchase price over the fair values of assets acquired and liabilities assumed and reflects projected operating synergies from the transaction, including expected overhead savings. It has not yet been determined if any of the goodwill generated by the transaction will be deductible for income tax purposes. Total revenues and earnings from operations attributable to acquired operations included in the consolidated earnings statements for the three-months ended September 30, 2018 were $68,656,000 and $11,531,000, respectively, and for the nine-months ended September 30, 2018 were $115,007,000 and $18,276,000, respectively. Acquisition-related expenses were $89,000 and $27,710,000 for the three- and nine-months ended September 30, 2018, respectively. 3. Business Combination (continued) Unaudited Pro Forma Financial Information The unaudited pro forma financial information in the table below summarizes the combined results of operations for the Company and Bluegrass as though the companies were combined as of January 1, 2017. Financial information for periods prior to the April 27, 2018 acquisition date included in the pro forma earnings does not reflect any cost savings or associated costs to achieve such savings from operating efficiencies or synergies that result from the combination. Consistent with the assumed acquisition date of January 1, 2017, the pro forma financial results for the nine-months ended September 30, 2017 include acquisition-related expenses of $27,710,000, the $14,785,000 gain on the required divestiture of assets and the one-time $19,893,000 increase in cost of sales for the sale of acquired inventory. The pro forma financial statements do not purport to project the future financial position or operating results of the combined company. The pro forma financial information as presented below is for informational purposes only and is not indicative of the results of operations that would have been achieved if the acquisition had taken place at the beginning of fiscal year 2017. Three-Months Ended Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands, except per share data) Total revenues $ 1,219,640 $ 1,148,787 $ 3,279,455 $ 3,154,563 Net earnings attributable to Martin Marietta $ 185,051 $ 151,986 $ 399,113 $ 300,458 Diluted EPS $ 2.93 $ 2.41 $ 6.31 $ 4.75 On August 31, 2018, the Company purchased the remaining noncontrolling interest in a consolidated joint venture where the initial controlling interest was acquired as part of the Bluegrass acquisition.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	4. Goodwill and Other Intangibles Mid-America Southeast West Group Group Group Total (Dollars in Thousands) Balance at January 1, 2018 $ 281,403 $ 50,346 $ 1,828,541 $ 2,160,290 Acquisitions 147,333 92,738 — 240,071 Divestitures — (927 ) — (927 ) Balance at September 30, 2018 $ 428,736 $ 142,157 $ 1,828,541 $ 2,399,434 4. Goodwill and Other Intangibles (continued) Intangible assets subject to amortization consist of the following: Gross Amount Accumulated Amortization Net Balance (Dollars in Thousands) September 30, 2018 Noncompetition agreements $ 12,024 $ (11,105 ) $ 919 Customer relationships 56,530 (18,325 ) 38,205 Operating permits 458,952 (31,375 ) 427,577 Use rights and other 19,564 (10,789 ) 8,775 Trade names 12,800 (9,387 ) 3,413 Total $ 559,870 $ (80,981 ) $ 478,889 Intangible assets deemed to have an indefinite life and not being amortized consist of the following: Building Materials Business Magnesia Specialties Total (Dollars in Thousands) September 30, 2018 Operating permits $ 6,600 $ — $ 6,600 Use rights 20,642 — 20,642 Trade names 280 2,565 2,845 Total $ 27,522 $ 2,565 $ 30,087 Intangibles acquired during the year are as follows: (Dollars in Thousands) Amount Weighted-average amortization period Subject to amortization: Customer relationships $ 20,620 12 years Not subject to amortization: Water rights 1,100 N/A Total $ 21,720 4. Goodwill and Other Intangibles (continued) Total amortization expense for intangible assets for the nine-months ended September 30, 2018 and 2017 was $10,549,000 and $10,710,000, respectively. The estimated amortization expense for intangible assets for the last three months of 2018 and for each of the next four years and thereafter is as follows: (Dollars in Thousands) October - December 2018 $ 3,398 2019 13,429 2020 13,393 2021 12,703 2022 11,232 Thereafter 424,734 Total $ 478,889

Inventories, Net

Inventories, Net	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Inventories, Net	5. Inventories, Net September 30, December 31, September 30, 2018 2017 2017 (Dollars in Thousands) Finished products $ 610,663 $ 552,999 $ 526,404 Products in process and raw materials 61,891 62,761 62,449 Supplies and expendable parts 139,409 128,792 126,918 811,963 744,552 715,771 Less: Allowances (160,668 ) (143,961 ) (139,342 ) Total $ 651,295 $ 600,591 $ 576,429

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-Term Debt	6. Long-Term Debt September 30, December 31, September 30, 2018 2017 2017 (Dollars in Thousands) 6.60% Senior Notes, due 2018 $ — $ 299,871 $ 299,774 7% Debentures, due 2025 124,249 124,180 124,157 6.25% Senior Notes, due 2037 228,079 228,033 228,018 4.25% Senior Notes, due 2024 396,251 395,814 395,673 4.250% Senior Notes, due 2047 591,499 591,688 — 3.500% Senior Notes, due 2027 494,643 494,352 — 3.450% Senior Notes, due 2027 296,861 296,628 296,551 Floating Rate Senior Notes, due 2019, interest rate of 2.84% and 2.13% at September 30, 2018 and December 31, 2017, respectively 299,074 298,102 — Floating Rate Notes, due 2020, interest rate of 2.96%, 2.10% and 1.96% at September 30, 2018, December 31, 2017 and September 30, 2017, respectively 298,773 298,227 298,046 Revolving Facility, due 2022, interest rate of 3.29% at September 30, 2018 100,000 — — Trade Receivable Facility, interest rate of 2.83% and 1.96% at September 30, 2018 and 2017, respectively 380,000 — 80,000 Other notes 269 308 321 Total debt 3,209,698 3,027,203 1,722,540 Less: Current maturities of long-term debt and short-term facilities (380,041 ) (299,909 ) (80,038 ) Long-term debt $ 2,829,657 $ 2,727,294 $ 1,642,502 On April 17, 2018, t he , through a wholly-owned special-purpose subsidiary, increased its trade receivable securitization facility (the Trade Receivable Facility) to $400,000,000. 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 $465,217,000, $338,784,000 and $402,754,000 at September 30, 2018, December 31, 2017 and September 30, 2017, respectively. These receivables are originated by the and then sold to the wholly-owned special-purpose subsidiary by the . The con tinues to be responsible for the servicing and administration of the receivables purchased by the wholly-owned special-purpose . Borrowings under the Trade Receivable Facility bear interest at a rate equal to one-month London Inter-bank Offered Rate, or LIBOR, plus 0.725%, subject to change in the event that this rate no longer reflects the lender’s cost of lending . On September 25, 2018, the Company extended t maturity date of to September 25, 2019 On April 16, 2018, the maturity date, the Company repaid the $300,000,000 of the 6.6% Senior Notes with cash on hand. 6. Long-Term Debt (continued) 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 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 September 30, 2018. Available borrowings under the Revolving Facility are reduced by any outstanding letters of credit issued by the Company under the Revolving Facility. The Company had $2,301,000 of outstanding letters of credit issued under the Revolving Facility at September 30, 2018 and December 31, 2017 and $1,963,000 at September 30, 2017. Accumulated other comprehensive loss includes the unamortized value of terminated forward starting interest rate swap agreements. The amortization of the terminated value of the forward starting interest rate swap agreements was complete with the maturity of the related debt in April 2018. For the nine-months ended September 30, 2018, the Company recognized $458,000 as additional interest expense. For the three- and nine-months ended September 30, 2017, the Company recognized $369,000 and $1,089,000, respectively, as additional interest expense.

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2018
Financial Instruments Disclosure [Abstract]
Financial Instruments	7 . Financial Instruments The Company’s financial instruments include cash equivalents, accounts receivable, notes receivable, bank overdrafts, 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. Bank overdrafts, when applicable, represent amounts to be funded to financial institutions for checks that have cleared the bank. The estimated fair value of bank overdrafts 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. 7. Financial Instruments (continued) The carrying values and fair values of the Company’s long-term debt were $3,209,698,000 and $3,144,615,000, respectively, at September 30, 2018; $3,027,203,000 and $3,144,902,000, respectively, at December 31, 2017; and $1,722,540,000 and $1,830,750,000, respectively, at September 30, 2017. 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

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes The Company’s effective income tax rate for the nine-months ended September 30, 2018 was 18.3%. The effective income tax rate reflects the effect of federal and state income taxes on earnings and the impact of differences in book and tax accounting arising from the net permanent tax benefits associated with the statutory depletion deduction for mineral reserves. For the nine-months ended September 30, 2018, the effective income tax rate also reflects a permanent net income tax benefit of $15,454,000 resulting primarily from (i) the Company making additional contributions of $125,000,000 for a total of $150,000,000 discretionary contributions to its qualified pension plan during the quarter ended September 30, 2018, which is deductible on the Company’s 2017 income tax return; and (ii) changes in the Company’s method of accounting for income tax purposes to accelerate the deduction of various expenses. Prior to the quarter ended September 30, 2018, the Company had included an estimate of $25,000,000 of discretionary pension plan contributions in its 2017 tax provision. The tax benefit resulted from the difference in the federal tax rate at which the deductions were claimed versus the tax rate at which the deferred tax assets were recorded at year end as a result of the Tax Reform Act (2017 Tax Act), net of the correlative effects of reduced deductions for domestic production deduction and percentage depletion. The enactment of the 2017 Tax Act reduced the federal statutory corporate income tax rate from 35% to 21% beginning in 2018. Therefore, the effective income tax rate of 26.2% for the nine-months ended September 30, 2017 is not comparable. The Securities and Exchange Commission issued Staff Accounting Bulletin No. 118 (SAB 118) to address situations when a registrant does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the 2017 Tax Act. As such, due to the timing of the enactment date and the Company’s reporting periods, the Company recognized provisional amounts for the remeasurement of deferred tax assets and liabilities, including the tax benefit mentioned above, and transition tax on undistributed foreign earnings as of September 30, 2018. In accordance with SAB 118, the Company may record additional provisional amounts during the measurement period not to extend beyond one year of the enactment date. The Company will complete its analysis after the filing of its federal and state corporate income tax returns in the fourth quarter. 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 Bene

Pension and Postretirement Benefits	9 Months Ended
	Sep. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Pension and Postretirement Benefits	9. 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 September 30, Pension Postretirement Benefits 2018 2017 2018 2017 (Dollars in Thousands) Service cost $ 7,911 $ 7,457 $ 19 $ 20 Interest cost 8,307 9,729 130 182 Expected return on assets (11,516 ) (10,691 ) — — Amortization of: Prior service cost (credit) 27 34 (519 ) (436 ) Actuarial loss (gain) 3,206 3,604 (53 ) (91 ) Settlement charge 2,692 — — — Net periodic benefit cost (credit) $ 10,627 $ 10,133 $ (423 ) $ (325 ) Nine-Months Ended September 30, Pension Postretirement Benefits 2018 2017 2018 2017 (Dollars in Thousands) Service cost $ 23,732 $ 20,060 $ 58 $ 60 Interest cost 24,921 27,074 389 547 Expected return on assets (34,549 ) (29,818 ) — — Amortization of: Prior service cost (credit) 77 237 (1,556 ) (1,307 ) Actuarial loss (gain) 9,621 10,643 (158 ) (273 ) Settlement charge 2,692 — — — Net periodic benefit cost (credit) $ 26,494 $ 28,196 $ (1,267 ) $ (973 ) The service cost component of net periodic benefit cost (credit) is included in cost of revenues – products and services and selling, general and administrative expenses while all other components are included in other nonoperating income, net, in the consolidated statements of earnings and comprehensive earnings. In the quarter ended September 30, 2018, the Company made $150,000,000 of discretionary contributions to its qualified pension plan. No additional contributions to the qualified pension plan are expected to be made for the remainder of 2018. The Company currently estimates that it will contribute a total of $12,400,000 for the year ending December 31, 2018 to satisfy required payments under the unfunded nonqualified pension plans.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. 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 $15,500,000 revolving line of credit agreement with BB&T with a maturity date of March 2020. 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 September 30, 2018, December 31, 2017 and September 30, 2017. The interest rate is one-month LIBOR plus 1.75%. Employees The Company maintains collective bargaining agreements relating to the union employees within the Building Materials business and Magnesia Specialties segment. Of the Magnesia Specialties segment, 100% of its hourly employees are represented by labor unions. The Manistee collective bargaining agreement expires in August 2019; the Woodville collective bargaining agreement expires June 2022.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Business Segments	11. 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 total revenues less cost of revenues; 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 loss from operations primarily includes depreciation on capitalized interest; unallocated expenses for corporate administrative functions; acquisition-related expenses, net; and other nonrecurring 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 the Company’s reportable business segments. The acquired Bluegrass operations are located in the Mid-America Group and Southeast Group. Total revenues, as well as the consolidated statements of earnings and comprehensive earnings, exclude intersegment revenues which represent sales from one segment to another segment, which are eliminated. Prior-year information has been reclassified to conform to current year revenue presentation. 11. Business Segments (continued) Three-Months Ended Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Total revenues Mid-America Group $ 377,005 $ 308,472 $ 906,377 $ 788,390 Southeast Group 125,547 94,843 318,749 277,474 West Group 643,565 620,512 1,783,174 1,726,742 Total Building Materials Business 1,146,117 1,023,827 3,008,300 2,792,606 Magnesia Specialties 73,523 63,905 215,747 202,510 Total $ 1,219,640 $ 1,087,732 $ 3,224,047 $ 2,995,116 Products and services revenues: Mid-America Group $ 348,429 $ 287,085 $ 841,897 $ 734,406 Southeast Group 121,661 91,427 308,306 266,690 West Group 603,763 584,086 1,672,707 1,620,632 Total Building Materials Business 1,073,853 962,598 2,822,910 2,621,728 Magnesia Specialties 68,365 59,889 201,390 189,918 Total $ 1,142,218 $ 1,022,487 $ 3,024,300 $ 2,811,646 Earnings (Loss) from operations Mid-America Group $ 120,344 $ 106,235 $ 235,221 $ 204,939 Southeast Group 26,372 17,882 60,464 42,331 West Group 92,090 96,522 249,885 270,246 Total Building Materials Business 238,806 220,639 545,570 517,516 Magnesia Specialties 23,301 17,590 65,867 58,589 Corporate (21,445 ) (11,265 ) (67,741 ) (59,138 ) Total $ 240,662 $ 226,964 $ 543,696 $ 516,967 September 30, 2018 December 31, 2017 September 30, 2017 Assets employed: (Dollars in thousands) Mid-America Group $ 2,802,054 $ 1,532,867 $ 1,538,594 Southeast Group 1,300,090 616,344 604,144 West Group 5,032,662 5,014,231 5,032,103 Total Building Materials Business 9,134,806 7,163,442 7,174,841 Magnesia Specialties 141,998 152,257 148,581 Corporate 311,367 1,676,812 243,363 Total $ 9,588,171 $ 8,992,511 $ 7,566,785

Revenues and Gross Profit

Revenues and Gross Profit	9 Months Ended
	Sep. 30, 2018
Revenues And Gross Profit [Abstract]
Revenues and Gross Profit	12. Revenues and Gross Profit 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 total revenues and gross profit by product line. Three-Months Ended Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Total revenues: Building Materials Business: Products and services: Aggregates $ 687,800 $ 590,312 $ 1,778,124 $ 1,619,282 Cement 98,223 88,470 300,554 280,961 Ready mixed concrete 254,686 240,222 750,424 704,471 Asphalt and paving services 99,983 110,973 199,489 215,652 Less: interproduct revenues (66,839 ) (67,379 ) (205,681 ) (198,638 ) Products and services 1,073,853 962,598 2,822,910 2,621,728 Freight 72,264 61,229 185,390 170,878 Total Building Materials Business 1,146,117 1,023,827 3,008,300 2,792,606 Magnesia Specialties: Products and services 68,365 59,889 201,390 189,918 Freight 5,158 4,016 14,357 12,592 Total Magnesia Specialties 73,523 63,905 215,747 202,510 Total $ 1,219,640 $ 1,087,732 $ 3,224,047 $ 2,995,116 Gross profit (loss) Building Materials Business: Products and services: Aggregates $ 209,082 $ 187,065 $ 460,624 $ 439,032 Cement 32,543 27,459 97,582 87,608 Ready mixed concrete 20,632 23,913 66,226 70,542 Asphalt and paving services 25,606 28,873 36,479 44,446 Products and services 287,863 267,310 660,911 641,628 Freight (47 ) 1,012 432 2,040 Total Building Materials Business 287,816 268,322 661,343 643,668 Magnesia Specialties: Products and services 26,823 21,272 76,756 69,425 Freight (1,076 ) (1,362 ) (3,280 ) (3,576 ) Total Magnesia Specialties 25,747 19,910 73,476 65,849 Corporate (579 ) 3,446 4,474 3,321 Total $ 312,984 $ 291,678 $ 739,293 $ 712,838

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	13. Supplemental Cash Flow Information The components of the change in other assets and liabilities, net, are as follows: Nine-Months Ended September 30, 2018 2017 (Dollars in Thousands) Other current and noncurrent assets $ (32,572 ) $ (29,342 ) Accrued salaries, benefits and payroll taxes 5,986 (6,234 ) Accrued insurance and other taxes 4,555 10,230 Accrued income taxes 6,220 16,393 Accrued pension, postretirement and postemployment benefits (131,963 ) (5,807 ) Other current and noncurrent liabilities 2,769 49,244 $ (145,005 ) $ 34,484 Noncash investing and financing activities are as follows: Nine-Months Ended September 30, 2018 2017 (Dollars in Thousands) Noncash investing and financing activities: Accrued liabilities for purchases of property, plant and equipment $ 24,930 $ 20,339 Acquisition of assets through capital lease $ 449 $ 196 Settlement of royalty obligation via asset sale $ — $ 900 Supplemental disclosures of cash flow information are as follows: Nine-Months Ended September 30, 2018 2017 (Dollars in Thousands) Cash paid for interest $ 84,522 $ 49,564 Cash paid for income taxes $ 7,253 $ 96,643

Other Operating Expenses and I

Other Operating Expenses and Income, Net	9 Months Ended
	Sep. 30, 2018
Other Income And Expenses [Abstract]
Other Operating Expenses and Income, Net	14. Other operating expenses and income, net Other operating expenses and income, net, for the quarter ended September 30, 2018, include a $7,113,000 restructuring charge, which primarily consists of asset impairment charges and severance costs in the Company’s Southwest ready mixed concrete operations. These operations are reported in the West Group reportable segment. For the nine-months ended September 30, 2018, in addition to the restructuring charge, other operating expenses and income, net, includes a net gain on legal settlements of $7,677,000 and a gain on the sale of surplus land of $16,938,000. Other operating expenses, net, for the quarter ended September 30, 2017 include $12,425,000 of repair costs related to leased railcars.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Organization	Organization Martin Marietta Materials, Inc. (the Company or Martin Marietta) is a natural resource-based building materials company. The Company supplies aggregates (crushed stone, sand and gravel) through its network of more than 300 quarries, mines and distribution yards to its customers in 30 states, Canada, the Bahamas and the Caribbean Islands. In the western United States, Martin Marietta also provides cement and downstream products, namely, ready mixed concrete, asphalt and paving services, in vertically-integrated structured markets where the Company has a leading aggregates position. The Company’s heavy-side building materials are used in infrastructure, nonresidential and residential construction projects. Aggregates are also used in agricultural, utility and environmental applications and as railroad ballast. The aggregates, cement, ready mixed concrete and asphalt and paving product lines are reported collectively as the “Building Materials” business. 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, Pennsylvania, South Carolina, Virginia, Washington and West Virginia Alabama, Florida, Georgia, Tennessee, Arkansas, Colorado, southern Kansas, Louisiana, western Nebraska, Nevada, Oklahoma, Texas, Utah and Wyoming Product Lines Aggregates Aggregates Aggregates, Cement, Ready Mixed Concrete, Asphalt and Paving The Company has a Magnesia Specialties business with manufacturing facilities in Manistee, Michigan, and Woodville, Ohio. The Magnesia Specialties business produces magnesia-based chemicals products used in industrial, agricultural and environmental applications, and dolomitic lime sold primarily to customers in the steel and mining industries.
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP) 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 required adoption of two new accounting pronouncements 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, 2017. 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 three- and nine-months ended September 30, 2018 are not indicative of the results expected for other interim periods or the full year. The consolidated balance sheet at December 31, 2017 has been derived from the audited consolidated financial statements at that date but does not include all of the information and notes required by U.S. GAAP 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, 2017.
New Accounting Pronouncements	New Accounting Pronouncements Revenue from Contracts with Customers Effective January 1, 2018, the Company adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments Effective January 1, 2018, the Company adopted ASU 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments
Pending Accounting Pronouncement	Pending Accounting Pronouncement Lease Standard In February 2016, the Financial Accounting Standards Board (FASB) issued a new accounting standard, Accounting Standards Codification 842 – Leases , The new standard provides a number of practical expedients for transition and policy elections for ongoing accounting. The Company expects to elect the “package of practical expedients”, which permits the Company to not reassess its prior conclusions about lease identification, lease classification and initial direct costs. The Company plans to elect the practical expedients pertaining to the use of hindsight and to land easements. The standard provides policy election options for recognition exemption for short-term leases and separation of lease and non-lease components. The Company will elect the short-term lease recognition exemption and expects to elect not to separate lease and non-lease components for all underlying asset classes with the exceptions of railcars and fleet leases. Although the Company has not determined the full impact of ASC 842, the Company expects the adoption of ASC 842 to have a material impact on its financial statements, specifically right-to-use assets and lease liabilities on the balance sheet and note disclosures pertaining to leasing activities.
Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss	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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Net earnings attributable to Martin Marietta Materials, Inc. $ 180,221 $ 151,546 $ 375,621 $ 336,159 Other comprehensive earnings, net of tax 4,392 2,978 7,613 7,759 Comprehensive earnings attributable to Martin Marietta Materials, Inc. $ 184,613 $ 154,524 $ 383,234 $ 343,918 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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Net earnings (loss) attributable to noncontrolling interests $ 132 $ (7 ) $ 275 $ (72 ) Other comprehensive earnings, net of tax — 8 1 10 Comprehensive earnings (loss) attributable to noncontrolling interests $ 132 $ 1 $ 276 $ (62 ) 1. Significant Accounting Policies (continued) Consolidated Comprehensive Earnings/Loss and Accumulated Other Comprehensive Loss (continued) Changes in accumulated other comprehensive earnings, 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 September 30, 2018 Balance at beginning of period $ (124,798 ) $ (1,085 ) $ — $ (125,883 ) Other comprehensive earnings before reclassifications, net of tax — 365 — 365 Amounts reclassified from accumulated other comprehensive loss, net of tax 4,027 — — 4,027 Other comprehensive earnings, net of tax 4,027 365 — 4,392 Balance at end of period $ (120,771 ) $ (720 ) $ — $ (121,491 ) Three-Months Ended September 30, 2017 Balance at beginning of period $ (124,553 ) $ (636 ) $ (717 ) $ (125,906 ) Other comprehensive earnings before reclassifications, net of tax — 838 — 838 Amounts reclassified from accumulated other comprehensive loss, net of tax 1,918 — 222 2,140 Other comprehensive earnings, net of tax 1,918 838 222 2,978 Balance at end of period $ (122,635 ) $ 202 $ (495 ) $ (122,928 ) 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 Nine-Months Ended September 30, 2018 Balance at beginning of period $ (128,802 ) $ (22 ) $ (280 ) $ (129,104 ) Other comprehensive loss before reclassifications, net of tax — (698 ) — (698 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 8,031 — 280 8,311 Other comprehensive earnings (loss), net of tax 8,031 (698 ) 280 7,613 Balance at end of period $ (120,771 ) $ (720 ) $ — $ (121,491 ) Nine-Months Ended September 30, 2017 Balance at beginning of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Other comprehensive earnings before reclassifications, net of tax — 1,364 — 1,364 Amounts reclassified from accumulated other comprehensive loss, net of tax 5,738 — 657 6,395 Other comprehensive earnings, net of tax 5,738 1,364 657 7,759 Balance at end of period $ (122,635 ) $ 202 $ (495 ) $ (122,928 ) 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 September 30, 2018 Balance at beginning of period $ 78,619 $ — $ 78,619 Tax effect of other comprehensive earnings (1,326 ) — (1,326 ) Balance at end of period $ 77,293 $ — $ 77,293 Three-Months Ended September 30, 2017 Balance at beginning of period $ 79,675 $ 464 $ 80,139 Tax effect of other comprehensive earnings (1,193 ) (147 ) (1,340 ) Balance at end of period $ 78,482 $ 317 $ 78,799 Nine-Months Ended September 30, 2018 Balance at beginning of period $ 79,938 $ 178 $ 80,116 Tax effect of other comprehensive earnings (2,645 ) (178 ) (2,823 ) Balance at end of period $ 77,293 $ — $ 77,293 Nine-Months Ended September 30, 2017 Balance at beginning of period $ 82,044 $ 749 $ 82,793 Tax effect of other comprehensive earnings (3,562 ) (432 ) (3,994 ) Balance at end of period $ 78,482 $ 317 $ 78,799 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 Nine-Months Ended Affected line items in the consolidated September 30, September 30, statements of earnings and 2018 2017 2018 2017 comprehensive earnings (Dollars in Thousands) Pension and postretirement benefit plans Settlement expense $ 2,692 $ — $ 2,692 $ — Amortization of: Prior service credit (492 ) (402 ) (1,479 ) (1,070 ) Actuarial loss 3,153 3,513 9,463 10,370 5,353 3,111 10,676 9,300 Other nonoperating income, net Tax benefit (1,326 ) (1,193 ) (2,645 ) (3,562 ) Income tax expense $ 4,027 $ 1,918 $ 8,031 $ 5,738 Unamortized value of terminated forward starting interest rate swap Additional interest expense $ — $ 369 $ 458 $ 1,089 Interest expense Tax benefit — (147 ) (178 ) (432 ) Income tax expense $ — $ 222 $ 280 $ 657
Earnings per Common Share	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 nine-months ended September 30, 2018 and 2017, the diluted per-share computations reflect 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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (In Thousands) Net earnings attributable to Martin Marietta Materials, Inc. $ 180,221 $ 151,546 $ 375,621 $ 336,159 Less: Distributed and undistributed earnings attributable to unvested awards 271 399 672 1,000 Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc. $ 179,950 $ 151,147 $ 374,949 $ 335,159 Basic weighted-average common shares outstanding 62,932 62,896 62,970 62,940 Effect of dilutive employee and director awards 235 262 254 278 Diluted weighted-average common shares outstanding 63,167 63,158 63,224 63,218

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Significant Accounting Policies [Line Items]
Changes in Accumulated Other Comprehensive Earnings Net of Tax	Changes in accumulated other comprehensive earnings, 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 September 30, 2018 Balance at beginning of period $ (124,798 ) $ (1,085 ) $ — $ (125,883 ) Other comprehensive earnings before reclassifications, net of tax — 365 — 365 Amounts reclassified from accumulated other comprehensive loss, net of tax 4,027 — — 4,027 Other comprehensive earnings, net of tax 4,027 365 — 4,392 Balance at end of period $ (120,771 ) $ (720 ) $ — $ (121,491 ) Three-Months Ended September 30, 2017 Balance at beginning of period $ (124,553 ) $ (636 ) $ (717 ) $ (125,906 ) Other comprehensive earnings before reclassifications, net of tax — 838 — 838 Amounts reclassified from accumulated other comprehensive loss, net of tax 1,918 — 222 2,140 Other comprehensive earnings, net of tax 1,918 838 222 2,978 Balance at end of period $ (122,635 ) $ 202 $ (495 ) $ (122,928 ) 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 Nine-Months Ended September 30, 2018 Balance at beginning of period $ (128,802 ) $ (22 ) $ (280 ) $ (129,104 ) Other comprehensive loss before reclassifications, net of tax — (698 ) — (698 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 8,031 — 280 8,311 Other comprehensive earnings (loss), net of tax 8,031 (698 ) 280 7,613 Balance at end of period $ (120,771 ) $ (720 ) $ — $ (121,491 ) Nine-Months Ended September 30, 2017 Balance at beginning of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Other comprehensive earnings before reclassifications, net of tax — 1,364 — 1,364 Amounts reclassified from accumulated other comprehensive loss, net of tax 5,738 — 657 6,395 Other comprehensive earnings, net of tax 5,738 1,364 657 7,759 Balance at end of period $ (122,635 ) $ 202 $ (495 ) $ (122,928 )
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 September 30, 2018 Balance at beginning of period $ 78,619 $ — $ 78,619 Tax effect of other comprehensive earnings (1,326 ) — (1,326 ) Balance at end of period $ 77,293 $ — $ 77,293 Three-Months Ended September 30, 2017 Balance at beginning of period $ 79,675 $ 464 $ 80,139 Tax effect of other comprehensive earnings (1,193 ) (147 ) (1,340 ) Balance at end of period $ 78,482 $ 317 $ 78,799 Nine-Months Ended September 30, 2018 Balance at beginning of period $ 79,938 $ 178 $ 80,116 Tax effect of other comprehensive earnings (2,645 ) (178 ) (2,823 ) Balance at end of period $ 77,293 $ — $ 77,293 Nine-Months Ended September 30, 2017 Balance at beginning of period $ 82,044 $ 749 $ 82,793 Tax effect of other comprehensive earnings (3,562 ) (432 ) (3,994 ) Balance at end of period $ 78,482 $ 317 $ 78,799
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 Nine-Months Ended Affected line items in the consolidated September 30, September 30, statements of earnings and 2018 2017 2018 2017 comprehensive earnings (Dollars in Thousands) Pension and postretirement benefit plans Settlement expense $ 2,692 $ — $ 2,692 $ — Amortization of: Prior service credit (492 ) (402 ) (1,479 ) (1,070 ) Actuarial loss 3,153 3,513 9,463 10,370 5,353 3,111 10,676 9,300 Other nonoperating income, net Tax benefit (1,326 ) (1,193 ) (2,645 ) (3,562 ) Income tax expense $ 4,027 $ 1,918 $ 8,031 $ 5,738 Unamortized value of terminated forward starting interest rate swap Additional interest expense $ — $ 369 $ 458 $ 1,089 Interest expense Tax benefit — (147 ) (178 ) (432 ) Income tax expense $ — $ 222 $ 280 $ 657
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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (In Thousands) Net earnings attributable to Martin Marietta Materials, Inc. $ 180,221 $ 151,546 $ 375,621 $ 336,159 Less: Distributed and undistributed earnings attributable to unvested awards 271 399 672 1,000 Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc. $ 179,950 $ 151,147 $ 374,949 $ 335,159 Basic weighted-average common shares outstanding 62,932 62,896 62,970 62,940 Effect of dilutive employee and director awards 235 262 254 278 Diluted weighted-average common shares outstanding 63,167 63,158 63,224 63,218
Parent
Significant Accounting Policies [Line Items]
Comprehensive Earnings	Comprehensive earnings attributable to Martin Marietta is as follows: Three-Months Ended Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Net earnings attributable to Martin Marietta Materials, Inc. $ 180,221 $ 151,546 $ 375,621 $ 336,159 Other comprehensive earnings, net of tax 4,392 2,978 7,613 7,759 Comprehensive earnings attributable to Martin Marietta Materials, Inc. $ 184,613 $ 154,524 $ 383,234 $ 343,918
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 Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Net earnings (loss) attributable to noncontrolling interests $ 132 $ (7 ) $ 275 $ (72 ) Other comprehensive earnings, net of tax — 8 1 10 Comprehensive earnings (loss) attributable to noncontrolling interests $ 132 $ 1 $ 276 $ (62 )

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Schedule of Company's Total Revenues by Category for each Reportable Segment	The following table presents the Company’s total revenues by category for each reportable segment: Three-Months Ended September 30, 2018 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 348,429 $ 28,576 $ 377,005 Southeast Group 121,661 3,886 125,547 West Group 603,763 39,802 643,565 Total Building Materials Business 1,073,853 72,264 1,146,117 Magnesia Specialties 68,365 5,158 73,523 Total $ 1,142,218 $ 77,422 $ 1,219,640 Three-Months Ended September 30, 2017 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 287,085 $ 21,387 $ 308,472 Southeast Group 91,427 3,416 94,843 West Group 584,086 36,426 620,512 Total Building Materials Business 962,598 61,229 1,023,827 Magnesia Specialties 59,889 4,016 63,905 Total $ 1,022,487 $ 65,245 $ 1,087,732 2. Revenue Recognition (continued) Nine-Months Ended September 30, 2018 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 841,897 $ 64,480 $ 906,377 Southeast Group 308,306 10,443 318,749 West Group 1,672,707 110,467 1,783,174 Total Building Materials Business 2,822,910 185,390 3,008,300 Magnesia Specialties 201,390 14,357 215,747 Total $ 3,024,300 $ 199,747 $ 3,224,047 Nine-Months Ended September 30, 2017 (Dollars in Thousands) Products and Services Freight Total Mid-America Group $ 734,406 $ 53,984 $ 788,390 Southeast Group 266,690 10,784 277,474 West Group 1,620,632 106,110 1,726,742 Total Building Materials Business 2,621,728 170,878 2,792,606 Magnesia Specialties 189,918 12,592 202,510 Total $ 2,811,646 $ 183,470 $ 2,995,116
Summary of Information About the Company's Contract Balances	The following table presents information about the Company’s contract balances: (Dollars in Thousands) September 30, 2018 December 31, 2017 September 30, 2017 Costs in excess of billings $ 5,581 $ 1,310 $ 8,727 Billings in excess of costs $ 9,111 $ 7,204 $ 5,981

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Summary of the Estimated Fair Values of the Assets Acquired and the Liabilities Assumed	The following is a summary of the estimated fair values of the assets acquired and the liabilities assumed (dollars in thousands). Assets: Cash $ 1,159 Receivables 25,479 Inventory 46,156 Other current assets 1,029 Property, plant and equipment 1,522,386 Intangible assets, other than goodwill 19,125 Goodwill 239,360 Total assets 1,854,694 Liabilities: Accounts payable and accrued expenses 17,893 Deferred income tax liabilities, net 210,443 Noncontrolling interest 9,001 Total liabilities 237,337 Total consideration $ 1,617,357
Business Acquisition, Pro Forma Information	The pro forma financial statements do not purport to project the future financial position or operating results of the combined company. The pro forma financial information as presented below is for informational purposes only and is not indicative of the results of operations that would have been achieved if the acquisition had taken place at the beginning of fiscal year 2017. Three-Months Ended Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands, except per share data) Total revenues $ 1,219,640 $ 1,148,787 $ 3,279,455 $ 3,154,563 Net earnings attributable to Martin Marietta $ 185,051 $ 151,986 $ 399,113 $ 300,458 Diluted EPS $ 2.93 $ 2.41 $ 6.31 $ 4.75

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Changes in Goodwill	Mid-America Southeast West Group Group Group Total (Dollars in Thousands) Balance at January 1, 2018 $ 281,403 $ 50,346 $ 1,828,541 $ 2,160,290 Acquisitions 147,333 92,738 — 240,071 Divestitures — (927 ) — (927 ) Balance at September 30, 2018 $ 428,736 $ 142,157 $ 1,828,541 $ 2,399,434
Intangible Assets Subject to Amortization	Intangible assets subject to amortization consist of the following: Gross Amount Accumulated Amortization Net Balance (Dollars in Thousands) September 30, 2018 Noncompetition agreements $ 12,024 $ (11,105 ) $ 919 Customer relationships 56,530 (18,325 ) 38,205 Operating permits 458,952 (31,375 ) 427,577 Use rights and other 19,564 (10,789 ) 8,775 Trade names 12,800 (9,387 ) 3,413 Total $ 559,870 $ (80,981 ) $ 478,889
Intangible Assets Deemed to Indefinite Life and Not Being Amortized	Intangible assets deemed to have an indefinite life and not being amortized consist of the following: Building Materials Business Magnesia Specialties Total (Dollars in Thousands) September 30, 2018 Operating permits $ 6,600 $ — $ 6,600 Use rights 20,642 — 20,642 Trade names 280 2,565 2,845 Total $ 27,522 $ 2,565 $ 30,087
Schedule of Acquired Intangibles	Intangibles acquired during the year are as follows: (Dollars in Thousands) Amount Weighted-average amortization period Subject to amortization: Customer relationships $ 20,620 12 years Not subject to amortization: Water rights 1,100 N/A Total $ 21,720
Estimated Amortization Expense of Intangible Assets	The estimated amortization expense for intangible assets for the last three months of 2018 and for each of the next four years and thereafter is as follows: (Dollars in Thousands) October - December 2018 $ 3,398 2019 13,429 2020 13,393 2021 12,703 2022 11,232 Thereafter 424,734 Total $ 478,889

Inventories, Net (Tables)

Inventories, Net (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Schedule of Inventories Net	September 30, December 31, September 30, 2018 2017 2017 (Dollars in Thousands) Finished products $ 610,663 $ 552,999 $ 526,404 Products in process and raw materials 61,891 62,761 62,449 Supplies and expendable parts 139,409 128,792 126,918 811,963 744,552 715,771 Less: Allowances (160,668 ) (143,961 ) (139,342 ) Total $ 651,295 $ 600,591 $ 576,429

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-Term Debt	September 30, December 31, September 30, 2018 2017 2017 (Dollars in Thousands) 6.60% Senior Notes, due 2018 $ — $ 299,871 $ 299,774 7% Debentures, due 2025 124,249 124,180 124,157 6.25% Senior Notes, due 2037 228,079 228,033 228,018 4.25% Senior Notes, due 2024 396,251 395,814 395,673 4.250% Senior Notes, due 2047 591,499 591,688 — 3.500% Senior Notes, due 2027 494,643 494,352 — 3.450% Senior Notes, due 2027 296,861 296,628 296,551 Floating Rate Senior Notes, due 2019, interest rate of 2.84% and 2.13% at September 30, 2018 and December 31, 2017, respectively 299,074 298,102 — Floating Rate Notes, due 2020, interest rate of 2.96%, 2.10% and 1.96% at September 30, 2018, December 31, 2017 and September 30, 2017, respectively 298,773 298,227 298,046 Revolving Facility, due 2022, interest rate of 3.29% at September 30, 2018 100,000 — — Trade Receivable Facility, interest rate of 2.83% and 1.96% at September 30, 2018 and 2017, respectively 380,000 — 80,000 Other notes 269 308 321 Total debt 3,209,698 3,027,203 1,722,540 Less: Current maturities of long-term debt and short-term facilities (380,041 ) (299,909 ) (80,038 ) Long-term debt $ 2,829,657 $ 2,727,294 $ 1,642,502

Pension and Postretirement Be_2

Pension and Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2018
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 September 30, Pension Postretirement Benefits 2018 2017 2018 2017 (Dollars in Thousands) Service cost $ 7,911 $ 7,457 $ 19 $ 20 Interest cost 8,307 9,729 130 182 Expected return on assets (11,516 ) (10,691 ) — — Amortization of: Prior service cost (credit) 27 34 (519 ) (436 ) Actuarial loss (gain) 3,206 3,604 (53 ) (91 ) Settlement charge 2,692 — — — Net periodic benefit cost (credit) $ 10,627 $ 10,133 $ (423 ) $ (325 ) Nine-Months Ended September 30, Pension Postretirement Benefits 2018 2017 2018 2017 (Dollars in Thousands) Service cost $ 23,732 $ 20,060 $ 58 $ 60 Interest cost 24,921 27,074 389 547 Expected return on assets (34,549 ) (29,818 ) — — Amortization of: Prior service cost (credit) 77 237 (1,556 ) (1,307 ) Actuarial loss (gain) 9,621 10,643 (158 ) (273 ) Settlement charge 2,692 — — — Net periodic benefit cost (credit) $ 26,494 $ 28,196 $ (1,267 ) $ (973 )

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Financial Data for Continuing Operation for Company's Reportable Business Segments	The following table displays selected financial data for the Company’s reportable business segments. The acquired Bluegrass operations are located in the Mid-America Group and Southeast Group. Total revenues, as well as the consolidated statements of earnings and comprehensive earnings, exclude intersegment revenues which represent sales from one segment to another segment, which are eliminated. Prior-year information has been reclassified to conform to current year revenue presentation. Three-Months Ended Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Total revenues Mid-America Group $ 377,005 $ 308,472 $ 906,377 $ 788,390 Southeast Group 125,547 94,843 318,749 277,474 West Group 643,565 620,512 1,783,174 1,726,742 Total Building Materials Business 1,146,117 1,023,827 3,008,300 2,792,606 Magnesia Specialties 73,523 63,905 215,747 202,510 Total $ 1,219,640 $ 1,087,732 $ 3,224,047 $ 2,995,116 Products and services revenues: Mid-America Group $ 348,429 $ 287,085 $ 841,897 $ 734,406 Southeast Group 121,661 91,427 308,306 266,690 West Group 603,763 584,086 1,672,707 1,620,632 Total Building Materials Business 1,073,853 962,598 2,822,910 2,621,728 Magnesia Specialties 68,365 59,889 201,390 189,918 Total $ 1,142,218 $ 1,022,487 $ 3,024,300 $ 2,811,646 Earnings (Loss) from operations Mid-America Group $ 120,344 $ 106,235 $ 235,221 $ 204,939 Southeast Group 26,372 17,882 60,464 42,331 West Group 92,090 96,522 249,885 270,246 Total Building Materials Business 238,806 220,639 545,570 517,516 Magnesia Specialties 23,301 17,590 65,867 58,589 Corporate (21,445 ) (11,265 ) (67,741 ) (59,138 ) Total $ 240,662 $ 226,964 $ 543,696 $ 516,967 September 30, 2018 December 31, 2017 September 30, 2017 Assets employed: (Dollars in thousands) Mid-America Group $ 2,802,054 $ 1,532,867 $ 1,538,594 Southeast Group 1,300,090 616,344 604,144 West Group 5,032,662 5,014,231 5,032,103 Total Building Materials Business 9,134,806 7,163,442 7,174,841 Magnesia Specialties 141,998 152,257 148,581 Corporate 311,367 1,676,812 243,363 Total $ 9,588,171 $ 8,992,511 $ 7,566,785

Revenues and Gross Profit (Tabl

Revenues and Gross Profit (Tables)	9 Months Ended
	Sep. 30, 2018
Revenues And Gross Profit [Abstract]
Total Revenues and Gross Profit by Product Line	The following table, which is reconciled to consolidated amounts, provides total revenues and gross profit by product line. Three-Months Ended Nine-Months Ended September 30, September 30, 2018 2017 2018 2017 (Dollars in Thousands) Total revenues: Building Materials Business: Products and services: Aggregates $ 687,800 $ 590,312 $ 1,778,124 $ 1,619,282 Cement 98,223 88,470 300,554 280,961 Ready mixed concrete 254,686 240,222 750,424 704,471 Asphalt and paving services 99,983 110,973 199,489 215,652 Less: interproduct revenues (66,839 ) (67,379 ) (205,681 ) (198,638 ) Products and services 1,073,853 962,598 2,822,910 2,621,728 Freight 72,264 61,229 185,390 170,878 Total Building Materials Business 1,146,117 1,023,827 3,008,300 2,792,606 Magnesia Specialties: Products and services 68,365 59,889 201,390 189,918 Freight 5,158 4,016 14,357 12,592 Total Magnesia Specialties 73,523 63,905 215,747 202,510 Total $ 1,219,640 $ 1,087,732 $ 3,224,047 $ 2,995,116 Gross profit (loss) Building Materials Business: Products and services: Aggregates $ 209,082 $ 187,065 $ 460,624 $ 439,032 Cement 32,543 27,459 97,582 87,608 Ready mixed concrete 20,632 23,913 66,226 70,542 Asphalt and paving services 25,606 28,873 36,479 44,446 Products and services 287,863 267,310 660,911 641,628 Freight (47 ) 1,012 432 2,040 Total Building Materials Business 287,816 268,322 661,343 643,668 Magnesia Specialties: Products and services 26,823 21,272 76,756 69,425 Freight (1,076 ) (1,362 ) (3,280 ) (3,576 ) Total Magnesia Specialties 25,747 19,910 73,476 65,849 Corporate (579 ) 3,446 4,474 3,321 Total $ 312,984 $ 291,678 $ 739,293 $ 712,838

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2018
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: Nine-Months Ended September 30, 2018 2017 (Dollars in Thousands) Other current and noncurrent assets $ (32,572 ) $ (29,342 ) Accrued salaries, benefits and payroll taxes 5,986 (6,234 ) Accrued insurance and other taxes 4,555 10,230 Accrued income taxes 6,220 16,393 Accrued pension, postretirement and postemployment benefits (131,963 ) (5,807 ) Other current and noncurrent liabilities 2,769 49,244 $ (145,005 ) $ 34,484
Schedule Of Other Significant Noncash Transactions	Noncash investing and financing activities are as follows: Nine-Months Ended September 30, 2018 2017 (Dollars in Thousands) Noncash investing and financing activities: Accrued liabilities for purchases of property, plant and equipment $ 24,930 $ 20,339 Acquisition of assets through capital lease $ 449 $ 196 Settlement of royalty obligation via asset sale $ — $ 900
Supplemental Disclosures of Cash Flow Information	Supplemental disclosures of cash flow information are as follows: Nine-Months Ended September 30, 2018 2017 (Dollars in Thousands) Cash paid for interest $ 84,522 $ 49,564 Cash paid for income taxes $ 7,253 $ 96,643

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018FacilityStateSegment
Significant Accounting Policies [Line Items]
Number of states with aggregates business sales by destination | State	30
Number of reportable segments | Segment	3
Minimum [Member]
Significant Accounting Policies [Line Items]
Number of quarries and yards | Facility	300

Significant Accounting Polici_5

Significant Accounting Policies - Comprehensive Earnings Attributable to Martin Marietta Materials Incorporated (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net earnings attributable to Martin Marietta Materials, Inc.	$ 180,221	$ 151,546	$ 375,621	$ 336,159
Other comprehensive earnings, net of tax	4,392	2,978	7,613	7,759
Earnings attributable to Martin Marietta Materials, Inc.	$ 184,613	$ 154,524	$ 383,234	$ 343,918

Significant Accounting Polici_6

Significant Accounting Policies - Comprehensive Earnings Attributable to Noncontrolling Interests (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net earnings (loss) attributable to noncontrolling interests	$ 132	$ (7)	$ 275	$ (72)
Other comprehensive earnings, net of tax		8	1	10
Comprehensive earnings (loss) attributable to noncontrolling interests	$ 132	$ 1	$ 276	$ (62)

Significant Accounting Polici_7

Significant Accounting Policies - Changes in Accumulated Other Comprehensive Earnings Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 4,682,477	$ 4,142,590
Other comprehensive earnings before reclassifications, net of tax	$ 365	$ 838	(698)	1,364
Amounts reclassified from accumulated other comprehensive loss, net of tax	4,027	2,140	8,311	6,395
Other comprehensive earnings, net of tax	4,392	2,978	7,613	7,759
Ending Balance	4,942,328	4,333,982	4,942,328	4,333,982
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(124,798)	(124,553)	(128,802)	(128,373)
Amounts reclassified from accumulated other comprehensive loss, net of tax	4,027	1,918	8,031	5,738
Other comprehensive earnings, net of tax	4,027	1,918	8,031	5,738
Ending Balance	(120,771)	(122,635)	(120,771)	(122,635)
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(1,085)	(636)	(22)	(1,162)
Other comprehensive earnings before reclassifications, net of tax	365	838	(698)	1,364
Other comprehensive earnings, net of tax	365	838	(698)	1,364
Ending Balance	(720)	202	(720)	202
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(717)	(280)	(1,152)
Amounts reclassified from accumulated other comprehensive loss, net of tax		222	280	657
Other comprehensive earnings, net of tax		222	280	657
Ending Balance		(495)		(495)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(125,883)	(125,906)	(129,104)	(130,687)
Ending Balance	$ (121,491)	$ (122,928)	$ (121,491)	$ (122,928)

Significant Accounting Polici_8

Significant Accounting Policies - Noncurrent Deferred Tax Assets Recorded in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Equity [Abstract]
Balance at beginning of period, Pension and Postretirement Benefit Plans	$ 78,619	$ 79,675	$ 79,938	$ 82,044
Tax effect of other comprehensive earnings, Pension and Postretirement Benefit Plans	(1,326)	(1,193)	(2,645)	(3,562)
Balance at end of period, Pension and Postretirement Benefit Plans	77,293	78,482	77,293	78,482
Balance at beginning of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap		464	178	749
Tax effect of other comprehensive earnings, Unamortized Value of Terminated Forward Starting Interest Rate Swap		(147)	(178)	(432)
Balance at end of period, Unamortized Value of Terminated Forward Starting Interest Rate Swap		317		317
Balance at beginning of period, Net Noncurrent Deferred Tax Assets	78,619	80,139	80,116	82,793
Tax effect of other comprehensive earnings, Net Noncurrent Deferred Tax Assets	(1,326)	(1,340)	(2,823)	(3,994)
Balance at end of period, Net Noncurrent Deferred Tax Assets	$ 77,293	$ 78,799	$ 77,293	$ 78,799

Significant Accounting Polici_9

Significant Accounting Policies - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Additional interest expense	$ 35,468	$ 23,141	$ 103,526	$ 68,037
Tax benefit	29,089	52,763	84,147	119,277
Earnings from Continuing Operations	4,027	2,140	8,311	6,395
Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	4,027	1,918	8,031	5,738
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations		222	280	657
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Settlement expense	2,692		2,692
Prior service credit	(492)	(402)	(1,479)	(1,070)
Actuarial loss	3,153	3,513	9,463	10,370
Tax benefit	(1,326)	(1,193)	(2,645)	(3,562)
Earnings from Continuing Operations	4,027	1,918	8,031	5,738
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefit Plans | Other Nonoperating Income, Net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications out of accumulated other comprehensive loss before taxes	$ 5,353	3,111	10,676	9,300
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		369	458	1,089
Tax benefit		(147)	(178)	(432)
Earnings from Continuing Operations		$ 222	$ 280	$ 657

Significant Accounting Polic_10

Significant Accounting Policies - Basic and Diluted Earnings Per Common Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net earnings attributable to Martin Marietta Materials, Inc.	$ 180,221	$ 151,546	$ 375,621	$ 336,159
Less: Distributed and undistributed earnings attributable to unvested awards	271	399	672	1,000
Basic and diluted net earnings available to common shareholders attributable to Martin Marietta Materials, Inc.	$ 179,950	$ 151,147	$ 374,949	$ 335,159
Basic weighted-average common shares outstanding	62,932	62,896	62,970	62,940
Effect of dilutive employee and director awards	235	262	254	278
Diluted weighted-average common shares outstanding	63,167	63,158	63,224	63,218

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenue Recognition [Line Items]
Performance obligations, description of timing			Performance obligations within paving service agreements are satisfied over time, primarily ranging from one day to 20 months. For product revenues and freight revenues, customer payment terms are generally 30 days from invoice date. Customer payments for the paving operations are based on a contractual billing schedule and are due 30 days from invoice date.
Product and freight revenues customer payment terms			30 days
Customer payments term based on contractual billing			30 days
Future revenues from unsatisfied performance obligations	$ 111,721,000	$ 107,953,000	$ 111,721,000	$ 107,953,000
Service revenues	1,219,640,000	1,087,732,000	3,224,047,000	2,995,116,000
Revenue recognized from contract liabilities	6,203,000	4,439,000	6,816,000	8,231,000
Retainage on contracts	8,733,000	7,680,000	8,733,000	7,680,000	$ 9,029,000
Service | COLORADO
Revenue Recognition [Line Items]
Service revenues	$ 82,232,000,000	$ 94,503,000,000	$ 162,944,000,000	$ 179,553,000,000
Minimum [Member]
Revenue Recognition [Line Items]
Performance obligations, customer satisfaction period	1 month	1 month	1 month	1 month
Construction contracts warranty provisions period			9 months
Minimum [Member] | Service
Revenue Recognition [Line Items]
Performance obligations, period			1 day
Maximum [Member]
Revenue Recognition [Line Items]
Performance obligations, customer satisfaction period	27 months	21 months	27 months	21 months
Construction contracts warranty provisions period			1 year
Maximum [Member] | Service
Revenue Recognition [Line Items]
Performance obligations, period			20 months

Revenue Recognition - Schedule

Revenue Recognition - Schedule of Company's Total Revenues by Category for each Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue Recognition [Line Items]
Total	$ 1,219,640	$ 1,087,732	$ 3,224,047	$ 2,995,116
Building Materials Business
Revenue Recognition [Line Items]
Total	1,146,117	1,023,827	3,008,300	2,792,606
Products and Services
Revenue Recognition [Line Items]
Total	1,142,218	1,022,487	3,024,300	2,811,646
Products and Services | Building Materials Business
Revenue Recognition [Line Items]
Total	1,073,853	962,598	2,822,910	2,621,728
Freight
Revenue Recognition [Line Items]
Total	77,422	65,245	199,747	183,470
Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	72,264	61,229	185,390	170,878
Operating Segments | Building Materials Business Mid-America Group
Revenue Recognition [Line Items]
Total	377,005	308,472	906,377	788,390
Operating Segments | Building Materials Business Southeast Group
Revenue Recognition [Line Items]
Total	125,547	94,843	318,749	277,474
Operating Segments | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	643,565	620,512	1,783,174	1,726,742
Operating Segments | Building Materials Business
Revenue Recognition [Line Items]
Total	1,146,117	1,023,827	3,008,300	2,792,606
Operating Segments | Magnesia Specialties
Revenue Recognition [Line Items]
Total	73,523	63,905	215,747	202,510
Operating Segments | Products and Services | Building Materials Business Mid-America Group
Revenue Recognition [Line Items]
Total	348,429	287,085	841,897	734,406
Operating Segments | Products and Services | Building Materials Business Southeast Group
Revenue Recognition [Line Items]
Total	121,661	91,427	308,306	266,690
Operating Segments | Products and Services | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	603,763	584,086	1,672,707	1,620,632
Operating Segments | Products and Services | Magnesia Specialties
Revenue Recognition [Line Items]
Total	68,365	59,889	201,390	189,918
Operating Segments | Freight | Building Materials Business Mid-America Group
Revenue Recognition [Line Items]
Total	28,576	21,387	64,480	53,984
Operating Segments | Freight | Building Materials Business Southeast Group
Revenue Recognition [Line Items]
Total	3,886	3,416	10,443	10,784
Operating Segments | Freight | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	39,802	36,426	110,467	106,110
Operating Segments | Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	72,264	61,229	185,390	170,878
Operating Segments | Freight | Magnesia Specialties
Revenue Recognition [Line Items]
Total	$ 5,158	$ 4,016	$ 14,357	$ 12,592

Revenue Recognition - Summary o

Revenue Recognition - Summary of Information About the Company's Contract Balances (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Revenue From Contract With Customer [Abstract]
Costs in excess of billings	$ 5,581	$ 1,310	$ 8,727
Billings in excess of costs	$ 9,111	$ 7,204	$ 5,981

Business Combination - Addition

Business Combination - Additional Information (Details) - USD ($)	Apr. 27, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Combinations [Line Items]
Total revenues		$ 1,219,640,000	$ 1,087,732,000	$ 3,224,047,000	$ 2,995,116,000
Earnings from operations		240,662,000	226,964,000	543,696,000	516,967,000
Acquisition-related expenses		89,000	$ 1,314,000	12,925,000	3,319,000
Bluegrass Materials Company
Business Combinations [Line Items]
Date of acquisition	Apr. 27, 2018
Gain on sale of business					14,785,000
Purchase price	$ 1,617,357,000
Company acquired voting interest	100.00%
Total revenues		68,656,000		115,007,000
Earnings from operations		11,531,000		18,276,000
Acquisition-related expenses		$ 89,000		$ 27,710,000	27,710,000
Increase in cost of sales					$ 19,893,000
Bluegrass Materials Company | Forsyth Quarry
Business Combinations [Line Items]
Gain on sale of business	$ 14,785,000
Bluegrass Materials Company | Beaver Creek
Business Combinations [Line Items]
Gain on sale of business	$ 0

Business Combination - Summary

Business Combination - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Apr. 27, 2018	Dec. 31, 2017	Sep. 30, 2017
Assets:
Goodwill	$ 2,399,434		$ 2,160,290	$ 2,160,060
Bluegrass Materials Company
Assets:
Cash		$ 1,159
Receivables		25,479
Inventory		46,156
Other current assets		1,029
Property, plant and equipment		1,522,386
Intangible assets, other than goodwill		19,125
Goodwill		239,360
Total assets		1,854,694
Liabilities:
Accounts payable and accrued expenses		17,893
Deferred income tax liabilities, net		210,443
Noncontrolling interest		9,001
Total liabilities		237,337
Total consideration		$ 1,617,357

Business Combination - Business

Business Combination - Business Acquisition, Pro Forma Information (Details) - Bluegrass Materials Company - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Total revenues	$ 1,219,640	$ 1,148,787	$ 3,279,455	$ 3,154,563
Net earnings attributable to Martin Marietta	$ 185,051	$ 151,986	$ 399,113	$ 300,458
Diluted EPS	$ 2.93	$ 2.41	$ 6.31	$ 4.75

Goodwill and Other Intangibles

Goodwill and Other Intangibles - Changes in Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill [Line Items]
Balance at January 1, 2018	$ 2,160,290
Acquisitions	240,071
Divestitures	(927)
Balance at September 30, 2018	2,399,434
Mid-America Group
Goodwill [Line Items]
Balance at January 1, 2018	281,403
Acquisitions	147,333
Balance at September 30, 2018	428,736
Southeast Group
Goodwill [Line Items]
Balance at January 1, 2018	50,346
Acquisitions	92,738
Divestitures	(927)
Balance at September 30, 2018	142,157
West Group
Goodwill [Line Items]
Balance at January 1, 2018	1,828,541
Balance at September 30, 2018	$ 1,828,541

Goodwill and Other Intangible_3

Goodwill and Other Intangibles - Intangible Assets Subject to Amortization (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Finite Lived Intangible Assets [Line Items]
Gross Amount	$ 559,870
Accumulated Amortization	(80,981)
Net Balance	478,889
Noncompetition agreements
Finite Lived Intangible Assets [Line Items]
Gross Amount	12,024
Accumulated Amortization	(11,105)
Net Balance	919
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross Amount	56,530
Accumulated Amortization	(18,325)
Net Balance	38,205
Operating Permits
Finite Lived Intangible Assets [Line Items]
Gross Amount	458,952
Accumulated Amortization	(31,375)
Net Balance	427,577
Use Rights And Other
Finite Lived Intangible Assets [Line Items]
Gross Amount	19,564
Accumulated Amortization	(10,789)
Net Balance	8,775
Trade names
Finite Lived Intangible Assets [Line Items]
Gross Amount	12,800
Accumulated Amortization	(9,387)
Net Balance	$ 3,413

Goodwill and Other Intangible_4

Goodwill and Other Intangibles - Intangible Assets Deemed to Indefinite Life and Not Being Amortized (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	$ 30,087
Building Materials Business
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	27,522
Magnesia Specialties
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	2,565
Operating Permits
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	6,600
Operating Permits | Building Materials Business
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	6,600
Use Rights Not Subject To Amortization
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	20,642
Use Rights Not Subject To Amortization | Building Materials Business
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	20,642
Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	2,845
Trade names | Building Materials Business
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	280
Trade names | Magnesia Specialties
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	$ 2,565

Goodwill and Other Intangible_5

Goodwill and Other Intangibles - Schedule of Acquired Intangibles (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Acquired Finite Lived Intangible Assets [Line Items]
Acquired intangibles subject to amortization and not subject to amortization	$ 21,720
Water Rights
Acquired Finite Lived Intangible Assets [Line Items]
Acquired intangibles not subject to amortization	1,100
Customer Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Acquired intangibles subject to amortization	$ 20,620
Acquired Finite-lived Intangible Assets, Useful Life	12 years

Goodwill and Other Intangible -

Goodwill and Other Intangible - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 10,549,000	$ 10,710,000

Goodwill and Other Intangible_6

Goodwill and Other Intangibles - Estimated Amortization Expense of Intangible Assets (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
October - December 2018	$ 3,398
2,019	13,429
2,020	13,393
2,021	12,703
2,022	11,232
Thereafter	424,734
Net Balance	$ 478,889

Inventories, Net - Schedule of

Inventories, Net - Schedule of Inventories Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Inventory Disclosure [Abstract]
Finished products	$ 610,663	$ 552,999	$ 526,404
Products in process and raw materials	61,891	62,761	62,449
Supplies and expendable parts	139,409	128,792	126,918
Inventories, Gross	811,963	744,552	715,771
Less: Allowances	(160,668)	(143,961)	(139,342)
Total	$ 651,295	$ 600,591	$ 576,429

Long-Term Debt (Detail)

Long-Term Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Debt Instrument [Line Items]
Total debt	$ 3,209,698	$ 3,027,203	$ 1,722,540
Less: Current maturities of long-term debt and short-term facilities	(380,041)	(299,909)	(80,038)
Long-term debt	2,829,657	2,727,294	1,642,502
Revolving Facility, Due 2022
Debt Instrument [Line Items]
Total debt	100,000
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Total debt		299,871	299,774
7% Debentures, Due 2025
Debt Instrument [Line Items]
Total debt	124,249	124,180	124,157
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Total debt	228,079	228,033	228,018
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total debt	396,251	395,814	395,673
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Total debt	591,499	591,688
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total debt	494,643	494,352
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Total debt	298,773	298,227	298,046
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total debt	296,861	296,628	296,551
Floating Rate Notes, Due 2019
Debt Instrument [Line Items]
Total debt	299,074	298,102
Trade Receivable Facility
Debt Instrument [Line Items]
Total debt	380,000		80,000
Other Notes
Debt Instrument [Line Items]
Total debt	$ 269	$ 308	$ 321

Long-Term Debt (Parenthetical)

Long-Term Debt (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2018	Apr. 16, 2018	Dec. 31, 2017	Sep. 30, 2017
Revolving Facility, Due 2022
Debt Instrument [Line Items]
Maturity year	2,022
Credit Facility interest rate	3.29%
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Maturity year	2,018
Interest rate on notes	6.60%	6.60%
7% Debentures, Due 2025
Debt Instrument [Line Items]
Maturity year	2,025
Interest rate on notes	7.00%
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Maturity year	2,037
Interest rate on notes	6.25%
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Maturity year	2,024
Interest rate on notes	4.25%
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Maturity year	2,047
Interest rate on notes	4.25%
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Maturity year	2,027
Interest rate on notes	3.45%
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Maturity year	2,027
Interest rate on notes	3.50%
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Maturity year	2,020
Interest rate	2.96%		2.10%	1.96%
Floating Rate Notes, Due 2019
Debt Instrument [Line Items]
Maturity year	2,019
Interest rate	2.84%		2.13%
Trade Receivable Facility
Debt Instrument [Line Items]
Credit Facility interest rate	2.83%			1.96%

Long-Term Debt - Additional inf

Long-Term Debt - Additional information (Detail) - USD ($)	Apr. 16, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Apr. 17, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Maximum consolidated debt reduction for unrestricted cash and cash equivalents for debt covenant calculation			$ 200,000,000
Additional interest expense		$ 369,000	458,000	$ 1,089,000
Minimum [Member]
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			350.00%
Excluding Acquisition Bridge Debt | Maximum
Debt Instrument [Line Items]
Debt covenant			375.00%
Revolving Facility
Debt Instrument [Line Items]
Credit facility commitment			$ 700,000,000
Senior unsecured revolving facility, maturity period			5 years
Outstanding letters of credit		1,963,000	$ 2,301,000	1,963,000		$ 2,301,000
Trade Receivable Facility
Debt Instrument [Line Items]
Credit facility commitment					$ 400,000,000
Debt instrument maturity period			Sep. 25, 2019
Credit facility borrowing base		$ 402,754,000	$ 465,217,000	$ 402,754,000		$ 338,784,000
Trade Receivable Facility | London Interbank Offered Rate(LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate			0.725%
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Maturity date	Apr. 16, 2018
Repayments of credit facility	$ 300,000,000
Interest rate on notes	6.60%		6.60%

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Long-term debt, carrying values	$ 3,209,698	$ 3,027,203	$ 1,722,540
Long-term debt, fair values	$ 3,144,615	$ 3,144,902	$ 1,830,750

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Taxes [Line Items]
Effective income tax rate			18.30%	26.20%
Net income tax benefit			$ 15,454,000
Contribution made to qualified pension plans	$ 25,000,000
Federal statutory corporate income tax rate			21.00%		35.00%
Qualified Pension Plan [Member]
Income Taxes [Line Items]
Additional contribution made to qualified pension plans		$ 125,000,000
Contribution made to qualified pension plans		$ 150,000,000

Pension and Postretirement Be_3

Pension and Postretirement Benefits - Schedule of Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 7,911	$ 7,457	$ 23,732	$ 20,060
Interest cost	8,307	9,729	24,921	27,074
Expected return on assets	(11,516)	(10,691)	(34,549)	(29,818)
Prior service cost (credit)	27	34	77	237
Actuarial loss (gain)	3,206	3,604	9,621	10,643
Settlement charge	2,692		2,692
Net periodic benefit cost (credit)	10,627	10,133	26,494	28,196
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	19	20	58	60
Interest cost	130	182	389	547
Prior service cost (credit)	(519)	(436)	(1,556)	(1,307)
Actuarial loss (gain)	(53)	(91)	(158)	(273)
Net periodic benefit cost (credit)	$ (423)	$ (325)	$ (1,267)	$ (973)

Pension and Postretirement Be_4

Pension and Postretirement Benefits - Additional Information (Detail) - USD ($)	Jun. 30, 2018	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Contribution made to qualified pension plans	$ 25,000,000
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution made to qualified pension plans		$ 150,000,000
Estimated contribution to pension plans, remainder of financal year		0
Nonqualified Pension Plan [Member] | Underfunded Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated contribution to pension plans		$ 12,400,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Commitments and Contingencies [Line Items]
Guarantee of affiliate's obligations	$ 15,500,000
Woodville
Commitments and Contingencies [Line Items]
Collective bargaining agreement expiration month year	2022-06
Magnesia Specialties
Commitments and Contingencies [Line Items]
Percentage of employees represented in labor union	100.00%
Collective bargaining agreement expiration month year	2019-08
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%
Revolving Line Of Credit Expires In August 2015
Commitments and Contingencies [Line Items]
Line of credit maturity date	2020-03

Business Segments - Additional

Business Segments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018Segment
Segment Reporting [Abstract]
Reportable business segments	3

Business Segments - Financial D

Business Segments - Financial Data for Continuing Operations for Company's Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total Revenues	$ 1,219,640	$ 1,087,732	$ 3,224,047	$ 2,995,116
Earnings (Loss) from operations	240,662	226,964	543,696	516,967
Total assets employed	9,588,171	7,566,785	9,588,171	7,566,785	$ 8,992,511
Products and Services
Segment Reporting Information [Line Items]
Total Revenues	1,142,218	1,022,487	3,024,300	2,811,646
Building Materials Business
Segment Reporting Information [Line Items]
Total Revenues	1,146,117	1,023,827	3,008,300	2,792,606
Earnings (Loss) from operations	238,806	220,639	545,570	517,516
Total assets employed	9,134,806	7,174,841	9,134,806	7,174,841	7,163,442
Building Materials Business | Products and Services
Segment Reporting Information [Line Items]
Total Revenues	1,073,853	962,598	2,822,910	2,621,728
Operating Segments | Building Materials Business Mid-America Group
Segment Reporting Information [Line Items]
Total Revenues	377,005	308,472	906,377	788,390
Earnings (Loss) from operations	120,344	106,235	235,221	204,939
Total assets employed	2,802,054	1,538,594	2,802,054	1,538,594	1,532,867
Operating Segments | Building Materials Business Mid-America Group | Products and Services
Segment Reporting Information [Line Items]
Total Revenues	348,429	287,085	841,897	734,406
Operating Segments | Building Materials Business Southeast Group
Segment Reporting Information [Line Items]
Total Revenues	125,547	94,843	318,749	277,474
Earnings (Loss) from operations	26,372	17,882	60,464	42,331
Total assets employed	1,300,090	604,144	1,300,090	604,144	616,344
Operating Segments | Building Materials Business Southeast Group | Products and Services
Segment Reporting Information [Line Items]
Total Revenues	121,661	91,427	308,306	266,690
Operating Segments | Building Materials Business West Group
Segment Reporting Information [Line Items]
Total Revenues	643,565	620,512	1,783,174	1,726,742
Earnings (Loss) from operations	92,090	96,522	249,885	270,246
Total assets employed	5,032,662	5,032,103	5,032,662	5,032,103	5,014,231
Operating Segments | Building Materials Business West Group | Products and Services
Segment Reporting Information [Line Items]
Total Revenues	603,763	584,086	1,672,707	1,620,632
Operating Segments | Building Materials Business
Segment Reporting Information [Line Items]
Total Revenues	1,146,117	1,023,827	3,008,300	2,792,606
Operating Segments | Magnesia Specialties
Segment Reporting Information [Line Items]
Total Revenues	73,523	63,905	215,747	202,510
Earnings (Loss) from operations	23,301	17,590	65,867	58,589
Total assets employed	141,998	148,581	141,998	148,581	152,257
Operating Segments | Magnesia Specialties | Products and Services
Segment Reporting Information [Line Items]
Total Revenues	68,365	59,889	201,390	189,918
Corporate
Segment Reporting Information [Line Items]
Earnings (Loss) from operations	(21,445)	(11,265)	(67,741)	(59,138)
Total assets employed	$ 311,367	$ 243,363	$ 311,367	$ 243,363	$ 1,676,812

Revenues and Gross Profit - Tot

Revenues and Gross Profit - Total Revenues and Gross Profit by Product Line (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Product Information [Line Items]
Total Revenues	$ 1,219,640	$ 1,087,732	$ 3,224,047	$ 2,995,116
Gross profit (loss)	312,984	291,678	739,293	712,838
Interproduct Revenues
Product Information [Line Items]
Total Revenues	(66,839)	(67,379)	(205,681)	(198,638)
Corporate
Product Information [Line Items]
Gross profit (loss)	(579)	3,446	4,474	3,321
Building Materials Business
Product Information [Line Items]
Total Revenues	1,146,117	1,023,827	3,008,300	2,792,606
Building Materials Business | Operating Segments
Product Information [Line Items]
Total Revenues	1,146,117	1,023,827	3,008,300	2,792,606
Gross profit (loss)	287,816	268,322	661,343	643,668
Building Materials Business | Operating Segments | Products and Services
Product Information [Line Items]
Total Revenues	1,073,853	962,598	2,822,910	2,621,728
Gross profit (loss)	287,863	267,310	660,911	641,628
Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total Revenues	73,523	63,905	215,747	202,510
Gross profit (loss)	25,747	19,910	73,476	65,849
Magnesia Specialties | Operating Segments | Products and Services
Product Information [Line Items]
Total Revenues	68,365	59,889	201,390	189,918
Gross profit (loss)	26,823	21,272	76,756	69,425
Aggregates | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	687,800	590,312	1,778,124	1,619,282
Gross profit (loss)	209,082	187,065	460,624	439,032
Cement | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	98,223	88,470	300,554	280,961
Gross profit (loss)	32,543	27,459	97,582	87,608
Ready Mixed Concrete | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	254,686	240,222	750,424	704,471
Gross profit (loss)	20,632	23,913	66,226	70,542
Asphalt and Paving | Building Materials Business | Operating Segments | Reportable Subsegments | Products and Services
Product Information [Line Items]
Total Revenues	99,983	110,973	199,489	215,652
Gross profit (loss)	25,606	28,873	36,479	44,446
Freight
Product Information [Line Items]
Total Revenues	77,422	65,245	199,747	183,470
Freight | Building Materials Business
Product Information [Line Items]
Total Revenues	72,264	61,229	185,390	170,878
Freight | Building Materials Business | Operating Segments
Product Information [Line Items]
Total Revenues	72,264	61,229	185,390	170,878
Gross profit (loss)	(47)	1,012	432	2,040
Freight | Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total Revenues	5,158	4,016	14,357	12,592
Gross profit (loss)	$ (1,076)	$ (1,362)	$ (3,280)	$ (3,576)

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Components of Change in Other Assets and Liabilities Net (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Other current and noncurrent assets	$ (32,572)	$ (29,342)
Accrued salaries, benefits and payroll taxes	5,986	(6,234)
Accrued insurance and other taxes	4,555	10,230
Accrued income taxes	6,220	16,393
Accrued pension, postretirement and postemployment benefits	(131,963)	(5,807)
Other current and noncurrent liabilities	2,769	49,244
Change in other assets and liabilities, net	$ (145,005)	$ 34,484

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information - Schedule Of Noncash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Accrued liabilities for purchases of property, plant and equipment	$ 24,930	$ 20,339
Acquisition of assets through capital lease	$ 449	196
Settlement of royalty obligation via asset sale		$ 900

Supplemental Cash Flow Inform_5

Supplemental Cash Flow Information -Supplemental Disclosures of Cash Flow Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 84,522	$ 49,564
Cash paid for income taxes	$ 7,253	$ 96,643

Other Operating Expenses and In

Other Operating Expenses and Income, Net - Additional Information (Detail) - Other Operating Income, Net - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018
Component Of Other Income And Expense [Line Items]
Restructuring charge	$ 7,113,000
Net gain on legal settlements			$ 7,677,000
Gain on sale of surplus land			$ 16,938,000
Repair costs related to leased railcars		$ 12,425,000