Martin Marietta Materials (MLM) 10-K 23 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 09, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	MLM
Entity Registrant Name	MARTIN MARIETTA MATERIALS INC
Entity Central Index Key	916,076
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock Shares Outstanding		62,803,002
Entity Public Float			$ 11,664,571,328

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net Sales	$ 3,721,428,000	$ 3,576,767,000	$ 3,268,116,000
Freight and delivery revenues	244,166,000	241,982,000	271,454,000
Total revenues	3,965,594,000	3,818,749,000	3,539,570,000
Cost of sales	2,749,488,000	2,665,029,000	2,541,196,000
Freight and delivery costs	244,166,000	241,982,000	271,454,000
Total cost of revenues	2,993,654,000	2,907,011,000	2,812,650,000
Gross Profit	971,940,000	911,738,000	726,920,000
Selling, general and administrative expenses	262,128,000	241,606,000	210,754,000
Acquisition-related expenses	8,638,000	909,000	6,346,000
Other operating expenses and (income), net	793,000	(8,043,000)	15,653,000
Earnings from Operations	700,381,000	677,266,000	494,167,000
Interest expense	91,487,000	81,677,000	76,287,000
Other nonoperating (income) and expenses, net	(10,034,000)	(11,439,000)	4,079,000
Earnings before income tax (benefit) expense	618,928,000	607,028,000	413,801,000
Income tax (benefit) expense	(94,457,000)	181,584,000	124,863,000
Consolidated net earnings	713,385,000	425,444,000	288,938,000
Less: Net earnings attributable to noncontrolling interests	43,000	58,000	146,000
Net Earnings Attributable to Martin Marietta	$ 713,342,000	$ 425,386,000	$ 288,792,000
Net Earnings Attributable to Martin Marietta Per Common Share (see Note A)
Basic attributable to common shareholders	$ 11.30	$ 6.66	$ 4.31
Diluted attributable to common shareholders	$ 11.25	$ 6.63	$ 4.29
Weighted-Average Common Shares Outstanding
Basic	62,932	63,610	66,770
Diluted	63,217	63,861	67,020

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Consolidated Net Earnings	$ 713,385	$ 425,444	$ 288,938
Defined benefit pension and postretirement plans:
Net loss arising during period, net of tax of $(2,625), $(19,734) and $(4,530), respectively	(8,052)	(31,620)	(7,101)
Amortization of prior service credit, net of tax of $(547), $(617) and $(731), respectively	(883)	(992)	(1,149)
Amortization of actuarial loss, net of tax of $5,271, $4,437 and $6,551, respectively	8,503	7,138	10,299
Amount recognized in net periodic pension cost due to settlement, net of tax of $8, $44 and $0 respectively	13	71
Amount recognized in net periodic pension cost due to special plan termination benefits, net of tax of $0, $293 and $811, respectively		471	1,274
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(419)	(24,932)	3,323
Foreign currency translation gain (loss)	1,140	(898)	(3,542)
Amortization of terminated value of forward starting interest rate swap agreements into interest expense, net of tax of $571, $541 and $509, respectively	872	826	771
Other Comprehensive Income (Loss), Net of Tax	1,593	(25,004)	552
Consolidated comprehensive earnings	714,978	400,440	289,490
Less: Comprehensive earnings attributable to noncontrolling interests	53	119	161
Comprehensive Earnings Attributable to Martin Marietta	$ 714,925	$ 400,321	$ 289,329

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Earnings (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss arising during period, tax	$ (2,625)	$ (19,734)	$ (4,530)
Amortization of prior service credit, tax	(547)	(617)	(731)
Amortization of actuarial loss, tax	5,271	4,437	6,551
Amount recognized in net periodic pension cost due to settlement, tax	8	44	0
Amount recognized in net periodic pension cost due to special plan termination benefits, tax	0	293	811
Amortization of terminated value of forward starting interest rate swap agreements into interest expense, tax	$ 571	$ 541	$ 509

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 1,446,364	$ 50,038
Accounts receivable, net	487,240	457,910
Inventories, net	600,591	521,624
Other current assets	96,965	56,813
Total Current Assets	2,631,160	1,086,385
Property, plant and equipment, net	3,592,813	3,423,395
Goodwill	2,160,290	2,159,337
Operating permits, net	439,116	442,202
Other intangibles, net	67,233	69,110
Other noncurrent assets	101,899	120,476
Total Assets	8,992,511	7,300,905
Current Liabilities:
Accounts payable	183,638	178,598
Accrued salaries, benefits and payroll taxes	44,255	47,428
Pension and postretirement benefits	13,652	9,293
Accrued insurance and other taxes	64,958	60,093
Current maturities of long-term debt	299,909	180,036
Other current liabilities	87,804	71,140
Total Current Liabilities	694,216	546,588
Long-term debt	2,727,294	1,506,153
Pension, postretirement and postemployment benefits	244,043	248,086
Deferred income taxes, net	410,723	663,019
Other noncurrent liabilities	233,758	194,469
Total Liabilities	4,310,034	3,158,315
Equity:
Common stock ($0.01 par value; 100,000,000 shares authorized; 62,873,000 and 63,176,000 shares outstanding at December 31, 2017 and 2016, respectively)	628	630
Preferred stock ($0.01 par value; 10,000,000 shares authorized; no shares outstanding)
Additional paid-in capital	3,368,007	3,334,461
Accumulated other comprehensive loss	(129,104)	(130,687)
Retained earnings	1,440,069	935,574
Total Shareholders’ Equity	4,679,600	4,139,978
Noncontrolling interests	2,877	2,612
Total Equity	4,682,477	4,142,590
Total Liabilities and Equity	$ 8,992,511	$ 7,300,905

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares outstanding	62,873,000	62,873,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares outstanding	0	0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Consolidated net earnings	$ 713,385	$ 425,444	$ 288,938
Adjustments to reconcile consolidated net earnings to net cash provided by operating activities:
Depreciation, depletion and amortization	297,162	285,253	263,587
Stock-based compensation expense	30,460	20,481	13,589
(Gain) Loss on divestitures and sales of assets	(19,366)	410	14,093
Deferred income taxes, net	(239,056)	67,050	85,225
Other items, net	(13,157)	(17,730)	(5,972)
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable, net	(29,329)	(25,072)	12,309
Inventories, net	(78,966)	(47,381)	(21,525)
Accounts payable	(17,874)	(8,116)	(40,053)
Other assets and liabilities, net	14,619	(11,106)	(29,591)
Net Cash Provided by Operating Activities	657,878	689,233	580,600
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(410,325)	(387,267)	(318,232)
Acquisitions	(12,095)	(178,768)	(43,215)
Cash received in acquisition		4,246	63
Proceeds from divestitures and sales of assets	35,941	6,476	448,122
Payment of railcar construction advances	(43,594)	(82,910)	(25,234)
Reimbursement of railcar construction advances	43,594	82,910	25,234
Repayments from affiliate			1,808
Net Cash (Used for) Provided by Investing Activities	(386,479)	(555,313)	88,546
Cash Flows from Financing Activities:
Borrowings of long-term debt	2,408,830	560,000	230,000
Repayments of long-term debt	(1,065,048)	(449,306)	(244,704)
Payments of deferred acquisition consideration	(2,774)
Debt issuance costs	(2,204)	(2,300)
Change in bank overdraft		(10,235)	10,052
Payments on capital lease obligations	(3,543)	(3,364)	(6,616)
Dividends paid	(108,852)	(105,036)	(107,462)
Distributions to owners of noncontrolling interest		(400)	(325)
Contributions by noncontrolling interest to joint venture	212	44
Repurchase of common stock	(99,999)	(259,228)	(519,962)
Proceeds from exercise of stock options	10,110	27,257	37,230
Shares withheld for employees' income tax obligations	(11,805)	(9,723)	(7,601)
Net Cash Provided by (Used for) Financing Activities	1,124,927	(252,291)	(609,388)
Net Increase (Decrease) in Cash and Cash Equivalents	1,396,326	(118,371)	59,758
Cash and Cash Equivalents, beginning of year	50,038	168,409	108,651
Cash and Cash Equivalents, end of year	$ 1,446,364	$ 50,038	$ 168,409

Consolidated Statements of Tota

Consolidated Statements of Total Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Earnings	Retained Earnings	Total Shareholders' Equity	Noncontrolling Interests
Beginning Balance at Dec. 31, 2014	$ 4,352,748	$ 671	$ 3,243,619	$ (106,159)	$ 1,213,035	$ 4,351,166	$ 1,582
Beginning Balance (in shares) at Dec. 31, 2014		67,293,000
Consolidated net earnings	288,938				288,792	288,792	146
Other comprehensive (loss) earnings	552			537		537	15
Dividends declared ($1.60 in 2015 and $1.64 in 2016 & 1.72 in 2017 per common share)	(107,462)				(107,462)	(107,462)
Issuances of common stock for stock award plans	30,624	$ 5	30,619			30,624
Issuances of common stock for stock award plans (in shares)		471,000
Repurchases of common stock	$ (519,962)	$ (33)			(519,929)	(519,962)
Repurchases of common stock, Shares	(3,285,380)	(3,285,000)
Stock-based compensation expense	$ 13,589		13,589			13,589
Noncontrolling interest acquired from business combination	1,475						1,475
Purchase of subsidiary shares from noncontrolling interest	(325)						(325)
Ending Balance at Dec. 31, 2015	4,060,177	$ 643	3,287,827	(105,622)	874,436	4,057,284	2,893
Ending Balance (in shares) at Dec. 31, 2015		64,479,000
Consolidated net earnings	425,444				425,386	425,386	58
Other comprehensive (loss) earnings	(25,004)			(25,065)		(25,065)	61
Dividends declared ($1.60 in 2015 and $1.64 in 2016 & 1.72 in 2017 per common share)	(105,036)				(105,036)	(105,036)
Issuances of common stock for stock award plans	26,112	$ 3	26,109			26,112
Issuances of common stock for stock award plans (in shares)		285,000
Repurchases of common stock	$ (259,228)	$ (16)			(259,212)	(259,228)
Repurchases of common stock, Shares	(1,587,987)	(1,588,000)
Stock-based compensation expense	$ 20,481		20,481			20,481
Distributions to owners of noncontrolling interests	(400)						(400)
Contribution from owners of noncontrolling interest	44		44			44
Ending Balance at Dec. 31, 2016	$ 4,142,590	$ 630	3,334,461	(130,687)	935,574	4,139,978	2,612
Ending Balance (in shares) at Dec. 31, 2016	62,873,000	63,176,000
Consolidated net earnings	$ 713,385				713,342	713,342	43
Other comprehensive (loss) earnings	1,593			1,583		1,583	10
Dividends declared ($1.60 in 2015 and $1.64 in 2016 & 1.72 in 2017 per common share)	(108,852)				(108,852)	(108,852)
Issuances of common stock for stock award plans	14,893	$ 2	14,891			14,893
Issuances of common stock for stock award plans (in shares)		155,000
Shares withheld for employees' income tax obligations	(11,805)		(11,805)			(11,805)
Repurchases of common stock	$ (99,999)	$ (4)			(99,995)	(99,999)
Repurchases of common stock, Shares	(457,742)	(458,000)
Stock-based compensation expense	$ 30,460		30,460			30,460
Contribution from owners of noncontrolling interest	212						212
Ending Balance at Dec. 31, 2017	$ 4,682,477	$ 628	$ 3,368,007	$ (129,104)	$ 1,440,069	$ 4,679,600	$ 2,877
Ending Balance (in shares) at Dec. 31, 2017	62,873,000	62,873,000

Consolidated Statements of Tot9

Consolidated Statements of Total Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Stockholders Equity [Abstract]
Cash dividends declared per common share	$ 1.72	$ 1.64	$ 1.60

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Accounting Policies	Notes to Financial Statements Note A: 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 282 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 markets where the Company has a leading aggregates position. Specifically, the Company has two cement plants in Texas, five cement distribution facilities and 152 ready mixed concrete and asphalt plants in Texas, Colorado, Louisiana and Arkansas. 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. As of December 31, 2017, the Building Materials business contains the following reportable segments: Mid-America Group, Southeast Group and West Group. The Mid-America Group operates in Indiana, Iowa, northern Kansas, Kentucky, Maryland, Minnesota, Missouri, eastern Nebraska, North Carolina, Ohio, South Carolina, Virginia, Washington and West Virginia. The Southeast Group has operations in Alabama, Florida, Georgia, Tennessee, Nova Scotia and the Bahamas. The West Group operates in Arkansas, Colorado, southern Kansas, Louisiana, western Nebraska, Nevada, Oklahoma, Texas, Utah and Wyoming. The following states accounted for 74% of the Building Materials business’ 2017 net sales: Texas, Colorado, North Carolina, Iowa and Georgia. The Company also operates a Magnesia Specialties business, which produces magnesia-based chemical products used in industrial, agricultural and environmental applications, and dolomitic lime sold primarily to customers in the steel and mining industries. Magnesia Specialties’ production facilities are located in Ohio and Michigan, and products are shipped to customers worldwide. Use of Estimates. The preparation of the Company’s consolidated financial statements in conformity with accounting principles generally accepted in the United States (U.S. GAAP) requires management to make certain estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of revenues and expenses. Such estimates include the valuation of accounts receivable, inventories, goodwill, intangible assets and other long-lived assets and assumptions used in the calculation of income tax (benefit) expense, retirement and other postemployment benefits, and the allocation of the purchase price to the fair values of assets acquired and liabilities assumed as part of business combinations. These estimates and assumptions are based on management’s judgment. Management evaluates estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, and adjusts such estimates and assumptions when facts and circumstances dictate. Changes in credit, equity and energy markets and changes in construction activity increase the uncertainty inherent in certain estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from estimates. Changes in estimates, including those resulting from continuing changes in the economic environment, are reflected in the consolidated financial statements for the period in which the change in estimate occurs. Basis of Consolidation . The consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries. Partially-owned affiliates are either consolidated or accounted for at cost or as equity investments, depending on the level of ownership interest or the Company’s ability to exercise control over the affiliates’ operations. Intercompany balances and transactions have been eliminated in consolidation. Revenue Recognition . Total revenues include sales of materials and services provided to customers, net of discounts or allowances, if any, and include freight and delivery costs billed to customers. Revenues for product sales are recognized when risks associated with ownership have passed to unaffiliated customers. Typically, this occurs when finished products are shipped. Revenues derived from the paving business are recognized using the percentage-of-completion method under the revenue-cost approach. Under the revenue-cost approach, recognized contract revenue equals the total estimated contract revenue multiplied by the percentage of completion. Recognized costs equal the total estimated contract cost multiplied by the percentage of completion. The percentage of completion is determined by costs incurred to date as a percentage of total costs estimated for the project. Freight and Delivery Costs . Freight and delivery costs represent pass-through transportation costs incurred and paid by the Company to third-party carriers to deliver products to customers. These costs are then billed to the customers. Cash and Cash Equivalents . Cash equivalents are comprised of highly-liquid instruments with original maturities of three months or less from the date of purchase. The Company manages its cash and cash equivalents to ensure short-term operating cash needs are met and excess funds are managed efficiently. When operating cash is not sufficient to meet current needs, the Company borrows money under its existing credit facilities. The Company utilizes excess cash to either pay down credit facility borrowings or invest in money market funds, money market demand deposit accounts or offshore time deposit accounts. Money market demand deposits and offshore time deposit accounts are exposed to bank solvency risk. Customer Receivables. Customer receivables are stated at cost. The Company does not typically charge interest on customer accounts receivables. The Company records an allowance for doubtful accounts, which includes a provision for probable losses based on historical write offs and a specific reserve for accounts deemed at risk. The Company writes off customer receivables as bad debt expense when it becomes probable based upon customer facts and circumstances that such amounts will not be collected. Inventories Valuation . Inventories are stated at the lower of cost or net realizable value. Costs for finished products and in process inventories are determined by the first-in, first-out method. Carrying value for expendable parts and supplies are determined by the weighted-average cost method. The Company records an allowance for finished product inventories based on an analysis of inventory on hand in excess of historical sales for a twelve-month or five year average period and future demand. The Company also establishes an allowance for expendable parts over five years old and supplies over one year old. Post-production stripping costs, which represent costs of removing overburden and waste materials to access mineral deposits, are a component of inventory production costs and recognized in cost of sales in the same period as the revenue from the sale of the inventory. Property, Plant and Equipment . Property, plant and equipment are stated at cost. The estimated service lives for property, plant and equipment are as follows: Class of Assets Range of Service Lives Buildings 5 to 20 years Machinery & Equipment 2 to 20 years Land Improvements 5 to 60 years The Company begins capitalizing quarry development costs at a point when reserves are determined to be proven or probable, economically mineable and when demand supports investment in the market. Capitalization of these costs ceases when production commences. Capitalized quarry development costs are classified as land improvements and depreciated over the life of the reserves. The Company reviews relevant facts and circumstances to determine whether to capitalize or expense pre-production stripping costs when additional pits are developed at an existing quarry. If the additional pit operates in a separate and distinct area of the quarry, these costs are capitalized as quarry development costs and depreciated over the life of the uncovered reserves. Additionally, a separate asset retirement obligation is created for additional pits when the liability is incurred. Once a pit enters the production phase, all post-production stripping costs are charged to inventory production costs as incurred. Mineral reserves and mineral interests acquired in connection with a business combination are valued using an income approach over the life of the reserves. Depreciation is computed based on estimated service lives, principally using the straight-line method. Depletion of mineral reserves is calculated based on proven and probable reserves using the units-of-production method on a quarry-by-quarry basis. Property, plant and equipment are reviewed for impairment whenever facts and circumstances indicate that the carrying amount of an asset group may not be recoverable. An impairment loss is recognized if expected future undiscounted cash flows over the estimated remaining service life of the related asset are less than the asset’s carrying value. Repair and Maintenance Costs. Repair and maintenance costs that do not substantially extend the life of the Company’s plant and equipment are expensed as incurred. Goodwill and Intangible Assets. Goodwill represents the excess purchase price paid for acquired businesses over the estimated fair value of identifiable assets and liabilities. Other intangibles represent amounts assigned principally to contractual agreements and are amortized ratably over periods based on related contractual terms. The Company’s reporting units, which represent the level at which goodwill is tested for impairment, are based on the geographic segments of the Building Materials business. Goodwill is assigned to the respective reporting unit(s) based on the location of acquisitions at the time of consummation. Goodwill is tested for impairment by comparing the reporting unit’s fair value to its carrying value, which represents Step 1 of a two-step approach. However, prior to Step 1, the Company may perform an optional qualitative assessment and evaluate macroeconomic conditions, industry and market conditions, cost factors, overall financial performance and other business or reporting unit-specific events. If the Company concludes it is more-likely-than-not (i.e., a likelihood of more than 50%) that a reporting unit’s fair value is higher than its carrying value, the Company does not perform any further goodwill impairment testing for that reporting unit. Otherwise, it proceeds to Step 1 of its goodwill impairment analysis. The Company may bypass the qualitative assessment for any reporting unit in any period and proceed directly with the quantitative calculation in Step 1. If the reporting unit’s fair value exceeds its carrying value, no further calculation is necessary. A reporting unit with a carrying value in excess of its fair value constitutes a Step 1 failure and may lead to an impairment charge. The carrying values of goodwill and other indefinite-lived intangible assets are reviewed annually, as of October 1, for impairment. An interim review is performed between annual tests if facts and circumstances indicate potential impairment. The carrying value of other amortizable intangibles is reviewed if facts and circumstances indicate potential impairment. If a review indicates the carrying value is impaired, a charge is recorded. Retirement Plans and Postretirement Benefits. The Company sponsors defined benefit retirement plans and also provides other postretirement benefits. The Company recognizes the funded status, defined as the difference between the fair value of plan assets and the benefit obligation, of its pension plans and other postretirement benefits as an asset or liability on the consolidated balance sheets. Actuarial gains or losses that arise during the year are not recognized as net periodic benefit cost in the same year, but rather are recognized as a component of accumulated other comprehensive earnings or loss. Those amounts are amortized over the participants’ average remaining service period and recognized as a component of net periodic benefit cost. The amount amortized is determined using a corridor approach and represents the excess over 10% of the greater of the projected benefit obligation or pension plan assets. Stock-Based Compensation. The Company has stock-based compensation plans for employees and its Board of Directors. The Company recognizes all forms of stock-based awards that vest, including stock options, as compensation expense. The compensation expense is the fair value of the awards at the measurement date and is recognized over the requisite service period. The fair value of restricted stock awards, incentive compensation stock awards and Board of Directors’ fees paid in the form of common stock are based on the closing price of the Company’s common stock on the awards’ respective grant dates. The fair value of performance stock awards is determined by a Monte Carlo simulation methodology. In 2017 and 2016, the Company did not issue any stock options. For stock options issued prior to 2016, the Company used the accelerated expense recognition method. The accelerated recognition method requires stock options that vest ratably to be divided into tranches. The expense for each tranche is allocated to its particular vesting period. The Company uses the lattice valuation model to determine the fair value of stock option awards. The lattice valuation model takes into account employees’ exercise patterns based on changes in the Company’s stock price and other variables. The period of time for which options are expected to be outstanding is a derived output of the lattice valuation model and includes the following considerations: vesting period of the award, expected volatility of the underlying stock and employees’ ages. Key assumptions used in determining the fair value of the stock options awarded in 2015 were: Risk-free interest rate 2.20% Dividend yield 1.20% Volatility factor 36.10% Expected term 8.5 years Based on these assumptions, the weighted-average fair value of each stock option granted in 2015 was $57.71. The risk-free interest rate reflects the interest rate on zero-coupon U.S. government bonds, available at the time each option was granted, having a remaining life approximately equal to the option’s expected life. The dividend yield represents the dividend rate expected to be paid over the option’s expected life. The Company’s volatility factor measures the amount by which its stock price is expected to fluctuate during the expected life of the option and is based on historical stock price changes. Forfeitures are required to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company estimates forfeitures and will ultimately recognize compensation cost only for those stock-based awards that vest. Environmental Matters. The Company records a liability for an asset retirement obligation at fair value in the period in which it is incurred. The asset retirement obligation is recorded at the acquisition date of a long-lived tangible asset if the fair value can be reasonably estimated. A corresponding amount is capitalized as part of the asset’s carrying amount. The fair value is affected by management’s assumptions regarding the scope of the work required, inflation rates and quarry closure dates. Further, the Company records an accrual for other environmental remediation liabilities in the period in which it is probable that a liability has been incurred and the appropriate amounts can be estimated reasonably. Such accruals are adjusted as further information develops or circumstances change. Generally, these costs are not discounted to their present value or offset for potential insurance or other claims or potential gains from future alternative uses for a site. Income Taxes . Deferred income taxes, net, on the consolidated balance sheets reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, net of valuation allowances. The effect on deferred income tax assets and liabilities attributable to changes in enacted tax rates are charged or credited to income tax expense or benefit in the period of enactment. Uncertain Tax Positions. The Company recognizes a tax benefit when it is more-likely-than-not, based on the technical merits, that a tax position would be sustained upon examination by a taxing authority. The amount to be recognized is measured as the largest amount of tax benefit that is greater than 50% likely of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. The Company’s unrecognized tax benefits are recorded in other liabilities on the consolidated balance sheets or as an offset to the deferred tax asset for tax carryforwards where available. 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. Sales Taxes. Sales taxes collected from customers are recorded as liabilities until remitted to taxing authorities and therefore are not reflected in the consolidated statements of earnings. Start-Up Costs. Noncapital start-up costs for new facilities and products are charged to operations as incurred. Warranties. The Company’s construction contracts contain warranty provisions covering defects in materials, design or workmanship that generally run from nine months to one year after project completion. Due to the nature of its projects, including contract owner inspections of the work both during construction and prior to acceptance, the Company has not experienced material warranty costs for these short-term warranties and therefore does not believe an accrual for these costs is necessary. The ready mixed concrete product line carries a longer warranty period, 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 projects. These costs were not material to the Company’s consolidated results of operations for the years ended December 31, 2017, 2016 and 2015. Consolidated Comprehensive Earnings and Accumulated Other Comprehensive Loss . Consolidated comprehensive earnings for the Company consist of consolidated net earnings, 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 comprehensive earnings. Accumulated other comprehensive loss consists of unrecognized gains and losses related to the funded status of the pension and postretirement benefit plans, foreign currency translation and the unamortized value of terminated forward starting interest rate swap agreements, and is presented on the Company’s consolidated balance sheets. The components of the changes in accumulated other comprehensive loss and related cumulative noncurrent deferred tax assets are as follows: Pension and Postretirement Benefit Plans Foreign Currency Unamortized Value of Terminated Forward Starting Interest Rate Swap Total years ended December 31 (add 000) 2017 Accumulated other comprehensive loss at beginning of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Other comprehensive (loss) earnings before reclassifications, net of tax (8,062 ) 1,140 — (6,922 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 7,633 — 872 8,505 Other comprehensive (loss) earnings, net of tax (429 ) 1,140 872 1,583 Accumulated other comprehensive loss at end of period $ (128,802 ) $ (22 ) $ (280 ) $ (129,104 ) Cumulative noncurrent deferred tax assets at end of period $ 79,938 $ — $ 178 $ 80,116 2016 Accumulated other comprehensive loss at beginning of period $ (103,380 ) $ (264 ) $ (1,978 ) $ (105,622 ) Other comprehensive loss before reclassifications, net of tax (31,678 ) (898 ) — (32,576 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 6,685 — 826 7,511 Other comprehensive (loss) earnings, net of tax (24,993 ) (898 ) 826 (25,065 ) Accumulated other comprehensive loss at end of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Cumulative noncurrent deferred tax assets at end of period $ 82,044 $ — $ 749 $ 82,793 2015 Accumulated other comprehensive (loss) earnings at beginning of period $ (106,688 ) $ 3,278 $ (2,749 ) $ (106,159 ) Other comprehensive loss before reclassifications, net of tax (7,116 ) (3,542 ) — (10,658 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 10,424 — 771 11,195 Other comprehensive earnings (loss), net of tax 3,308 (3,542 ) 771 537 Accumulated other comprehensive loss at end of period $ (103,380 ) $ (264 ) $ (1,978 ) $ (105,622 ) Cumulative noncurrent deferred tax assets at end of period $ 66,467 $ — $ 1,290 $ 67,757 Reclassifications out of accumulated other comprehensive loss are as follows: years ended December 31 (add 000) 2017 2016 2015 Affected line items in the consolidated statements of earnings Pension and postretirement benefit plans Special plan termination benefits $ - $ 764 $ 2,085 Settlement charge 21 115 — Amortization of: Prior service credit (1,430 ) (1,609 ) (1,880 ) Actuarial loss 13,774 11,575 16,850 12,365 10,845 17,055 Other nonoperating (income) and expenses, net Tax effect (4,732 ) (4,160 ) (6,631 ) Income tax (benefit) expense Total $ 7,633 $ 6,685 $ 10,424 Unamortized value of terminated forward starting interest rate swap Additional interest expense $ 1,443 $ 1,367 $ 1,280 Interest expense Tax effect (571 ) (541 ) (509 ) Income tax (benefit) expense Total $ 872 $ 826 $ 771 Earnings Per Common Share . The Company computes earnings per share (EPS) pursuant to the two-class method. The two-class method determines EPS for each class of common stock and participating securities according to dividends or dividend equivalents and their respective participation rights in undistributed earnings. The Company pays nonforfeitable dividend equivalents during the vesting period on its restricted stock awards and incentive stock awards made prior to 2016, which results in these being considered participating securities. The numerator for basic and diluted earnings per common share is net earnings attributable to Martin Marietta, reduced by dividends and undistributed earnings attributable to the Company’s unvested restricted stock awards and incentive stock awards issued prior to 2016. 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 issued to employees and nonemployee members of the Company’s Board of Directors under certain stock-based compensation arrangements if the conversion is dilutive. The following table reconciles the numerator and denominator for basic and diluted earnings per common share: years ended December 31 (add 000) 2017 2016 2015 Net earnings attributable to Martin Marietta $ 713,342 $ 425,386 $ 288,792 Less: Distributed and undistributed earnings attributable to unvested awards 2,029 1,775 1,252 Basic and diluted net earnings attributable to common shareholders attributable to Martin Marietta $ 711,313 $ 423,611 $ 287,540 Basic weighted-average common shares outstanding 62,932 63,610 66,770 Effect of dilutive employee and director awards 285 251 250 Diluted weighted-average common shares outstanding 63,217 63,861 67,020 New Accounting Pronouncements . Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In March 2017, the Financial Accounting Standards Board (FASB) issued an accounting standards update (ASU), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost , Stock Compensation The FASB issued ASU Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting Pending Accounting Pronouncements. Revenue Recognition Standard The FASB issued ASU Revenue From Contracts with Customers Lease Standard In February 2016, the FASB issued a new accounting standard, Accounting Codification Standard 842 – Leases, In January 2018, the FASB issued ASU Land Easement Practical Expedient for Transition to Topic 842

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Note B: Goodwill and Other Intangible Assets The following table shows the changes in goodwill by reportable segment and in total. December 31 Mid- America Group Southeast Group West Group Total (add 000) 2017 Balance at beginning of period $ 281,403 $ 50,346 $ 1,827,588 $ 2,159,337 Acquisitions — — 230 230 Purchase price adjustments — — 723 723 Balance at end of period $ 281,403 $ 50,346 $ 1,828,541 $ 2,160,290 2016 Balance at beginning of period $ 281,403 $ 50,346 $ 1,736,486 $ 2,068,235 Acquisitions — — 91,174 91,174 Divestitures — — (72 ) (72 ) Balance at end of period $ 281,403 $ 50,346 $ 1,827,588 $ 2,159,337 Intangible assets subject to amortization consist of the following: December 31 Gross Amount Accumulated Amortization Net Balance (add 000) 2017 Noncompetition agreements $ 6,274 $ (6,144 ) $ 130 Customer relationships 45,755 (17,351 ) 28,404 Operating permits 458,952 (26,436 ) 432,516 Use rights and other 16,946 (10,377 ) 6,569 Trade names 12,800 (7,947 ) 4,853 Total $ 540,727 $ (68,255 ) $ 472,472 2016 Noncompetition agreements $ 6,274 $ (6,106 ) $ 168 Customer relationships 45,755 (13,636 ) 32,119 Operating permits 455,095 (19,493 ) 435,602 Use rights and other 16,946 (9,239 ) 7,707 Trade names 12,800 (5,681 ) 7,119 Total $ 536,870 $ (54,155 ) $ 482,715 Intangible assets deemed to have an indefinite life and not being amortized consist of the following: December 31 Building Materials Business Magnesia Specialties Total (add 000) 2017 Operating permits $ 6,600 $ — $ 6,600 Use rights 24,432 — 24,432 Trade names 280 2,565 2,845 Total $ 31,312 $ 2,565 $ 33,877 2016 Operating permits $ 6,600 $ — $ 6,600 Use rights 19,152 — 19,152 Trade names 280 2,565 2,845 Total $ 26,032 $ 2,565 $ 28,597 During 2017, the Company acquired $10,270,000 of intangibles, consisting of the following: (add 000, except year data) Amount Weighted-average amortization period Subject to amortization: Operating permits $ 4,990 40 years Not subject to amortization: Use Rights 5,280 N/A Total $ 10,270 Total amortization expense for intangible assets for the years ended December 31, 2017, 2016 and 2015 was $14,178,000, $13,922,000 and $13,962,000, respectively. The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: (add 000) 2018 $ 13,070 2019 12,114 2020 12,078 2021 11,387 2022 9,805 Thereafter 414,018 Total $ 472,472

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Business Combinations	Note C: Business Combinations Completed Acquisitions. In February 2016, the Company acquired the outstanding stock of Rocky Mountain Materials and Asphalt, Inc. and Rocky Mountain Premix, Inc. The acquisition provides more than 500 million tons of mineral reserves and expands the Company’s presence along the Front Range of the Rocky Mountains, home to 80% of Colorado’s population. The acquired operations are reported within the West Group. In July 2016, the Company acquired the remaining interest in Ratliff Ready-Mix, L.P. (Ratliff), which operates ready mixed concrete plants in central Texas. These operations are reported in the West Group. Prior to the acquisition, the Company owned a 40% interest in Ratliff which was accounted for under the equity method. The Company was required to remeasure the existing 40% interest in Ratliff at fair value upon closing of the transaction, resulting in a gain of $5,863,000, which is recorded in other nonoperating income, net. The impact of these acquisitions on the operating results was not considered material; therefore, pro forma financial information is not included. Pending Acquisition of Bluegrass Materials. On June 26, 2017, the Company announced a definitive agreement to acquire Bluegrass Materials Company (Bluegrass) for $1,625,000,000 in cash. The Company will not acquire any of Bluegrass’ cash and cash equivalents nor will it assume any of Bluegrass’ outstanding debt. Bluegrass is the largest privately held, pure-play aggregates business in the United States and has a portfolio of 23 active sites with more than 125 years of strategically-located, high-quality reserves, in Maryland, Georgia, South Carolina, Kentucky, Tennessee and Pennsylvania. These operations complement the Company’s existing southeastern footprint and provide a new growth platform within the southern portion of the Northeast. The Company and Bluegrass are continuing to work closely and cooperatively with the Department of Justice in its review of the proposed transaction. The parties currently anticipate that the proposed acquisition will be completed in the first half of 2018. In 2017, the Company incurred acquisition-related expenses of $8,638,000 for this pending transaction.

Accounts Receivable, Net

Accounts Receivable, Net	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Accounts Receivable, Net	Note D: Accounts Receivable, Net December 31 (add 000) 2017 2016 Customer receivables $ 480,073 $ 456,508 Other current receivables 9,557 7,668 489,630 464,176 Less allowances (2,390 ) (6,266 ) Total $ 487,240 $ 457,910 Of the total accounts receivable, net, balances, $2,819,000 and $2,578,000 at December 31, 2017 and 2016, respectively, were due from unconsolidated affiliates.

Inventories, Net

Inventories, Net	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Inventories, Net	Note E: Inventories, Net December 31 (add 000) 2017 2016 Finished products $ 552,999 $ 479,291 Products in process and raw materials 62,761 61,171 Supplies and expendable parts 128,792 116,024 744,552 656,486 Less allowances (143,961 ) (134,862 ) Total $ 600,591 $ 521,624

Property, Plant and Equipment,

Property, Plant and Equipment, Net	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Property, Plant and Equipment, Net	Note F: Property, Plant and Equipment, Net December 31 (add 000) 2017 2016 Land and land improvements $ 974,622 $ 915,158 Mineral reserves and interests 1,162,289 1,114,560 Buildings 154,564 151,115 Machinery and equipment 4,006,619 3,766,975 Construction in progress 199,973 167,722 6,498,067 6,115,530 Less accumulated depreciation, depletion and amortization (2,905,254 ) (2,692,135 ) Total $ 3,592,813 $ 3,423,395 The gross asset value and accumulated amortization for machinery and equipment recorded under capital leases at December 31 were as follows: (add 000) 2017 2016 Machinery and equipment under capital leases $ 23,919 $ 23,117 Less accumulated amortization (11,243 ) (8,077 ) Total $ 12,676 $ 15,040 Depreciation, depletion and amortization expense related to property, plant and equipment was $279,808,000, $268,935,000 and $246,874,000 for the years ended December 31, 2017, 2016 and 2015, respectively. Depreciation, depletion and amortization expense includes amortization of machinery and equipment under capital leases. Interest cost of $3,616,000, $3,543,000 and $5,832,000 was capitalized during 2017, 2016 and 2015, respectively. At December 31, 2017 and 2016, $57,665,000 and $58,332,000, respectively, of the Building Materials business’ net property, plant and equipment were located in foreign countries, namely the Bahamas and Canada.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Long-Term Debt	Note G: Long-Term Debt December 31 (add 000) 2017 2016 6.60% Senior Notes, due 2018 $ 299,871 $ 299,483 4.25% Senior Notes, due 2024 395,814 395,252 7% Debentures, due 2025 124,180 124,090 3.450% Senior Notes, due 2027 296,628 - 3.500% Senior Notes, due 2027 494,352 - 6.25% Senior Notes, due 2037 228,033 227,975 4.250% Senior Notes, due 2047 591,688 - Floating Rate Senior Notes, due 2019, interest rate of 2.13% at December 31, 2017 298,102 - Floating Rate Senior Notes, due 2020, interest rate of 2.10% at December 31, 2017 298,227 - Floating Rate Senior Notes, due 2017, interest rate of 2.10% at December 31, 2016 - 299,033 Revolving Facility, due 2022, interest rate of 1.86% at December 31, 2016 - 160,000 Trade Receivable Facility, interest rate of 1.34% at December 31, 2016 - 180,000 Other notes 308 356 Total 3,027,203 1,686,189 Less current maturities (299,909 ) (180,036 ) Long-term debt $ 2,727,294 $ 1,506,153 The Company’s 6.60% Senior Notes due 2018, 7% Debentures due 2025, 6.25% Senior Notes due 2037, 4.25% Senior Notes due 2024, 3.450% Senior Notes due 2027, 3.500% Senior Notes due 2027, 4.250% Senior Notes due 2047, Floating Rate Senior Notes due 2019, and Floating Rate Senior Notes due 2020 (collectively, the “Senior Notes”) are senior unsecured obligations of the Company, ranking equal in right of payment with the Company’s existing and future unsubordinated indebtedness. Upon a change-of-control repurchase event and a resulting below-investment-grade credit rating, the Company would be required to make an offer to repurchase all outstanding Senior Notes, with the exception of the 7% Debentures due 2025, at a price in cash equal to 101% of the principal amount of the Senior Notes, plus any accrued and unpaid interest to, but not including, the purchase date. The Senior Notes are carried net of original issue discount, which is being amortized by the effective interest method over the life of the issue. With the exception of the Floating Rate Senior Notes due 2019 and the Floating Rate Senior Notes due 2020, the Senior Notes are redeemable prior to their respective maturity dates at a make-whole redemption price. The principal amount, effective interest rate and maturity date for the Company’s Senior Notes are as follows: Principal Amount (add 000) Effective Interest Rate Maturity Date 6.60% Senior Notes $ 300,000 6.81% April 15, 2018 4.25% Senior Notes $ 400,000 4.25% July 2, 2024 7% Debentures $ 125,000 7.12% December 1, 2025 3.450% Senior Notes $ 300,000 3.47% June 1, 2027 3.500% Senior Notes $ 500,000 3.53% December 15, 2027 6.25% Senior Notes $ 230,000 6.45% May 1, 2037 4.250% Senior Notes $ 600,000 4.27% December 15, 2047 Floating Rate Senior Notes, due 2019 $ 300,000 Three-month LIBOR + 0.50% December 20, 2019 Floating Rate Senior Notes, due 2020 $ 300,000 Three-month LIBOR + 0.65% May 22, 2020 On May 22, 2017, the Company issued $300,000,000 aggregate principal amount of Floating Rate Senior Notes due in 2020 (the “2020 Floating Rate Notes”) and $300,000,000 aggregate principal amount of 3.450% Senior Notes due in 2027 (the “3.450% Senior Notes”), unsecured obligations of the Company. The 3.450% Senior Notes may be redeemed in whole or in part prior to March 1, 2027 at a make-whole redemption price, or on or after March 1, 2027 at a redemption price equal to 100% of the principal amount of the notes to be redeemed, and in either case plus unpaid interest, if any, accrued thereon to, but excluding, the date of redemption. The 2020 Floating Rate Notes bear interest at a rate, reset quarterly, equal to the three-month London Interbank Offered Rate (LIBOR) for U.S. Dollars plus 0.65% (or 65 basis points) and may not be redeemed prior to their stated maturity date of May 22, 2020. On December 20, 2017, the Company issued $300,000,000 aggregate principal amount of Floating Rate Senior Notes due 2019 (the “2019 Floating Rate Notes”), $500,000,000 aggregate principal amount of 3.500% Senior Notes due 2027 (the “2027 3.500% Fixed Rate Notes”) and $600,000,000 aggregate principal amount of 4.250% Senior Notes due 2047 (the “2047 Fixed Rate Notes”), all of which are unsecured obligations of the Company and rank equally in right of payment with all of its existing and future unsubordinated indebtedness. The net proceeds of the offering are expected to be used to finance, in part, the previously-announced Bluegrass acquisition (the “Acquisition”) and to repay the $300,000,000 6.60% Senior Notes due April 15, 2018. The Company may not redeem the 2019 Floating Rate Notes prior to their stated maturity date of December 20, 2019. If the Acquisition is not consummated prior to September 30, 2018, the purchase agreement is terminated prior to September 30, 2018, or the Company publicly announces at any time prior to September 30, 2018 that it will no longer pursue the consummation of the Acquisition, the Company will be required to redeem all of the outstanding 2027 3.500% Fixed Rate Notes and the 2047 Fixed Rate Notes pursuant to a special mandatory redemption at a price equal to 101% of the aggregate principal amounts, plus accrued and unpaid interest. The 2019 Floating Rate Notes are not subject to the special mandatory redemption. The Company has a credit agreement 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 “Credit Agreement”), which provides for a $700,000,000 five-year senior unsecured revolving facility (the “Revolving Facility”). Borrowings under the Revolving Facility bear interest, at the Company’s option, at rates based upon LIBOR or a base rate, plus, for each rate, a margin determined in accordance with a ratings-based pricing grid. The Credit Agreement requires the Company’s ratio of consolidated net debt-to-consolidated earnings before interest, taxes, depreciation, depletion and amortization (EBITDA), as defined, 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 the quarter or 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 securitization facility (discussed later), consolidated debt, including debt for which the Company is a co-borrower (see Note N), 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. In December 2017, the Company amended its credit agreement to exclude debt obtained to fund the pending Bluegrass acquisition from the Ratio. The Company was in compliance with this Ratio at December 31, 2017. On December 5, 2017, the Company extended its Revolving Facility by one year. The Revolving Facility expires on December 5, 2022, with any outstanding principal amounts, together with interest accrued thereon, due in full on that date. The Company, through a wholly-owned special-purpose subsidiary, has a $300,000,000 trade receivable securitization facility (the “Trade Receivable Facility”). On September 27, 2017, the Company extended the maturity to September 26, 2018. 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. Borrowings are limited to the lesser of the facility limit or the borrowing base, as defined, of $338,784,000 and $332,302,000 at December 31, 2017 and 2016, respectively. These receivables are originated by the Company and then sold or contributed to the wholly-owned special-purpose subsidiary. The Company continues to be responsible for the servicing and administration of the receivables purchased by the wholly-owned special-purpose subsidiary. Borrowings under the Trade Receivable Facility bear interest at a rate equal to one-month LIBOR plus 0.725%, subject to change in the event that this rate no longer reflects the lender’s cost of lending. The Trade Receivable Facility contains a cross-default provision to the Company’s other debt agreements. The Company’s long-term debt maturities for the five years following December 31, 2017, and thereafter are: (add 000) 2018 $ 299,909 2019 298,157 2020 298,286 2021 65 2022 90 Thereafter 2,130,696 Total $ 3,027,203 The Company has a $5,000,000 short-term line of credit. No amounts were outstanding under this line of credit at December 31, 2017 or 2016. Accumulated other comprehensive loss includes the unamortized value of terminated forward starting interest rate swap agreements. For the years ended December 31, 2017, 2016 and 2015, the Company recognized $1,443,000, $ 1,367,000 and $1,280,000, respectively, as additional interest expense. The amortization of the terminated value of the forward starting interest rate swap agreements will be completed in April 2018 and will increase 2018 interest expense by approximately $463,000.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2017
Financial Instruments Disclosure [Abstract]
Financial Instruments	Note H: Financial Instruments The Company’s financial instruments include temporary cash investments, accounts receivable, notes receivable, bank overdraft, accounts payable, publicly-registered long-term notes, debentures and other long-term debt. Temporary cash investments are placed primarily in money market funds and money market demand deposit accounts with financial institutions. The Company’s cash equivalents have 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. Notes receivable are primarily promissory notes with customers and are not publicly traded. Management estimates that the fair value of notes receivable approximates its carrying amount. Bank overdraft represents amounts to be funded to financial institutions for checks that have cleared the bank. The estimated fair value of the bank overdraft approximates its carrying value. Accounts payable represent amounts owed to suppliers and vendors. The estimated fair value of accounts payable approximates its carrying amount due to the short-term nature of the payables. The carrying values and fair values of the Company’s long-term debt were $3,027,203,000 and $3,144,902,000, respectively, at December 31, 2017 and $1,686,189,000 and $1,752,338,000, respectively, at December 31, 2016. The estimated fair value of the Company’s publicly-registered long-term debt was estimated based on Level 2 of the fair value hierarchy using quoted market prices. The estimated fair values of other borrowings, which primarily represent variable-rate debt, approximate their carrying amounts as the interest rates reset periodically.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Note I: Income Taxes On December 22, 2017, the U.S. government enacted the Tax Cuts and Jobs Act of 2017 (the “2017 Tax Act”). The 2017 Tax Act is comprehensive legislation that includes provisions that lower the federal statutory corporate income tax rate from 35% to 21% beginning in 2018 and imposes a one-time transition tax on undistributed foreign earnings. U.S. GAAP The Company has recognized the net tax benefit related to the impact of the 2017 Tax Act for the remeasurement of deferred tax assets and liabilities and included this amount in its consolidated financial statements for the year ended December 31, 2017, on a provisional basis. The ultimate impact may differ from this provisional amount, possibly materially, due to among other things, additional analysis, changes in interpretations and assumptions the Company has made, and additional interpretive regulatory guidance that may be issued. The Company has not recorded a provisional amount to account for the transition tax on undistributed foreign earnings, as it is not expected to be material to its results of operations. In accordance with SAB 118, the Company may record additional provisional amounts during a measurement period not to extend beyond one year of the enactment date of the 2017 Tax Act. The accounting is expected to be complete when the Company’s 2017 U.S. corporate income tax return is filed in 2018 and any measurement period adjustments will be recognized as income tax expense or benefit in 2018. The components of the Company’s income tax (benefit) expense are as follows: years ended December 31 (add 000) 2017 2016 2015 Federal income taxes: Current $ 129,236 $ 97,975 $ 20,627 Deferred (239,304 ) 68,899 85,295 Total federal income tax (benefit) expense (110,068 ) 166,874 105,922 State income taxes: Current 14,843 15,189 18,153 Deferred (882 ) (1,149 ) 930 Total state income taxes 13,961 14,040 19,083 Foreign income taxes: Current 1,175 1,064 99 Deferred 475 (394 ) (241 ) Total foreign income taxes 1,650 670 (142 ) Income tax (benefit) expense $ (94,457 ) $ 181,584 $ 124,863 As discussed above, deferred tax expense for the year ended December 31, 2017 includes a tax benefit in the amount of $258,103,000 for the provisional impact of the 2017 Tax Act. The increase in 2016 federal current tax expense compared with 2015 is primarily attributable to an increase in earnings. For the years ended December 31, 2016 and 2015, the benefit related to the utilization of federal net operating loss (NOL) carryforwards, reflected in current tax expense, was $11,852,000 and $156,554,000, respectively. For the year ended December 31, 2016, excess tax benefits attributable to stock-based compensation transactions that were recorded to shareholders’ equity amounted to $6,792,000. For the year ended December 31, 2015, the realized tax benefit for stock-based compensation transactions was $871,000 less than the amounts estimated during the vesting periods, resulting in a decrease in the pool of excess tax credits. For the years ended December 31, 2017 and 2016, foreign pretax earnings were $10,566,000 and $3,865,000, respectively. For the year ended December 31, 2015 foreign pretax loss was $1,175,000. The Company’s effective income tax rate varied from the statutory United States income tax rate because of the following tax differences: years ended December 31 2017 2016 2015 Statutory tax rate 35.0 % 35.0 % 35.0 % (Reduction) increase resulting from: Provisional remeasurement of deferred taxes due to 2017 Tax Act (41.7 ) — — Effect of statutory depletion (5.6 ) (5.4 ) (7.8 ) State income taxes, net of federal tax benefit 1.5 1.5 3.0 Domestic production deduction (2.2 ) (2.0 ) (0.1 ) Stock based compensation (1.0 ) (0.1 ) (0.3 ) Other items (1.3 ) 0.9 0.4 Effective income tax rate (15.3%) 29.9 % 30.2 % The change in the effective income tax rate in 2017 compared with 2016 is attributable to the impact of the 2017 Tax Act. The statutory depletion deduction for all years is calculated as a percentage of sales, subject to certain limitations. Due to these limitations, the impact of changes in the sales volumes and earnings may not proportionately affect the Company’s statutory depletion deduction and the corresponding impact on the effective income tax rate. The growth in non-depletable income reduced the impact of the statutory depletion deduction on the effective income tax rate in 2017 and 2016 compared with 2015. The 2016 state tax impact on the effective income tax rate decreased compared with 2015 due to changes in apportionment of taxable income to states with lower tax rates and the reduction in certain states’ statutory tax rates. The Company is entitled to receive a 9% tax deduction related to income from domestic (i.e., United States) production activities. The deduction reduced income tax expense and increased consolidated net earnings by $15,461,000, or $0.25 per diluted share, in 2017; $13,583,000, or $0.21 per diluted share, in 2016; and $222,000, or less than $0.01 per diluted share, in 2015. The impact on the 2015 effective income tax rate was limited by the significant utilization of NOL carryforwards. The domestic production deduction was eliminated by the 2017 Tax Act and will not generate a tax benefit in future years. The principal components of the Company’s deferred tax assets and liabilities are as follows: December 31 Deferred Assets (Liabilities) (add 000) 2017 2016 Deferred tax assets related to: Employee benefits $ 16,059 $ 61,462 Inventories 56,242 71,490 Valuation and other reserves 22,989 38,206 Net operating loss carryforwards 11,780 10,507 Accumulated other comprehensive loss 80,116 82,793 AMT credit carryforward - 2,771 Gross deferred tax assets 187,186 267,229 Valuation allowance on deferred tax assets (10,349 ) (8,521 ) Total net deferred tax assets 176,837 258,708 Deferred tax liabilities related to: Property, plant and equipment (407,400 ) (635,576 ) Goodwill and other intangibles (168,506 ) (268,999 ) Other items, net (11,654 ) (17,152 ) Total deferred tax liabilities (587,560 ) (921,727 ) Deferred income taxes, net $ (410,723 ) $ (663,019 ) The Company had no domestic federal NOL carryforwards at December 31, 2017 and 2016. The Company had domestic state NOL carryforwards of $197,916,000 and $220,532,000 at December 31, 2017 and 2016, respectively. These carryforwards have various expiration dates through 2036. At December 31, 2017 and 2016, deferred tax assets associated with these carryforwards were $11,780,000 and $10,507,000, respectively, net of the federal benefit of the state deduction, for which valuation allowances of $10,085,000 and $8,303,000, respectively, were recorded. The Company also had domestic tax credit carryforwards of $1,342,000 and $1,441,000 at December 31, 2017 and 2016, respectively, which expire in 2031. At December 31, 2017 and 2016, deferred tax assets associated with these carryforwards were $1,060,000 and $937,000, respectively, net of the federal benefit of the state deduction, for which valuation allowances of $264,000 and $218,000, respectively, were recorded. At December 31, 2016, the Company also had an Alternative Minimum Tax credit carryforward of $17,192,000, which was fully utilized during 2017. The deferred tax asset associated with this carryforward, net of unrecognized tax benefits, was $2,771,000. Deferred tax liabilities for property, plant and equipment result from accelerated depreciation methods being used for income tax purposes as compared with the straight-line method for financial reporting purposes. Deferred tax liabilities related to goodwill and other intangibles reflect the cessation of goodwill amortization for financial reporting purposes, while amortization continues for income tax purposes. The Company provides deferred taxes, as required, on the undistributed net earnings of all non-U.S. subsidiaries for which the indefinite reversal criterion has not been met. The Company expects to permanently reinvest the earnings from its wholly-owned Canadian and Bahamian subsidiaries, and accordingly, has not provided deferred taxes on the subsidiaries’ undistributed net earnings. The wholly-owned Canadian subsidiary’s undistributed net earnings are estimated to be $43,587,000 at December 31, 2017. The determination of the unrecognized deferred tax liability for temporary differences related to the investment in the wholly-owned Canadian subsidiary is not practicable due to the lack of clarity in the tax repatriation statutes included in the 2017 Tax Act. The Bahamian subsidiary has no undistributed net earnings. The 2017 Tax Act requires mandatory deemed repatriation of undistributed foreign earnings, through a one-time transition tax based on post-1986 earnings and profits that were previously deferred from U.S. income taxes. The transition tax will be finalized during a measurement period not to extend beyond one year of the enactment date of the 2017 Tax Act. The Company does not believe the tax will be material to its results of operations . The 2017 Tax Act also changed the deduction allowed for executive compensation by expanding the definition of employees subject to the $1 million deduction limitation and by eliminating the exception from the limitation for performance-based compensation. The 2017 Tax Act includes a transition rule that exempts from these changes compensation provided pursuant to a written binding contract in effect on November 2, 2017. The Company has interpreted this transition rule such that there is no impact to its current provision or to its deferred tax assets recorded for employee benefits. However, should the Internal Revenue Service issue further guidance on what qualifies as a written binding contract, the Company may have to recognize additional tax expense. The following table summarizes the Company’s unrecognized tax benefits, excluding interest and correlative effects: years ended December 31 (add 000) 2017 2016 2015 Unrecognized tax benefits at beginning of year $ 21,807 $ 18,727 $ 21,107 Gross increases – tax positions in prior years 1,396 2,401 3,079 Gross decreases – tax positions in prior years (672 ) (1,924 ) (3,512 ) Gross increases – tax positions in current year 4,961 4,650 4,978 Gross decreases – tax positions in current year (946 ) (2,047 ) (594 ) Lapse of statute of limitations (4,179 ) - (6,331 ) Unrecognized tax benefits at end of year $ 22,367 $ 21,807 $ 18,727 At December 31, 2017, 2016 and 2015, unrecognized tax benefits of $10,399,000, $11,603,000 and $7,975,000, respectively, related to interest accruals and permanent income tax differences, net of federal tax benefits, would have favorably affected the Company’s effective income tax rate if recognized. Unrecognized tax benefits are reversed as a discrete event if an examination of applicable tax returns is not initiated by a federal or state tax authority within the statute of limitations or upon effective settlement with federal or state tax authorities. Management believes its accrual for unrecognized tax benefits is sufficient to cover uncertain tax positions reviewed during audits by taxing authorities. The Company anticipates that it is reasonably possible that its unrecognized tax benefits may decrease up to $3,333,000, excluding indirect benefits, during the twelve-months ending December 31, 2018, due to the expiration of the statute of limitations for the 2014 tax year. For the years ended December 31, 2017 and 2015, $3,922,000 or $0.06 per diluted share, and $2,364,000 or $0.04 per diluted share, respectively, were reversed into income upon the statute of limitations expiration for the 2010 through 2013 tax years. The Company’s open tax years subject to federal, state or foreign examinations are 2011 through 2017.

Retirement Plans, Postretiremen

Retirement Plans, Postretirement and Postemployment Benefits	12 Months Ended
	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Retirement Plans, Postretirement and Postemployment Benefits	Note J: Retirement Plans, Postretirement and Postemployment Benefits The Company sponsors defined benefit retirement plans that cover substantially all employees. Additionally, the Company provides other postretirement benefits for certain employees, including medical benefits for retirees and their spouses and retiree life insurance. Employees starting on or after January 1, 2002 are not eligible for postretirement welfare plans. The Company also provides certain benefits, such as disability benefits, to former or inactive employees after employment but before retirement. The measurement date for the Company’s defined benefit plans, postretirement benefit plans and postemployment benefit plans is December 31. Defined Benefit Retirement Plans. Retirement plan assets are invested in listed stocks, bonds, hedge funds, real estate and cash equivalents. Defined retirement benefits for salaried employees are based on each employee’s years of service and average compensation for a specified period of time before retirement. Defined retirement benefits for hourly employees are generally stated amounts for specified periods of service. The Company sponsors a Supplemental Excess Retirement Plan (SERP) that generally provides for the payment of retirement benefits in excess of allowable Internal Revenue Code limits. The SERP generally provides for a lump-sum payment of vested benefits. When these benefit payments exceed the sum of the service and interest costs for the SERP during a year, the Company recognizes a pro-rata portion of the SERP’s unrecognized actuarial loss as settlement expense. The net periodic retirement benefit cost of defined benefit plans includes the following components: years ended December 31 (add 000) 2017 2016 2015 Service cost $ 26,805 $ 22,167 $ 23,001 Interest cost 36,101 35,879 33,151 Expected return on assets (39,759 ) (37,699 ) (36,385 ) Amortization of: Prior service cost 311 350 422 Actuarial loss 14,138 12,074 17,159 Transition asset (1 ) (1 ) (1 ) Settlement charge 21 124 — Termination benefit charge — 764 2,085 Net periodic benefit cost $ 37,616 $ 33,658 $ 39,432 The components of net periodic benefit cost other than service cost are included in the line item Other nonoperating (income) and expenses, net The expected return on assets is a calculation based on applying an annually selected expected rate of return assumption to the estimated fair value of the plan assets, giving consideration to contributions and benefits paid. The termination benefit charge represents the increased benefits payable to former Texas Industries, Inc. (TXI) executives as part of their change-in-control agreements. The Company recognized the following amounts in consolidated comprehensive earnings: years ended December 31 (add 000) 2017 2016 2015 Actuarial loss $ 13,343 $ 52,028 $ 9,916 Amortization of: Prior service cost (311 ) (350 ) (422 ) Actuarial loss (14,138 ) (12,074 ) (17,159 ) Transition asset 1 1 1 Special plan termination benefits — (764 ) (2,085 ) Settlement charge (21 ) (124 ) — Net prior service cost — — 2,338 Total $ (1,126 ) $ 38,717 $ (7,411 ) Accumulated other comprehensive loss includes the following amounts that have not yet been recognized in net periodic benefit cost: December 31 2017 2016 (add 000) Gross Net of tax Gross Net of tax Prior service cost $ 115 $ 71 $ 425 $ 261 Actuarial loss 217,240 134,066 218,056 133,083 Transition asset (6 ) (4 ) (7 ) (4 ) Total $ 217,349 $ 134,133 $ 218,474 $ 133,340 The prior service cost, actuarial loss and transition asset expected to be recognized in net periodic benefit cost during 2018 are $104,000 (net of deferred taxes of $26,000), $13,184,000 (net of deferred taxes of $3,263,000) and $1,000, respectively. These amounts are included in accumulated other comprehensive loss at December 31, 2017. The defined benefit plans’ change in projected benefit obligation is as follows: years ended December 31 (add 000) 2017 2016 Net projected benefit obligation at beginning of year $ 831,849 $ 754,543 Service cost 26,805 22,167 Interest cost 36,101 35,879 Actuarial loss 56,675 49,760 Gross benefits paid (72,095 ) (30,500 ) Net projected benefit obligation at end of year $ 879,335 $ 831,849 The Company’s change in plan assets, funded status and amounts recognized on the Company’s consolidated balance sheets are as follows: years ended December 31 (add 000) 2017 2016 Change in plan assets: Fair value of plan assets at beginning of year $ 596,207 $ 546,512 Actual return on plan assets, net 83,091 35,432 Employer contributions 30,903 44,763 Gross benefits paid (72,095 ) (30,500 ) Fair value of plan assets at end of year $ 638,106 $ 596,207 December 31 (add 000) 2017 2016 Funded status of the plan at end of year $ (241,229 ) $ (235,642 ) Accrued benefit cost $ (241,229 ) $ (235,642 ) December 31 (add 000) 2017 2016 Amounts recognized on consolidated balance sheets consist of: Current liability $ (11,092 ) $ (6,223 ) Noncurrent liability (230,137 ) (229,419 ) Net amount recognized at end of year $ (241,229 ) $ (235,642 ) The accumulated benefit obligation for all defined benefit pension plans was $792,912,000 and $752,659,000 at December 31, 2017 and 2016, respectively. Benefit obligations and fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets are as follows: December 31 (add 000) 2017 2016 Projected benefit obligation $ 879,335 $ 831,849 Accumulated benefit obligation $ 792,912 $ 752,659 Fair value of plan assets $ 638,106 $ 596,207 Weighted-average assumptions used to determine benefit obligations as of December 31 are: 2017 2016 Discount rate 3.76% 4.29% Rate of increase in future compensation levels 4.50% 4.50% Weighted-average assumptions used to determine net periodic benefit cost for years ended December 31 are: 2017 2016 2015 Discount rate 4.29% 4.67% 4.25% Rate of increase in future compensation levels 4.50% 4.50% 4.50% Expected long-term rate of return on assets 6.75% 7.00% 7.00% The expected long-term rate of return on assets is based on a building-block approach, whereby the components are weighted based on the allocation of pension plan assets. For 2017 and 2016, the Company estimated the remaining lives of participants in the pension plans using the RP-2014 Base Table. The white-collar table was used for salaried participants and the blue-collar table, reflecting the experience of the Company’s participants, was used for hourly participants. The Company used mortality improvement scales MP-2017 and MP-2016 for the years 2017 and 2016, respectively. The change in mortality improvement scale in 2017 did not have a material impact on the projected benefit obligation. The target allocation for 2017 and the actual pension plan asset allocation by asset class are as follows: Percentage of Plan Assets 2017 December 31 Asset Class Target Allocation 2017 2016 Equity securities 54% 57% 57% Debt securities 30% 29% 28% Hedge funds 8% 7% 7% Real estate 8% 7% 8% Total 100% 100% 100% The Company’s investment strategy is for approximately 50% of equity securities to be invested in mid-sized to large capitalization U.S. funds, with the remaining invested in small capitalization, emerging markets and international funds. Debt securities, or fixed income investments, are invested in funds benchmarked to the Barclays U.S. Aggregate Bond Index. The fair values of pension plan assets by asset class and fair value hierarchy level are as follows: December 31 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value (add 000) 2017 Equity securities: Mid-sized to large cap $ — $ 177,497 $ — $ 177,497 Small cap, international and emerging growth funds — 186,272 — 186,272 Debt securities: Core fixed income — 182,225 — 182,225 Real estate — — 46,467 46,467 Hedge funds — — 45,604 45,604 Cash 41 — — 41 Total $ 41 $ 545,994 $ 92,071 $ 638,106 2016 Equity securities: Mid-sized to large cap $ — $ 169,176 $ — $ 169,176 Small cap, international and emerging growth funds — 169,678 — 169,678 Debt securities: Core fixed income — 168,282 — 168,282 Real estate — — 44,890 44,890 Hedge funds — — 44,036 44,036 Cash 145 — — 145 Total $ 145 $ 507,136 $ 88,926 $ 596,207 Real estate investments are stated at estimated fair value, which is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair values of real estate investments generally do not reflect transaction costs which may be incurred upon disposition of the real estate investments and do not necessarily represent the prices at which the real estate investments would be sold or repaid, since market prices of real estate investments can only be determined by negotiation between a willing buyer and seller. An independent valuation consultant is employed to determine the fair value of the real estate investments. The value of hedge funds is based on the values of the sub-fund investments. In determining the fair value of each sub-fund’s investment, the hedge funds’ Board of Trustees uses the values provided by the sub-funds and any other considerations that may, in its judgment, increase or decrease such estimated value. The change in the fair value of pension plan assets valued using significant unobservable inputs (Level 3) is as follows: years ended December 31 Real Estate Hedge Funds (add 000) 2017 Balance at beginning of year $ 44,890 $ 44,036 Purchases, sales, settlements, net (83 ) — Actual return on plan assets held at period end 1,660 1,568 Balance at end of year $ 46,467 $ 45,604 2016 Balance at beginning of year $ 23,242 $ 39,219 Purchases, sales, settlements, net 18,579 3,100 Actual return on plan assets held at period end 3,069 1,717 Balance at end of year $ 44,890 $ 44,036 In 2017 and 2016, the Company made combined pension plan and SERP contributions of $30,903,000 and $44,763,000, respectively. The Company currently estimates that it will contribute $37,400,000 to its pension and SERP plans in 2018. The expected benefit payments to be paid from plan assets for each of the next five years and the five-year period thereafter are as follows: (add 000) 2018 $ 43,090 2019 $ 40,894 2020 $ 43,143 2021 $ 44,568 2022 $ 46,359 Years 2023 - 2027 $ 261,475 Postretirement Benefits . The net periodic postretirement benefit credit cost for postretirement plans includes the following components: years ended December 31 (add 000) 2017 2016 2015 Service cost $ 80 $ 85 $ 137 Interest cost 727 863 928 Amortization of: Prior service credit (1,741 ) (1,959 ) (2,302 ) Actuarial gain (364 ) (499 ) (309 ) Settlement credit — (9 ) — Total net periodic benefit credit $ (1,298 ) $ (1,519 ) $ (1,546 ) The components of net periodic benefit credit other than service cost are included in the line item Other nonoperating (income) and expenses, net, The Company recognized the following amounts in consolidated comprehensive earnings: years ended December 31 (add 000) 2017 2016 2015 Actuarial loss (gain) $ 1,236 $ 686 $ (626 ) Net prior service credit (3,902 ) (1,326 ) — Settlement credit — 9 — Amortization of: Prior service credit 1,741 1,959 2,302 Actuarial gain 364 499 309 Total $ (561 ) $ 1,827 $ 1,985 Accumulated other comprehensive loss includes the following amounts that have not yet been recognized in net periodic benefit credit or cost: December 31 2017 2016 (add 000) Gross Net of tax Gross Net of tax Prior service credit $ (6,314 ) $ (3,899 ) $ (4,153 ) $ (2,551 ) Actuarial gain (2,256 ) (1,393 ) (3,857 ) (2,369 ) Total $ (8,570 ) $ (5,292 ) $ (8,010 ) $ (4,920 ) The prior service credit and actuarial gain expected to be recognized in net periodic benefit cost during 2018 is $2,445,000 (net of a deferred tax liability of $605,000) and $226,000 (net of a deferred tax liability of $56,000), respectively, and are included in accumulated other comprehensive loss at December 31, 2017. The postretirement health care plans’ change in benefit obligation is as follows: years ended December 31 (add 000) 2017 2016 Change in benefit obligation: Net benefit obligation at beginning of year $ 20,591 $ 23,408 Service cost 80 85 Interest cost 727 863 Participants’ contributions 3,421 2,616 Actuarial loss 1,236 688 Gross benefits paid (6,806 ) (5,743 ) Plan amendments (3,902 ) (1,326 ) Net benefit obligation at end of year $ 15,347 $ 20,591 The Company’s change in plan assets, funded status and amounts recognized on the Company’s consolidated balance sheets are as follows: years ended December 31 (add 000) 2017 2016 Fair value of plan assets at beginning of year $ — $ — Employer contributions 3,385 3,127 Participants’ contributions 3,421 2,616 Gross benefits paid (6,806 ) (5,743 ) Fair value of plan assets at end of year $ — $ — December 31 (add 000) 2017 2016 Funded status of the plan at end of year $ (15,347 ) $ (20,591 ) Accrued benefit cost $ (15,347 ) $ (20,591 ) December 31 (add 000) 2017 2016 Amounts recognized on consolidated balance sheets consist of: Current liability $ (2,560 ) $ (3,070 ) Noncurrent liability (12,787 ) (17,521 ) Net amount recognized at end of year $ (15,347 ) $ (20,591 ) Weighted-average assumptions used to determine the postretirement benefit obligations as of December 31 are: 2017 2016 Discount rate 3.47 % 3.78 % Weighted-average assumptions used to determine net postretirement benefit cost for the years ended December 31 are: 2017 2016 2015 Discount rate 3.78 % 4.25 % 3.83 % For 2017 and 2016, the Company estimated the remaining lives of participants in the pension plans using the RP-2014 Base Table. The white-collar table was used for salaried participants and the blue-collar table, reflecting the experience of the Company’s participants, was used for hourly participants. The Company used mortality improvement scales MP-2017 and MP-2016 for the years 2017 and 2016, respectively. The change in mortality improvement scale in 2017 did not have a material impact on the projected benefit obligation. Assumed health care cost trend rates at December 31 are: 2017 2016 Health care cost trend rate assumed for next year 7.0% 7.0% Rate to which the cost trend rate gradually declines 5.0% 5.0% Year the rate reaches the ultimate rate 2022 2021 Assumed health care cost trend rates have a significant effect on the amounts reported for the Company’s health care plans. A one percentage-point change in assumed health care cost trend rates would have the following effects: One Percentage Point (add 000) Increase (Decrease) Total service and interest cost components $ 41 $ (34 ) Postretirement benefit obligation $ 783 $ (631 ) The Company estimates that it will contribute $2,560,000 to its postretirement health care plans in 2018. The total expected benefit payments to be paid by the Company, net of participant contributions, for each of the next five years and the five-year period thereafter are as follows: (add 000) 2018 $ 2,560 2019 $ 1,610 2020 $ 1,557 2021 $ 1,470 2022 $ 1,393 Years 2023 - 2027 $ 4,888 Defined Contribution Plans . The Company maintains defined contribution plans that cover substantially all employees. These plans, qualified under Section 401(a) of the Internal Revenue Code, are retirement savings and investment plans for the Company’s salaried and hourly employees Under certain provisions of these plans, the Company, at established rates, matches employees’ eligible contributions. The Company’s matching obligations were $14,893,000 in 2017, $13,235,000 in 2016 and $12,444,000 in 2015. Postemployment Benefits. The Company had accrued postemployment benefits of $1,119,000 and $1,146,000 at December 31, 2017 and 2016, respectively.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note K: Stock-Based Compensation The shareholders approved, on May 19, 2016, the Martin Marietta Amended and Restated Stock-Based Award Plan. The Martin Marietta Materials, Inc. Stock-Based Award Plan, as amended from time to time (along with the Amended Omnibus Securities Award Plan, originally approved in 1994, the “Plans”) is still effective for awards made prior to 2017. The Company has been authorized by the Board of Directors to repurchase shares of the Company’s common stock for issuance under the stock-based award plans (see Note M). The Company grants restricted stock awards under the Plans to a group of executive officers, key personnel and nonemployee members of the Board of Directors. The vesting of certain restricted stock awards is based on certain performance criteria over a specified period of time. In addition, certain awards are granted to individuals to encourage retention and motivate key employees. These awards generally vest if the employee is continuously employed over a specified period of time and require no payment from the employee. Awards granted to nonemployee members of the Board of Directors vest immediately. Additionally, an incentive compensation stock plan has been adopted under the Plans whereby certain participants may elect to use up to 50% of their annual incentive compensation to acquire units representing shares of the Company’s common stock at a 20% discount to the market value on the date of the incentive compensation award. Certain executive officers are required to participate in the incentive compensation stock plan at certain minimum levels. Participants receive unrestricted shares of common stock in an amount equal to their respective units generally at the end of a 34-month period of additional employment from the date of award or at retirement beginning at age 62. All rights of ownership of the common stock convey to the participants upon the issuance of their respective shares at the end of the ownership-vesting period. The following table summarizes information for restricted stock awards and incentive compensation stock awards for 2017: Restricted Stock - Service Based Restricted Stock - Performance Based Incentive Compensation Stock Number of Awards Weighted- Average Grant-Date Fair Value Number of Awards Weighted- Average Grant-Date Fair Value Number of Awards Weighted- Average Grant-Date Fair Value January 1, 2017 307,317 $ 125.36 111,317 $ 122.22 40,549 $ 114.44 Awarded 80,181 $ 213.76 47,997 $ 207.73 19,981 $ 208.68 Distributed (68,828 ) $ 121.40 (17,692 ) $ 129.14 (21,784 ) $ 108.44 Forfeited (3,830 ) $ 156.40 (1,623 ) $ 150.38 (236 ) $ 124.41 December 31, 2017 314,840 $ 151.84 139,999 $ 150.34 38,510 $ 166.67 The weighted-average grant-date fair value of service-based restricted stock awards granted during 2017, 2016 and 2015 was $213.76, $128.48 and $154.26, respectively. The weighted-average grant-date fair value of performance-based restricted stock awards granted during 2017, 2016 and 2015 was $207.73, $124.41 and $108.53, respectively. The weighted-average grant-date fair value of incentive compensation stock awards granted during 2017, 2016 and 2015 was $208.68, $124.41 and $108.53, respectively. The aggregate intrinsic values for unvested restricted stock awards and unvested incentive compensation stock awards at December 31, 2017 were $100,538,000 and $3,377,000, respectively, and were based on the closing price of the Company’s common stock at December 31, 2017, which was $221.04. The aggregate intrinsic values of restricted stock awards distributed during the years ended December 31, 2017, 2016 and 2015 were $15,771,000, $9,738,000 and $11,387,000, respectively. The aggregate intrinsic values of incentive compensation stock awards distributed during the years ended December 31, 2017, 2016 and 2015 were $2,601,000, $1,941,000 and $983,000, respectively. The aggregate intrinsic values for distributed awards were based on the closing prices of the Company’s common stock on the dates of distribution. Under the Plans, prior to 2016, the Company granted options to employees to purchase its common stock at a price equal to the closing market value at the date of grant. Options become exercisable in four annual installments beginning one year after date of grant. Options granted starting 2013 expire ten years after the grant date while outstanding options granted prior to 2013 expire eight years after the grant date. In connection with the TXI acquisition, completed in 2014, the Company issued 821,282 Martin Marietta stock options (Replacement Options) to holders of outstanding TXI stock options at the acquisition date. The Company issued 0.7 Replacement Options for each outstanding TXI stock option, and the Replacement Option prices reflected the exchange ratio. The Replacement Options will expire on the original contractual dates when the TXI stock options were initially issued. Consistent with the terms of the Company’s other outstanding stock options, Replacement Options expire 90 days after employment is terminated. Prior to 2009, each nonemployee member of the Board of Directors received 3,000 non-qualified stock options annually. These options have an exercise price equal to the market value at the date of grant, vested immediately and expire ten years from the grant date. The following table includes summary information for stock options as of December 31, 2017: Number of Options Weighted- Average Exercise Price Weighted-Average Remaining Contractual Life (years) Outstanding at January 1, 2017 406,891 $ 93.27 Exercised (104,093 ) $ 98.68 Terminated (840 ) $ 80.52 Outstanding at December 31, 2017 301,958 $ 91.44 3.6 Exercisable at December 31, 2017 261,380 $ 83.37 3.1 The weighted-average grant-date exercise price of options granted during 2015 was $154.58. The aggregate intrinsic values of options exercised during the years ended December 31, 2017, 2016 and 2015 were $13,247,000, $22,571,000 and $7,318,000, respectively, and were based on the closing prices of the Company’s common stock on the dates of exercise. The aggregate intrinsic values for options outstanding and exercisable at December 31, 2017 were $39,135,000 and $35,984,000, respectively, and were based on the closing price of the Company’s common stock at December 31, 2017, which was $221.04. The excess tax benefits for stock options exercised during the years ended December 31, 2017, 2016 and 2015 were $3,483,000, $4,238,000 and $551,000, respectively. At December 31, 2017, there are approximately 836,000 awards available for grant under the Plans. In 2016, the Company’s shareholders approved the registration of an additional 800,000 shares of common stock under the Plans. As part of approving the registered shares, the Company agreed to not issue any additional awards under the legacy TXI plan. The awards available for grant under the Plans at December 31, 2017 reflect no awards available under the legacy TXI plan. In 1996, the Company adopted the Shareholder Value Achievement Plan to award shares of the Company’s common stock to key senior employees based on certain common stock performance criteria over a long-term period. Under the terms of this plan, 250,000 shares of common stock were reserved for issuance. Through December 31, 2017, 42,025 shares have been issued under this plan. No awards have been granted under this plan after 2000. The Company adopted and the shareholders approved the Common Stock Purchase Plan for Directors in 1996, which provides nonemployee members of the Board of Directors the election to receive all or a portion of their total fees in the form of the Company’s common stock. Beginning in 2016, members of the Board of Directors were not required to defer any of their fees in the form of the Company’s common stock. Under the terms of this plan, 300,000 shares of common stock were reserved for issuance. Nonemployee members of the Board of Directors elected to defer portions of their fees representing 2,132, 3,699 and 4,035 shares of the Company’s common stock under this plan during 2017, 2016 and 2015, respectively. The following table summarizes stock-based compensation expense for the years ended December 31, 2017, 2016 and 2015, unrecognized compensation cost for nonvested awards at December 31, 2017 and the weighted-average period over which unrecognized compensation cost will be recognized: (add 000, except year data) Stock Options Restricted Stock Incentive Compensation Stock Directors’ Awards Total Stock-based compensation expense recognized for years ended December 31: 2017 $ 684 $ 28,657 $ 661 $ 458 $ 30,460 2016 $ 1,646 $ 17,747 $ 442 $ 646 20,481 2015 $ 2,679 $ 9,809 $ 376 $ 725 13,589 Unrecognized compensation cost at December 31, 2017: $ 292 $ 24,116 $ 458 $ — $ 24,866 Weighted-average period over which unrecognized compensation cost will be recognized: 1.1 years 2.0 years 1.6 years — . The following presents expected stock-based compensation expense in future periods for outstanding awards as of December 31, 2017: (add 000) 2018 $ 15,559 2019 8,299 2020 645 2021 269 2022 94 Total $ 24,866 Stock-based compensation expense is included in selling, general and administrative expenses in the Company’s consolidated statements of earnings.

Leases

Leases	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Leases	Note L: Leases Total lease expense for operating leases was $90,731,000, $85,945,000 and $80,417,000 for the years ended December 31, 2017, 2016 and 2015, respectively. The Company’s operating leases generally contain renewal and/or purchase options with varying terms. The Company has royalty agreements that generally require royalty payments based on tons produced or total sales dollars and also contain minimum payments. Total royalties, principally for leased properties, were $51,827,000, $55,257,000 and $53,658,000 for the years ended December 31, 2017, 2016 and 2015, respectively. The Company also has capital lease obligations for machinery and equipment. Future minimum lease and royalty commitments for all noncancelable agreements and capital lease obligations as of December 31, 2017 are as follows: (add 000) Capital Leases Operating Leases & Royalty Commitments 2018 $ 4,205 $ 121,234 2019 3,750 64,504 2020 2,247 58,731 2021 1,371 55,290 2022 913 52,781 Thereafter 3,993 345,860 Total 16,479 $ 698,400 Less: imputed interest (3,231 ) Present value of minimum lease payments 13,248 Less: current capital lease obligations (3,623 ) Long-term capital lease obligations $ 9,625 Of the total future minimum commitments, $204,418,000 relates to the Company’s contracts of affreightment.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Shareholders' Equity	Note M: Shareholders’ Equity The authorized capital structure of the Company includes 100,000,000 shares of common stock, with a par value of $0.01 a share. At December 31, 2017, approximately 1,986,000 common shares were reserved for issuance under stock-based award plans. Pursuant to authority granted by its Board of Directors, the Company can repurchase up to 20,000,000 shares of common stock. The Company repurchased 457,742, 1,587,987 and 3,285,380 shares of common stock during 2017, 2016 and 2015, respectively. At December 31, 2017, 14,668,891 shares of common stock were remaining under the Company’s repurchase authorization. In addition to common stock, the Company’s capital structure includes 10,000,000 shares of preferred stock with a par value of $0.01 a share. On October 21, 2006, the Board of Directors adopted a Rights Agreement (the “Rights Agreement”) and reserved 200,000 shares of Junior Participating Class B Preferred Stock for issuance. In accordance with the Rights Agreement, the Company issued a dividend of one right for each share of the Company’s common stock outstanding as of October 21, 2006, and one right continues to attach to each share of common stock issued thereafter. The rights will become exercisable if any person or group acquires beneficial ownership of 15% or more of the Company’s common stock. Once exercisable and upon a person or group acquiring 15% or more of the Company’s common stock, each right (other than rights owned by such person or group) entitles its holder to purchase, for an exercise price of $315 per share, a number of shares of the Company’s common stock (or in certain circumstances, cash, property or other securities of the Company) having a market value of twice the exercise price, and under certain conditions, common stock of an acquiring company having a market value of twice the exercise price. If any person or group acquires beneficial ownership of 15% or more of the Company’s common stock, the Company may, at its option, exchange the outstanding rights (other than rights owned by such acquiring person or group) for shares of the Company’s common stock or Company equity securities deemed to have the same value as one share of common stock or a combination thereof, at an exchange ratio of one share of common stock per right. The Company’s Rights Agreement expired on October 21, 2016.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note N: 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 (see Note A), 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. Asset Retirement Obligations. The Company incurs reclamation and teardown costs as part of its mining and production processes. Estimated future obligations are discounted to their present value and accreted to their projected future obligations via charges to operating expenses. Additionally, the fixed assets recorded concurrently with the liabilities are depreciated over the period until retirement activities are expected to occur. Total accretion and depreciation expenses for 2017, 2016 and 2015 were $8,682,000, $8,823,000 and $6,767,000, respectively, and are included in other operating income and expenses, net, in the consolidated statements of earnings. The following shows the changes in the asset retirement obligations: years ended December 31: (add 000) 2017 2016 Balance at beginning of year $ 101,106 $ 89,604 Accretion expense 4,768 4,288 Liabilities incurred and liabilities assumed in business combinations 7,940 6,700 Liabilities settled (309 ) 166 Revisions in estimated cash flows (3,852 ) 348 Balance at end of year $ 109,653 $ 101,106 Other Environmental Matters . The Company’s operations are subject to and affected by federal, state and local laws and regulations relating to the environment, health and safety and other regulatory matters. Certain of the Company’s operations may, from time to time, involve the use of substances that are classified as toxic or hazardous within the meaning of these laws and regulations. Environmental operating permits are, or may be, required for certain of the Company’s operations, and such permits are subject to modification, renewal and revocation. The Company regularly monitors and reviews its operations, procedures and policies for compliance with these laws and regulations. Despite these compliance efforts, risk of environmental remediation liability is inherent in the operation of the Company’s businesses, as it is with other companies engaged in similar businesses. The Company has no material provisions for environmental remediation liabilities and does not believe such liabilities will have a material adverse effect on the Company in the future. The United States Environmental Protection Agency (EPA) includes the lime industry as a national enforcement priority under the federal Clean Air Act (CAA). As part of the industry-wide effort, the EPA issued Notices of Violation/Findings of Violation (NOVs) to the Company in 2010 and 2011 regarding its compliance with the CAA New Source Review (NSR) program at its Magnesia Specialties dolomitic lime manufacturing plant in Woodville, Ohio. The Company has been providing information to the EPA in response to these NOVs and has had several meetings with the EPA. Although the Company believes it is in substantial compliance with the NSR program, it anticipates that it will reach a settlement of this matter with the EPA. The Company believes any costs related to any required upgrades to capital equipment will be spread over time and that those costs and any related penalties will not have a material adverse effect on the Company’s results of operations or its financial condition. Insurance Reserves. The Company has insurance coverage with large deductibles for workers’ compensation, automobile liability, marine liability and general liability claims. The Company is also self-insured for health claims. At December 31, 2017 and 2016, reserves of $48,061,000 and $42,184,000, respectively, were recorded for all such insurance claims. The Company carries various risk deductible workers’ compensation policies related to its workers’ compensation liabilities. The Company records the workers’ compensation reserves based on an actuarial-determined analysis. This analysis calculates development factors, which are applied to total reserves within the workers’ compensation program. While the Company believes the assumptions used to calculate these liabilities are appropriate, significant differences in actual experience and/or significant changes in these assumptions may materially affect workers’ compensation costs. Letters of Credit. In the normal course of business, the Company provides certain third parties with standby letter of credit agreements guaranteeing its payment for certain insurance claims, contract performance and permit requirements. At December 31, 2017, the Company was contingently liable for $45,028,000 in letters of credit, of which $2,301,000 were issued under the Company’s Revolving Facility. The obligations for insurance claims are accrued on the Company’s consolidated balance sheets. Surety Bonds. In the normal course of business, at December 31, 2017, the Company was contingently liable for $348,253,000 in surety bonds required by certain states and municipalities and their related agencies. The bonds are principally for certain insurance claims, construction contracts, reclamation obligations and mining permits guaranteeing the Company’s own performance. Certain of these underlying obligations, including those for asset retirement requirements and insurance claims, are accrued on the Company’s consolidated balance sheets. Five of these bonds total $90,625,000, or 26%, of all outstanding surety bonds. The Company has indemnified the underwriting insurance companies, Liberty Mutual and W.R. Berkley, against any exposure under the surety bonds. In the Company’s past experience, no material claims have been made against these financial instruments. Borrowing Arrangements with Affiliate. The Company is a co-borrower with an unconsolidated affiliate for a revolving line of credit agreement with BB&T, of which $15,775,000 was outstanding as of December 31, 2017. The line of credit was amended in January 2018 to extend the maturity to March 2020 and reduce the line of credit from $25,000,000 to $15,500,000. 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 2014, the Company loaned the unconsolidated affiliate a total of $6,000,000 as an interest-only note due December 31, 2019. Purchase Commitments. The Company had purchase commitments for property, plant and equipment of $191,582,000 as of December 31, 2017. The Company also had other purchase obligations related to energy and service contracts of $123,883,000 as of December 31, 2017. The Company’s contractual purchase commitments as of December 31, 2017 are as follows: (add 000) 2018 $ 238,280 2019 37,275 2020 10,983 2021 8,809 2022 1,616 Thereafter 18,502 Total $ 315,465 Capital expenditures in 2017, 2016 and 2015 that were purchase commitments as of the prior year end were $83,748,000, $62,927,000 and $116,681,000, respectively. Employees. Approximately 11% of the Company’s employees are represented by a labor union. All such employees are hourly 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, located in Manistee, Michigan and Woodville, Ohio, 100% of its hourly employees are represented by labor unions. The Manistee collective bargaining agreement expires in August 2019. The Woodville collective bargaining agreement expires in May 2018.

Segments

Segments	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segments	Note O: Segments The Building Materials business is comprised of divisions which represent operating segments. Certain divisions are consolidated into reportable segments for financial reporting purposes as they meet the aggregation criteria. The Building Materials business contains three reportable segments: Mid-America Group, Southeast Group and West Group. The Magnesia Specialties business represents an individual operating and reportable segment. The accounting policies used for segment reporting are the same as those described in Note A. The Company’s evaluation of performance and allocation of resources are based primarily on earnings from operations. Consolidated earnings from operations include net sales less cost of sales, selling, general and administrative expenses, acquisition-related expenses, other operating income and expenses, net, and exclude interest expense, other nonoperating income and expenses, net, and tax expense/benefit. Corporate consolidated earnings from operations primarily include depreciation on capitalized interest, expenses for corporate administrative functions, acquisition-related expenses, net, and other nonrecurring and/or non-operational income and expenses excluded from the Company’s evaluation of segment performance and resource allocation. All long-term debt and related interest expense areheld at Corporate. Assets employed by segment include assets directly identified with those operations. Corporate assets consist primarily of cash and cash equivalents; property, plant and equipment for corporate operations; investments and other assets not directly identifiable with a reportable segment. In connection with a management change effective January 1, 2017, the cement product line is reported in the West Group. All segment information has been reclassified to conform to the presentation of the Company’s current reportable segments and for the adoption of ASU 2017-07. The following tables display selected financial data for the Company’s reportable segments. years ended December 31 (add 000) Total revenues 2017 2016 2015 Mid-America Group $ 1,053,325 $ 1,017,098 $ 926,251 Southeast Group 362,555 321,078 304,472 West Group 2,279,723 2,223,515 2,062,968 Total Building Materials Business 3,695,603 3,561,691 3,293,691 Magnesia Specialties 269,991 257,058 245,879 Total $ 3,965,594 $ 3,818,749 $ 3,539,570 years ended December 31 (add 000) Net sales 2017 2016 2015 Mid-America Group $ 982,109 $ 945,123 $ 851,854 Southeast Group 348,409 304,451 285,302 West Group 2,142,839 2,089,192 1,903,452 Total Building Materials Business 3,473,357 3,338,766 3,040,608 Magnesia Specialties 248,071 238,001 227,508 Total $ 3,721,428 $ 3,576,767 $ 3,268,116 Gross profit (loss) Mid-America Group $ 335,394 $ 306,560 $ 257,002 Southeast Group 74,642 57,286 34,359 West Group 465,595 466,790 360,667 Total Building Materials Business 875,631 830,636 652,028 Magnesia Specialties 89,399 89,603 79,057 Corporate 6,910 (8,501 ) (4,165 ) Total $ 971,940 $ 911,738 $ 726,920 Selling, general and administrative expenses Mid-America Group $ 53,937 $ 52,712 $ 52,227 Southeast Group 17,144 17,245 18,353 West Group 102,650 95,631 92,988 Total Building Materials Business 173,731 165,588 163,568 Magnesia Specialties 9,537 9,617 9,408 Corporate 78,860 66,401 37,778 Total $ 262,128 $ 241,606 $ 210,754 Earnings (Loss) from operations Mid-America Group $ 284,789 $ 258,422 $ 207,619 Southeast Group 61,238 41,653 16,712 West Group 360,544 379,417 256,042 Total Building Materials Business 706,571 679,492 480,373 Magnesia Specialties 79,431 79,306 69,301 Corporate (85,621 ) (81,532 ) (55,507 ) Total $ 700,381 $ 677,266 $ 494,167 as of December 31 (add 000) Assets employed 2017 2016 2015 Mid-America Group $ 1,532,867 $ 1,406,526 $ 1,304,574 Southeast Group 616,344 594,967 583,369 West Group 5,014,231 4,904,018 4,561,432 Total Building Materials Business 7,163,442 6,905,511 6,449,375 Magnesia Specialties 152,257 150,969 147,795 Corporate 1,676,812 244,425 360,441 Total $ 8,992,511 $ 7,300,905 $ 6,957,611 years ended December 31 (add 000) Depreciation, depletion and amortization 2017 2016 2015 Mid-America Group $ 69,691 $ 64,295 $ 61,693 Southeast Group 30,780 30,590 31,644 West Group 169,853 164,653 147,619 Total Building Materials Business 270,324 259,538 240,956 Magnesia Specialties 10,070 10,354 9,992 Corporate 16,768 15,361 12,639 Total $ 297,162 $ 285,253 $ 263,587 Total property additions Mid-America Group $ 139,505 $ 152,014 $ 77,640 Southeast Group 34,636 30,588 12,155 West Group 240,793 338,795 244,844 Total Building Materials Business 414,934 521,397 334,639 Magnesia Specialties 11,129 8,944 8,916 Corporate 12,558 10,430 20,561 Total $ 438,621 $ 540,771 $ 364,116 Property additions through acquisitions Mid-America Group $ 60 $ 1,524 $ 4,385 Southeast Group — — — West Group 2,420 132,112 35,965 Total Building Materials Business 2,480 133,636 40,350 Magnesia Specialties — — — Corporate — — — Total $ 2,480 $ 133,636 $ 40,350 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 are reported within in the West Group. The following tables, which are reconciled to consolidated amounts, provide total revenues, net sales and gross profit by line of business: Building Materials (further divided by product line) and Magnesia Specialties. Interproduct revenues and interproduct sales represent sales from the aggregates product line to the ready mixed concrete and asphalt and paving product lines and sales from the cement product line to the ready mixed concrete product line. years ended December 31 (add 000) Total revenues 2017 2016 2015 Aggregates $ 2,341,540 $ 2,267,574 $ 2,120,245 Cement 384,112 375,814 475,725 Ready Mixed Concrete 936,979 903,803 657,831 Asphalt and Paving 1 296,956 261,612 229,561 Less: Interproduct revenues 1 (263,984 ) (247,112 ) (189,671 ) Total Building Materials Business 3,695,603 3,561,691 3,293,691 Magnesia Specialties 269,991 257,058 245,879 Total $ 3,965,594 $ 3,818,749 $ 3,539,570 Net sales Aggregates $ 2,137,225 $ 2,060,876 $ 1,896,143 Cement 371,525 364,445 455,382 Ready Mixed Concrete 936,062 902,635 656,531 Asphalt and Paving 1 292,529 257,922 222,223 Less: Interproduct sales 1 (263,984 ) (247,112 ) (189,671 ) Total Building Materials Business 3,473,357 3,338,766 3,040,608 Magnesia Specialties 248,071 238,001 227,508 Total $ 3,721,428 $ 3,576,767 $ 3,268,116 1 Gross profit (loss) Aggregates $ 601,968 $ 558,318 $ 470,688 Cement 117,313 120,201 103,813 Ready Mixed Concrete 91,670 99,042 42,110 Asphalt and Paving 64,680 53,075 35,417 Total Building Materials Business 875,631 830,636 652,028 Magnesia Specialties 89,399 89,603 79,057 Corporate 6,910 (8,501 ) (4,165 ) Total $ 971,940 $ 911,738 $ 726,920 Domestic and foreign total revenues are as follows: years ended December 31 (add 000) 2017 2016 2015 Domestic $ 3,901,323 $ 3,761,651 $ 3,493,462 Foreign 64,271 57,098 46,108 Total $ 3,965,594 $ 3,818,749 $ 3,539,570

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Note P: Supplemental Cash Flow Information The components of the change in other assets and liabilities, net, are as follows: years ended December 31 (add 000) 2017 2016 2015 Other current and noncurrent assets $ (19,424 ) $ 9,171 $ (3,631 ) Accrued salaries, benefits and payroll taxes 136 16,942 (4,854 ) Accrued insurance and other taxes 4,866 (2,688 ) 4,425 Accrued income taxes (11,044 ) (12,523 ) (4,364 ) Accrued pension, postretirement and postemployment benefits 1,980 (15,955 ) (18,153 ) Other current and noncurrent liabilities 38,105 (6,053 ) (3,014 ) Change in other assets and liabilities, net $ 14,619 $ (11,106 ) $ (29,591 ) Noncash investing and financing activities are as follows: years ended December 31 (add 000) 2017 2016 2015 Accrued liabilities for purchases of property, plant and equipment $ 61,644 $ 38,566 $ 22,285 Acquisition of assets through capital lease $ 811 $ 1,399 $ 1,445 Acquisition of assets through asset exchange $ 2,476 $ - $ 5,000 Sale of asset to settle liability $ 900 $ - $ - Supplemental disclosures of cash flow information are as follows: years ended December 31 (add 000) 2017 2016 2015 Cash paid for interest $ 78,902 $ 73,664 $ 71,011 Cash paid for income taxes $ 155,771 $ 124,342 $ 46,774

Other Operating Expenses and (I

Other Operating Expenses and (Income), Net	12 Months Ended
	Dec. 31, 2017
Other Income And Expenses [Abstract]
Other Operating Expenses and (Income), Net	Note Q: Other Operating Expenses and (Income), Net Other operating expenses and income, net, are comprised generally of gains and losses on the sale of assets; gains and losses related to certain customer accounts receivable; rental, royalty and services income; accretion expense, depreciation expense and gains and losses related to asset retirement obligations. These net amounts represented an expense of $793,000 in 2017, income of $8,043,000 in 2016 and an expense of $15,653,000 in 2015. The 2017 amount primarily reflects $19,366,000 of gains on the sale of assets, offset by $12,668,000 of nonrecurring repair costs related to certain of the Company’s leased railcars and approximately $10,813,000 of executive retirement expense. The net expense for 2015 reflects the net impact of the divestitures of the California cement operations and the San Antonio asphalt operations.

SCHEDULE II - Valuation and Qua

SCHEDULE II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2017
Valuation And Qualifying Accounts [Abstract]
SCHEDULE II - Valuation and Qualifying Accounts	SCHEDULE II — MARTIN MARIETTA MATERIALS, INC. AND CONSOLIDATED SUBSIDIARIES Col A Col B Col C Col D Col E Additions Description Balance at beginning of period (1) Charged to costs and expenses (2) Charged to other accounts- describe Deductions-describe Balance at end of period (Amounts in Thousands) Year ended December 31, 2017 Allowance for doubtful accounts $ 6,266 $ - $ - $ 3,876 (a) $ 2,390 Allowance for uncollectible notes receivable 437 - - 210 (a) 227 Inventory valuation allowance 134,862 9,099 0 0 143,961 Year ended December 31, 2016 Allowance for doubtful accounts $ 6,940 $ - $ - $ 674 (a) $ 6,266 Allowance for uncollectible notes receivable 585 - - 148 (a) 437 Inventory valuation allowance 130,584 4,160 118 (b) - 134,862 Year ended December 31, 2015 Allowance for doubtful accounts $ 4,077 $ 2,863 $ - $ - $ 6,940 Allowance for uncollectible notes receivable 1,486 0 - 901 (a) 585 Inventory valuation allowance 119,189 13,365 1,400 (b) 3,370 (c) 130,584 (a) Write off of uncollectible accounts and change in estimates. (b) Application of reserve policy to acquired inventories. (c) Divestitures.

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
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 282 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 markets where the Company has a leading aggregates position. Specifically, the Company has two cement plants in Texas, five cement distribution facilities and 152 ready mixed concrete and asphalt plants in Texas, Colorado, Louisiana and Arkansas. 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. As of December 31, 2017, the Building Materials business contains the following reportable segments: Mid-America Group, Southeast Group and West Group. The Mid-America Group operates in Indiana, Iowa, northern Kansas, Kentucky, Maryland, Minnesota, Missouri, eastern Nebraska, North Carolina, Ohio, South Carolina, Virginia, Washington and West Virginia. The Southeast Group has operations in Alabama, Florida, Georgia, Tennessee, Nova Scotia and the Bahamas. The West Group operates in Arkansas, Colorado, southern Kansas, Louisiana, western Nebraska, Nevada, Oklahoma, Texas, Utah and Wyoming. The following states accounted for 74% of the Building Materials business’ 2017 net sales: Texas, Colorado, North Carolina, Iowa and Georgia. The Company also operates a Magnesia Specialties business, which produces magnesia-based chemical products used in industrial, agricultural and environmental applications, and dolomitic lime sold primarily to customers in the steel and mining industries. Magnesia Specialties’ production facilities are located in Ohio and Michigan, and products are shipped to customers worldwide.
Use of Estimates	Use of Estimates. The preparation of the Company’s consolidated financial statements in conformity with accounting principles generally accepted in the United States (U.S. GAAP) requires management to make certain estimates and assumptions about future events. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of revenues and expenses. Such estimates include the valuation of accounts receivable, inventories, goodwill, intangible assets and other long-lived assets and assumptions used in the calculation of income tax (benefit) expense, retirement and other postemployment benefits, and the allocation of the purchase price to the fair values of assets acquired and liabilities assumed as part of business combinations. These estimates and assumptions are based on management’s judgment. Management evaluates estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, and adjusts such estimates and assumptions when facts and circumstances dictate. Changes in credit, equity and energy markets and changes in construction activity increase the uncertainty inherent in certain estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from estimates. Changes in estimates, including those resulting from continuing changes in the economic environment, are reflected in the consolidated financial statements for the period in which the change in estimate occurs.
Basis of Consolidation	Basis of Consolidation . The consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries. Partially-owned affiliates are either consolidated or accounted for at cost or as equity investments, depending on the level of ownership interest or the Company’s ability to exercise control over the affiliates’ operations. Intercompany balances and transactions have been eliminated in consolidation.
Revenue Recognition	Revenue Recognition . Total revenues include sales of materials and services provided to customers, net of discounts or allowances, if any, and include freight and delivery costs billed to customers. Revenues for product sales are recognized when risks associated with ownership have passed to unaffiliated customers. Typically, this occurs when finished products are shipped. Revenues derived from the paving business are recognized using the percentage-of-completion method under the revenue-cost approach. Under the revenue-cost approach, recognized contract revenue equals the total estimated contract revenue multiplied by the percentage of completion. Recognized costs equal the total estimated contract cost multiplied by the percentage of completion. The percentage of completion is determined by costs incurred to date as a percentage of total costs estimated for the project.
Freight and Delivery Costs	Freight and Delivery Costs . Freight and delivery costs represent pass-through transportation costs incurred and paid by the Company to third-party carriers to deliver products to customers. These costs are then billed to the customers.
Cash and Cash Equivalents	Cash and Cash Equivalents . Cash equivalents are comprised of highly-liquid instruments with original maturities of three months or less from the date of purchase. The Company manages its cash and cash equivalents to ensure short-term operating cash needs are met and excess funds are managed efficiently. When operating cash is not sufficient to meet current needs, the Company borrows money under its existing credit facilities. The Company utilizes excess cash to either pay down credit facility borrowings or invest in money market funds, money market demand deposit accounts or offshore time deposit accounts. Money market demand deposits and offshore time deposit accounts are exposed to bank solvency risk.
Customer Receivables	Customer Receivables. Customer receivables are stated at cost. The Company does not typically charge interest on customer accounts receivables. The Company records an allowance for doubtful accounts, which includes a provision for probable losses based on historical write offs and a specific reserve for accounts deemed at risk. The Company writes off customer receivables as bad debt expense when it becomes probable based upon customer facts and circumstances that such amounts will not be collected.
Inventories Valuation	Inventories Valuation . Inventories are stated at the lower of cost or net realizable value. Costs for finished products and in process inventories are determined by the first-in, first-out method. Carrying value for expendable parts and supplies are determined by the weighted-average cost method. The Company records an allowance for finished product inventories based on an analysis of inventory on hand in excess of historical sales for a twelve-month or five year average period and future demand. The Company also establishes an allowance for expendable parts over five years old and supplies over one year old. Post-production stripping costs, which represent costs of removing overburden and waste materials to access mineral deposits, are a component of inventory production costs and recognized in cost of sales in the same period as the revenue from the sale of the inventory.
Property, Plant and Equipment	Property, Plant and Equipment . Property, plant and equipment are stated at cost. The estimated service lives for property, plant and equipment are as follows: Class of Assets Range of Service Lives Buildings 5 to 20 years Machinery & Equipment 2 to 20 years Land Improvements 5 to 60 years The Company begins capitalizing quarry development costs at a point when reserves are determined to be proven or probable, economically mineable and when demand supports investment in the market. Capitalization of these costs ceases when production commences. Capitalized quarry development costs are classified as land improvements and depreciated over the life of the reserves. The Company reviews relevant facts and circumstances to determine whether to capitalize or expense pre-production stripping costs when additional pits are developed at an existing quarry. If the additional pit operates in a separate and distinct area of the quarry, these costs are capitalized as quarry development costs and depreciated over the life of the uncovered reserves. Additionally, a separate asset retirement obligation is created for additional pits when the liability is incurred. Once a pit enters the production phase, all post-production stripping costs are charged to inventory production costs as incurred. Mineral reserves and mineral interests acquired in connection with a business combination are valued using an income approach over the life of the reserves. Depreciation is computed based on estimated service lives, principally using the straight-line method. Depletion of mineral reserves is calculated based on proven and probable reserves using the units-of-production method on a quarry-by-quarry basis. Property, plant and equipment are reviewed for impairment whenever facts and circumstances indicate that the carrying amount of an asset group may not be recoverable. An impairment loss is recognized if expected future undiscounted cash flows over the estimated remaining service life of the related asset are less than the asset’s carrying value.
Repair and Maintenance Costs	Repair and Maintenance Costs. Repair and maintenance costs that do not substantially extend the life of the Company’s plant and equipment are expensed as incurred.
Goodwill and Intangible Assets	Goodwill and Intangible Assets. Goodwill represents the excess purchase price paid for acquired businesses over the estimated fair value of identifiable assets and liabilities. Other intangibles represent amounts assigned principally to contractual agreements and are amortized ratably over periods based on related contractual terms. The Company’s reporting units, which represent the level at which goodwill is tested for impairment, are based on the geographic segments of the Building Materials business. Goodwill is assigned to the respective reporting unit(s) based on the location of acquisitions at the time of consummation. Goodwill is tested for impairment by comparing the reporting unit’s fair value to its carrying value, which represents Step 1 of a two-step approach. However, prior to Step 1, the Company may perform an optional qualitative assessment and evaluate macroeconomic conditions, industry and market conditions, cost factors, overall financial performance and other business or reporting unit-specific events. If the Company concludes it is more-likely-than-not (i.e., a likelihood of more than 50%) that a reporting unit’s fair value is higher than its carrying value, the Company does not perform any further goodwill impairment testing for that reporting unit. Otherwise, it proceeds to Step 1 of its goodwill impairment analysis. The Company may bypass the qualitative assessment for any reporting unit in any period and proceed directly with the quantitative calculation in Step 1. If the reporting unit’s fair value exceeds its carrying value, no further calculation is necessary. A reporting unit with a carrying value in excess of its fair value constitutes a Step 1 failure and may lead to an impairment charge. The carrying values of goodwill and other indefinite-lived intangible assets are reviewed annually, as of October 1, for impairment. An interim review is performed between annual tests if facts and circumstances indicate potential impairment. The carrying value of other amortizable intangibles is reviewed if facts and circumstances indicate potential impairment. If a review indicates the carrying value is impaired, a charge is recorded.
Retirement Plans and Postretirement Benefits	Retirement Plans and Postretirement Benefits. The Company sponsors defined benefit retirement plans and also provides other postretirement benefits. The Company recognizes the funded status, defined as the difference between the fair value of plan assets and the benefit obligation, of its pension plans and other postretirement benefits as an asset or liability on the consolidated balance sheets. Actuarial gains or losses that arise during the year are not recognized as net periodic benefit cost in the same year, but rather are recognized as a component of accumulated other comprehensive earnings or loss. Those amounts are amortized over the participants’ average remaining service period and recognized as a component of net periodic benefit cost. The amount amortized is determined using a corridor approach and represents the excess over 10% of the greater of the projected benefit obligation or pension plan assets.
Stock-Based Compensation	Stock-Based Compensation. The Company has stock-based compensation plans for employees and its Board of Directors. The Company recognizes all forms of stock-based awards that vest, including stock options, as compensation expense. The compensation expense is the fair value of the awards at the measurement date and is recognized over the requisite service period. The fair value of restricted stock awards, incentive compensation stock awards and Board of Directors’ fees paid in the form of common stock are based on the closing price of the Company’s common stock on the awards’ respective grant dates. The fair value of performance stock awards is determined by a Monte Carlo simulation methodology. In 2017 and 2016, the Company did not issue any stock options. For stock options issued prior to 2016, the Company used the accelerated expense recognition method. The accelerated recognition method requires stock options that vest ratably to be divided into tranches. The expense for each tranche is allocated to its particular vesting period. The Company uses the lattice valuation model to determine the fair value of stock option awards. The lattice valuation model takes into account employees’ exercise patterns based on changes in the Company’s stock price and other variables. The period of time for which options are expected to be outstanding is a derived output of the lattice valuation model and includes the following considerations: vesting period of the award, expected volatility of the underlying stock and employees’ ages. Key assumptions used in determining the fair value of the stock options awarded in 2015 were: Risk-free interest rate 2.20% Dividend yield 1.20% Volatility factor 36.10% Expected term 8.5 years Based on these assumptions, the weighted-average fair value of each stock option granted in 2015 was $57.71. The risk-free interest rate reflects the interest rate on zero-coupon U.S. government bonds, available at the time each option was granted, having a remaining life approximately equal to the option’s expected life. The dividend yield represents the dividend rate expected to be paid over the option’s expected life. The Company’s volatility factor measures the amount by which its stock price is expected to fluctuate during the expected life of the option and is based on historical stock price changes. Forfeitures are required to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company estimates forfeitures and will ultimately recognize compensation cost only for those stock-based awards that vest.
Environmental Matters	Environmental Matters. The Company records a liability for an asset retirement obligation at fair value in the period in which it is incurred. The asset retirement obligation is recorded at the acquisition date of a long-lived tangible asset if the fair value can be reasonably estimated. A corresponding amount is capitalized as part of the asset’s carrying amount. The fair value is affected by management’s assumptions regarding the scope of the work required, inflation rates and quarry closure dates. Further, the Company records an accrual for other environmental remediation liabilities in the period in which it is probable that a liability has been incurred and the appropriate amounts can be estimated reasonably. Such accruals are adjusted as further information develops or circumstances change. Generally, these costs are not discounted to their present value or offset for potential insurance or other claims or potential gains from future alternative uses for a site.
Income Taxes	Income Taxes . Deferred income taxes, net, on the consolidated balance sheets reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, net of valuation allowances. The effect on deferred income tax assets and liabilities attributable to changes in enacted tax rates are charged or credited to income tax expense or benefit in the period of enactment.
Uncertain Tax Positions	Uncertain Tax Positions. The Company recognizes a tax benefit when it is more-likely-than-not, based on the technical merits, that a tax position would be sustained upon examination by a taxing authority. The amount to be recognized is measured as the largest amount of tax benefit that is greater than 50% likely of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. The Company’s unrecognized tax benefits are recorded in other liabilities on the consolidated balance sheets or as an offset to the deferred tax asset for tax carryforwards where available. 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.
Sales Taxes	Sales Taxes. Sales taxes collected from customers are recorded as liabilities until remitted to taxing authorities and therefore are not reflected in the consolidated statements of earnings.
Start-Up Costs	Start-Up Costs. Noncapital start-up costs for new facilities and products are charged to operations as incurred.
Warranties	Warranties. The Company’s construction contracts contain warranty provisions covering defects in materials, design or workmanship that generally run from nine months to one year after project completion. Due to the nature of its projects, including contract owner inspections of the work both during construction and prior to acceptance, the Company has not experienced material warranty costs for these short-term warranties and therefore does not believe an accrual for these costs is necessary. The ready mixed concrete product line carries a longer warranty period, 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 projects. These costs were not material to the Company’s consolidated results of operations for the years ended December 31, 2017, 2016 and 2015.
Consolidated Comprehensive Earnings and Accumulated Other Comprehensive Loss	Consolidated Comprehensive Earnings and Accumulated Other Comprehensive Loss . Consolidated comprehensive earnings for the Company consist of consolidated net earnings, 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 comprehensive earnings. Accumulated other comprehensive loss consists of unrecognized gains and losses related to the funded status of the pension and postretirement benefit plans, foreign currency translation and the unamortized value of terminated forward starting interest rate swap agreements, and is presented on the Company’s consolidated balance sheets. The components of the changes in accumulated other comprehensive loss and related cumulative noncurrent deferred tax assets are as follows: Pension and Postretirement Benefit Plans Foreign Currency Unamortized Value of Terminated Forward Starting Interest Rate Swap Total years ended December 31 (add 000) 2017 Accumulated other comprehensive loss at beginning of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Other comprehensive (loss) earnings before reclassifications, net of tax (8,062 ) 1,140 — (6,922 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 7,633 — 872 8,505 Other comprehensive (loss) earnings, net of tax (429 ) 1,140 872 1,583 Accumulated other comprehensive loss at end of period $ (128,802 ) $ (22 ) $ (280 ) $ (129,104 ) Cumulative noncurrent deferred tax assets at end of period $ 79,938 $ — $ 178 $ 80,116 2016 Accumulated other comprehensive loss at beginning of period $ (103,380 ) $ (264 ) $ (1,978 ) $ (105,622 ) Other comprehensive loss before reclassifications, net of tax (31,678 ) (898 ) — (32,576 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 6,685 — 826 7,511 Other comprehensive (loss) earnings, net of tax (24,993 ) (898 ) 826 (25,065 ) Accumulated other comprehensive loss at end of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Cumulative noncurrent deferred tax assets at end of period $ 82,044 $ — $ 749 $ 82,793 2015 Accumulated other comprehensive (loss) earnings at beginning of period $ (106,688 ) $ 3,278 $ (2,749 ) $ (106,159 ) Other comprehensive loss before reclassifications, net of tax (7,116 ) (3,542 ) — (10,658 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 10,424 — 771 11,195 Other comprehensive earnings (loss), net of tax 3,308 (3,542 ) 771 537 Accumulated other comprehensive loss at end of period $ (103,380 ) $ (264 ) $ (1,978 ) $ (105,622 ) Cumulative noncurrent deferred tax assets at end of period $ 66,467 $ — $ 1,290 $ 67,757 Reclassifications out of accumulated other comprehensive loss are as follows: years ended December 31 (add 000) 2017 2016 2015 Affected line items in the consolidated statements of earnings Pension and postretirement benefit plans Special plan termination benefits $ - $ 764 $ 2,085 Settlement charge 21 115 — Amortization of: Prior service credit (1,430 ) (1,609 ) (1,880 ) Actuarial loss 13,774 11,575 16,850 12,365 10,845 17,055 Other nonoperating (income) and expenses, net Tax effect (4,732 ) (4,160 ) (6,631 ) Income tax (benefit) expense Total $ 7,633 $ 6,685 $ 10,424 Unamortized value of terminated forward starting interest rate swap Additional interest expense $ 1,443 $ 1,367 $ 1,280 Interest expense Tax effect (571 ) (541 ) (509 ) Income tax (benefit) expense Total $ 872 $ 826 $ 771
Earnings Per Common Share	Earnings Per Common Share . The Company computes earnings per share (EPS) pursuant to the two-class method. The two-class method determines EPS for each class of common stock and participating securities according to dividends or dividend equivalents and their respective participation rights in undistributed earnings. The Company pays nonforfeitable dividend equivalents during the vesting period on its restricted stock awards and incentive stock awards made prior to 2016, which results in these being considered participating securities. The numerator for basic and diluted earnings per common share is net earnings attributable to Martin Marietta, reduced by dividends and undistributed earnings attributable to the Company’s unvested restricted stock awards and incentive stock awards issued prior to 2016. 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 issued to employees and nonemployee members of the Company’s Board of Directors under certain stock-based compensation arrangements if the conversion is dilutive. The following table reconciles the numerator and denominator for basic and diluted earnings per common share: years ended December 31 (add 000) 2017 2016 2015 Net earnings attributable to Martin Marietta $ 713,342 $ 425,386 $ 288,792 Less: Distributed and undistributed earnings attributable to unvested awards 2,029 1,775 1,252 Basic and diluted net earnings attributable to common shareholders attributable to Martin Marietta $ 711,313 $ 423,611 $ 287,540 Basic weighted-average common shares outstanding 62,932 63,610 66,770 Effect of dilutive employee and director awards 285 251 250 Diluted weighted-average common shares outstanding 63,217 63,861 67,020
New Accounting Pronouncements	New Accounting Pronouncements . Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In March 2017, the Financial Accounting Standards Board (FASB) issued an accounting standards update (ASU), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost , Stock Compensation The FASB issued ASU Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting
Pending Accounting Pronouncements	Pending Accounting Pronouncements. Revenue Recognition Standard The FASB issued ASU Revenue From Contracts with Customers Lease Standard In February 2016, the FASB issued a new accounting standard, Accounting Codification Standard 842 – Leases, In January 2018, the FASB issued ASU Land Easement Practical Expedient for Transition to Topic 842

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Estimated Service Lives for Property Plant and Equipment	The estimated service lives for property, plant and equipment are as follows: Class of Assets Range of Service Lives Buildings 5 to 20 years Machinery & Equipment 2 to 20 years Land Improvements 5 to 60 years
Summary of Key Assumptions Used in Determining Fair Value of Stock Options Awarded	Key assumptions used in determining the fair value of the stock options awarded in 2015 were: Risk-free interest rate 2.20% Dividend yield 1.20% Volatility factor 36.10% Expected term 8.5 years
Components of Changes in Accumulated Other Comprehensive Loss and Related Cumulative Noncurrent Deferred Tax Assets	The components of the changes in accumulated other comprehensive loss and related cumulative noncurrent deferred tax assets are as follows: Pension and Postretirement Benefit Plans Foreign Currency Unamortized Value of Terminated Forward Starting Interest Rate Swap Total years ended December 31 (add 000) 2017 Accumulated other comprehensive loss at beginning of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Other comprehensive (loss) earnings before reclassifications, net of tax (8,062 ) 1,140 — (6,922 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 7,633 — 872 8,505 Other comprehensive (loss) earnings, net of tax (429 ) 1,140 872 1,583 Accumulated other comprehensive loss at end of period $ (128,802 ) $ (22 ) $ (280 ) $ (129,104 ) Cumulative noncurrent deferred tax assets at end of period $ 79,938 $ — $ 178 $ 80,116 2016 Accumulated other comprehensive loss at beginning of period $ (103,380 ) $ (264 ) $ (1,978 ) $ (105,622 ) Other comprehensive loss before reclassifications, net of tax (31,678 ) (898 ) — (32,576 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 6,685 — 826 7,511 Other comprehensive (loss) earnings, net of tax (24,993 ) (898 ) 826 (25,065 ) Accumulated other comprehensive loss at end of period $ (128,373 ) $ (1,162 ) $ (1,152 ) $ (130,687 ) Cumulative noncurrent deferred tax assets at end of period $ 82,044 $ — $ 749 $ 82,793 2015 Accumulated other comprehensive (loss) earnings at beginning of period $ (106,688 ) $ 3,278 $ (2,749 ) $ (106,159 ) Other comprehensive loss before reclassifications, net of tax (7,116 ) (3,542 ) — (10,658 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 10,424 — 771 11,195 Other comprehensive earnings (loss), net of tax 3,308 (3,542 ) 771 537 Accumulated other comprehensive loss at end of period $ (103,380 ) $ (264 ) $ (1,978 ) $ (105,622 ) Cumulative noncurrent deferred tax assets at end of period $ 66,467 $ — $ 1,290 $ 67,757
Reclassification Out of Accumulated Other Comprehensive Loss	Reclassifications out of accumulated other comprehensive loss are as follows: years ended December 31 (add 000) 2017 2016 2015 Affected line items in the consolidated statements of earnings Pension and postretirement benefit plans Special plan termination benefits $ - $ 764 $ 2,085 Settlement charge 21 115 — Amortization of: Prior service credit (1,430 ) (1,609 ) (1,880 ) Actuarial loss 13,774 11,575 16,850 12,365 10,845 17,055 Other nonoperating (income) and expenses, net Tax effect (4,732 ) (4,160 ) (6,631 ) Income tax (benefit) expense Total $ 7,633 $ 6,685 $ 10,424 Unamortized value of terminated forward starting interest rate swap Additional interest expense $ 1,443 $ 1,367 $ 1,280 Interest expense Tax effect (571 ) (541 ) (509 ) Income tax (benefit) expense Total $ 872 $ 826 $ 771
Basic and Diluted Earnings Per Common Share	The following table reconciles the numerator and denominator for basic and diluted earnings per common share: years ended December 31 (add 000) 2017 2016 2015 Net earnings attributable to Martin Marietta $ 713,342 $ 425,386 $ 288,792 Less: Distributed and undistributed earnings attributable to unvested awards 2,029 1,775 1,252 Basic and diluted net earnings attributable to common shareholders attributable to Martin Marietta $ 711,313 $ 423,611 $ 287,540 Basic weighted-average common shares outstanding 62,932 63,610 66,770 Effect of dilutive employee and director awards 285 251 250 Diluted weighted-average common shares outstanding 63,217 63,861 67,020

Goodwill and Other Intangible30

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Changes in Goodwill	The following table shows the changes in goodwill by reportable segment and in total. December 31 Mid- America Group Southeast Group West Group Total (add 000) 2017 Balance at beginning of period $ 281,403 $ 50,346 $ 1,827,588 $ 2,159,337 Acquisitions — — 230 230 Purchase price adjustments — — 723 723 Balance at end of period $ 281,403 $ 50,346 $ 1,828,541 $ 2,160,290 2016 Balance at beginning of period $ 281,403 $ 50,346 $ 1,736,486 $ 2,068,235 Acquisitions — — 91,174 91,174 Divestitures — — (72 ) (72 ) Balance at end of period $ 281,403 $ 50,346 $ 1,827,588 $ 2,159,337
Intangible Assets Subject to Amortization	Intangible assets subject to amortization consist of the following: December 31 Gross Amount Accumulated Amortization Net Balance (add 000) 2017 Noncompetition agreements $ 6,274 $ (6,144 ) $ 130 Customer relationships 45,755 (17,351 ) 28,404 Operating permits 458,952 (26,436 ) 432,516 Use rights and other 16,946 (10,377 ) 6,569 Trade names 12,800 (7,947 ) 4,853 Total $ 540,727 $ (68,255 ) $ 472,472 2016 Noncompetition agreements $ 6,274 $ (6,106 ) $ 168 Customer relationships 45,755 (13,636 ) 32,119 Operating permits 455,095 (19,493 ) 435,602 Use rights and other 16,946 (9,239 ) 7,707 Trade names 12,800 (5,681 ) 7,119 Total $ 536,870 $ (54,155 ) $ 482,715
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: December 31 Building Materials Business Magnesia Specialties Total (add 000) 2017 Operating permits $ 6,600 $ — $ 6,600 Use rights 24,432 — 24,432 Trade names 280 2,565 2,845 Total $ 31,312 $ 2,565 $ 33,877 2016 Operating permits $ 6,600 $ — $ 6,600 Use rights 19,152 — 19,152 Trade names 280 2,565 2,845 Total $ 26,032 $ 2,565 $ 28,597
Schedule of Acquired Intangibles	During 2017, the Company acquired $10,270,000 of intangibles, consisting of the following: (add 000, except year data) Amount Weighted-average amortization period Subject to amortization: Operating permits $ 4,990 40 years Not subject to amortization: Use Rights 5,280 N/A Total $ 10,270
Estimated Amortization Expense of Intangible Assets	The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: (add 000) 2018 $ 13,070 2019 12,114 2020 12,078 2021 11,387 2022 9,805 Thereafter 414,018 Total $ 472,472

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Schedule of Accounts Receivable Net	(add 000) 2017 2016 Customer receivables $ 480,073 $ 456,508 Other current receivables 9,557 7,668 489,630 464,176 Less allowances (2,390 ) (6,266 ) Total $ 487,240 $ 457,910

Inventories, Net (Tables)

Inventories, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Inventory Disclosure [Abstract]
Schedule of Inventories Net	December 31 (add 000) 2017 2016 Finished products $ 552,999 $ 479,291 Products in process and raw materials 62,761 61,171 Supplies and expendable parts 128,792 116,024 744,552 656,486 Less allowances (143,961 ) (134,862 ) Total $ 600,591 $ 521,624

Property, Plant and Equipment33

Property, Plant and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Property, Plant and Equipment, Net	December 31 (add 000) 2017 2016 Land and land improvements $ 974,622 $ 915,158 Mineral reserves and interests 1,162,289 1,114,560 Buildings 154,564 151,115 Machinery and equipment 4,006,619 3,766,975 Construction in progress 199,973 167,722 6,498,067 6,115,530 Less accumulated depreciation, depletion and amortization (2,905,254 ) (2,692,135 ) Total $ 3,592,813 $ 3,423,395
Gross Asset Value and Accumulated Amortization for Machinery and Equipment Recorded under Capital Lease	The gross asset value and accumulated amortization for machinery and equipment recorded under capital leases at December 31 were as follows: (add 000) 2017 2016 Machinery and equipment under capital leases $ 23,919 $ 23,117 Less accumulated amortization (11,243 ) (8,077 ) Total $ 12,676 $ 15,040

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Long-Term Debt	December 31 (add 000) 2017 2016 6.60% Senior Notes, due 2018 $ 299,871 $ 299,483 4.25% Senior Notes, due 2024 395,814 395,252 7% Debentures, due 2025 124,180 124,090 3.450% Senior Notes, due 2027 296,628 - 3.500% Senior Notes, due 2027 494,352 - 6.25% Senior Notes, due 2037 228,033 227,975 4.250% Senior Notes, due 2047 591,688 - Floating Rate Senior Notes, due 2019, interest rate of 2.13% at December 31, 2017 298,102 - Floating Rate Senior Notes, due 2020, interest rate of 2.10% at December 31, 2017 298,227 - Floating Rate Senior Notes, due 2017, interest rate of 2.10% at December 31, 2016 - 299,033 Revolving Facility, due 2022, interest rate of 1.86% at December 31, 2016 - 160,000 Trade Receivable Facility, interest rate of 1.34% at December 31, 2016 - 180,000 Other notes 308 356 Total 3,027,203 1,686,189 Less current maturities (299,909 ) (180,036 ) Long-term debt $ 2,727,294 $ 1,506,153
Schedule of Principal Amount, Effective Interest Rate and Maturity Date for Corporation's Senior Notes	Principal Amount (add 000) Effective Interest Rate Maturity Date 6.60% Senior Notes $ 300,000 6.81% April 15, 2018 4.25% Senior Notes $ 400,000 4.25% July 2, 2024 7% Debentures $ 125,000 7.12% December 1, 2025 3.450% Senior Notes $ 300,000 3.47% June 1, 2027 3.500% Senior Notes $ 500,000 3.53% December 15, 2027 6.25% Senior Notes $ 230,000 6.45% May 1, 2037 4.250% Senior Notes $ 600,000 4.27% December 15, 2047 Floating Rate Senior Notes, due 2019 $ 300,000 Three-month LIBOR + 0.50% December 20, 2019 Floating Rate Senior Notes, due 2020 $ 300,000 Three-month LIBOR + 0.65% May 22, 2020
Schedule of Corporation's Long-Term Debt Maturities	The Company’s long-term debt maturities for the five years following December 31, 2017, and thereafter are: (add 000) 2018 $ 299,909 2019 298,157 2020 298,286 2021 65 2022 90 Thereafter 2,130,696 Total $ 3,027,203

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Components of Income Tax (Benefit) Expense	The components of the Company’s income tax (benefit) expense are as follows: years ended December 31 (add 000) 2017 2016 2015 Federal income taxes: Current $ 129,236 $ 97,975 $ 20,627 Deferred (239,304 ) 68,899 85,295 Total federal income tax (benefit) expense (110,068 ) 166,874 105,922 State income taxes: Current 14,843 15,189 18,153 Deferred (882 ) (1,149 ) 930 Total state income taxes 13,961 14,040 19,083 Foreign income taxes: Current 1,175 1,064 99 Deferred 475 (394 ) (241 ) Total foreign income taxes 1,650 670 (142 ) Income tax (benefit) expense $ (94,457 ) $ 181,584 $ 124,863
Summary of Effective Income Tax Rate	The Company’s effective income tax rate varied from the statutory United States income tax rate because of the following tax differences: years ended December 31 2017 2016 2015 Statutory tax rate 35.0 % 35.0 % 35.0 % (Reduction) increase resulting from: Provisional remeasurement of deferred taxes due to 2017 Tax Act (41.7 ) — — Effect of statutory depletion (5.6 ) (5.4 ) (7.8 ) State income taxes, net of federal tax benefit 1.5 1.5 3.0 Domestic production deduction (2.2 ) (2.0 ) (0.1 ) Stock based compensation (1.0 ) (0.1 ) (0.3 ) Other items (1.3 ) 0.9 0.4 Effective income tax rate (15.3%) 29.9 % 30.2 %
Components of Deferred Tax Assets and Liabilities	The principal components of the Company’s deferred tax assets and liabilities are as follows: December 31 Deferred Assets (Liabilities) (add 000) 2017 2016 Deferred tax assets related to: Employee benefits $ 16,059 $ 61,462 Inventories 56,242 71,490 Valuation and other reserves 22,989 38,206 Net operating loss carryforwards 11,780 10,507 Accumulated other comprehensive loss 80,116 82,793 AMT credit carryforward - 2,771 Gross deferred tax assets 187,186 267,229 Valuation allowance on deferred tax assets (10,349 ) (8,521 ) Total net deferred tax assets 176,837 258,708 Deferred tax liabilities related to: Property, plant and equipment (407,400 ) (635,576 ) Goodwill and other intangibles (168,506 ) (268,999 ) Other items, net (11,654 ) (17,152 ) Total deferred tax liabilities (587,560 ) (921,727 ) Deferred income taxes, net $ (410,723 ) $ (663,019 )
Schedule of Unrecognized Tax Benefits Excluding Interest Correlative Effects	The following table summarizes the Company’s unrecognized tax benefits, excluding interest and correlative effects: years ended December 31 (add 000) 2017 2016 2015 Unrecognized tax benefits at beginning of year $ 21,807 $ 18,727 $ 21,107 Gross increases – tax positions in prior years 1,396 2,401 3,079 Gross decreases – tax positions in prior years (672 ) (1,924 ) (3,512 ) Gross increases – tax positions in current year 4,961 4,650 4,978 Gross decreases – tax positions in current year (946 ) (2,047 ) (594 ) Lapse of statute of limitations (4,179 ) - (6,331 ) Unrecognized tax benefits at end of year $ 22,367 $ 21,807 $ 18,727

Retirement Plans, Postretirem36

Retirement Plans, Postretirement and Postemployment Benefits (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Values of Pension Plan Assets by Asset Class and Fair Value Hierarchy Level	The fair values of pension plan assets by asset class and fair value hierarchy level are as follows: December 31 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value (add 000) 2017 Equity securities: Mid-sized to large cap $ — $ 177,497 $ — $ 177,497 Small cap, international and emerging growth funds — 186,272 — 186,272 Debt securities: Core fixed income — 182,225 — 182,225 Real estate — — 46,467 46,467 Hedge funds — — 45,604 45,604 Cash 41 — — 41 Total $ 41 $ 545,994 $ 92,071 $ 638,106 2016 Equity securities: Mid-sized to large cap $ — $ 169,176 $ — $ 169,176 Small cap, international and emerging growth funds — 169,678 — 169,678 Debt securities: Core fixed income — 168,282 — 168,282 Real estate — — 44,890 44,890 Hedge funds — — 44,036 44,036 Cash 145 — — 145 Total $ 145 $ 507,136 $ 88,926 $ 596,207
Schedule of Assumed Health Care Cost Trend Rates	Assumed health care cost trend rates at December 31 are: 2017 2016 Health care cost trend rate assumed for next year 7.0% 7.0% Rate to which the cost trend rate gradually declines 5.0% 5.0% Year the rate reaches the ultimate rate 2022 2021
Schedule of One Percentage-Point Change in Assumed Health Care Cost Trend Rates	A one percentage-point change in assumed health care cost trend rates would have the following effects: One Percentage Point (add 000) Increase (Decrease) Total service and interest cost components $ 41 $ (34 ) Postretirement benefit obligation $ 783 $ (631 )
Pension
Schedule of Components of Net Periodic Benefit Credit Cost	The net periodic retirement benefit cost of defined benefit plans includes the following components: years ended December 31 (add 000) 2017 2016 2015 Service cost $ 26,805 $ 22,167 $ 23,001 Interest cost 36,101 35,879 33,151 Expected return on assets (39,759 ) (37,699 ) (36,385 ) Amortization of: Prior service cost 311 350 422 Actuarial loss 14,138 12,074 17,159 Transition asset (1 ) (1 ) (1 ) Settlement charge 21 124 — Termination benefit charge — 764 2,085 Net periodic benefit cost $ 37,616 $ 33,658 $ 39,432
Schedule of Recognized Comprehensive Earnings	The Company recognized the following amounts in consolidated comprehensive earnings: years ended December 31 (add 000) 2017 2016 2015 Actuarial loss $ 13,343 $ 52,028 $ 9,916 Amortization of: Prior service cost (311 ) (350 ) (422 ) Actuarial loss (14,138 ) (12,074 ) (17,159 ) Transition asset 1 1 1 Special plan termination benefits — (764 ) (2,085 ) Settlement charge (21 ) (124 ) — Net prior service cost — — 2,338 Total $ (1,126 ) $ 38,717 $ (7,411 )
Schedule of Net Periodic Benefit Credit or Cost Not Yet Recognized	Accumulated other comprehensive loss includes the following amounts that have not yet been recognized in net periodic benefit cost: December 31 2017 2016 (add 000) Gross Net of tax Gross Net of tax Prior service cost $ 115 $ 71 $ 425 $ 261 Actuarial loss 217,240 134,066 218,056 133,083 Transition asset (6 ) (4 ) (7 ) (4 ) Total $ 217,349 $ 134,133 $ 218,474 $ 133,340
Schedule of Change in Projected Benefit Obligation	The defined benefit plans’ change in projected benefit obligation is as follows: years ended December 31 (add 000) 2017 2016 Net projected benefit obligation at beginning of year $ 831,849 $ 754,543 Service cost 26,805 22,167 Interest cost 36,101 35,879 Actuarial loss 56,675 49,760 Gross benefits paid (72,095 ) (30,500 ) Net projected benefit obligation at end of year $ 879,335 $ 831,849
Schedule of Change In Plan Assets	The Company’s change in plan assets, funded status and amounts recognized on the Company’s consolidated balance sheets are as follows: years ended December 31 (add 000) 2017 2016 Change in plan assets: Fair value of plan assets at beginning of year $ 596,207 $ 546,512 Actual return on plan assets, net 83,091 35,432 Employer contributions 30,903 44,763 Gross benefits paid (72,095 ) (30,500 ) Fair value of plan assets at end of year $ 638,106 $ 596,207
Schedule of Funded Status	December 31 (add 000) 2017 2016 Funded status of the plan at end of year $ (241,229 ) $ (235,642 ) Accrued benefit cost $ (241,229 ) $ (235,642 )
Schedule of Amounts Recognized on Consolidated Balance Sheets	December 31 (add 000) 2017 2016 Amounts recognized on consolidated balance sheets consist of: Current liability $ (11,092 ) $ (6,223 ) Noncurrent liability (230,137 ) (229,419 ) Net amount recognized at end of year $ (241,229 ) $ (235,642 )
Schedule of Accumulated Benefit Obligations in Excess of Plan Assets	Benefit obligations and fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets are as follows: December 31 (add 000) 2017 2016 Projected benefit obligation $ 879,335 $ 831,849 Accumulated benefit obligation $ 792,912 $ 752,659 Fair value of plan assets $ 638,106 $ 596,207
Schedule of Weighted-Average Assumptions	Weighted-average assumptions used to determine benefit obligations as of December 31 are: 2017 2016 Discount rate 3.76% 4.29% Rate of increase in future compensation levels 4.50% 4.50% Weighted-average assumptions used to determine net periodic benefit cost for years ended December 31 are: 2017 2016 2015 Discount rate 4.29% 4.67% 4.25% Rate of increase in future compensation levels 4.50% 4.50% 4.50% Expected long-term rate of return on assets 6.75% 7.00% 7.00%
Schedule of Target Assets Allocation	The target allocation for 2017 and the actual pension plan asset allocation by asset class are as follows: Percentage of Plan Assets 2017 December 31 Asset Class Target Allocation 2017 2016 Equity securities 54% 57% 57% Debt securities 30% 29% 28% Hedge funds 8% 7% 7% Real estate 8% 7% 8% Total 100% 100% 100%
Change in Fair Value of Pension Plan Assets	The change in the fair value of pension plan assets valued using significant unobservable inputs (Level 3) is as follows: years ended December 31 Real Estate Hedge Funds (add 000) 2017 Balance at beginning of year $ 44,890 $ 44,036 Purchases, sales, settlements, net (83 ) — Actual return on plan assets held at period end 1,660 1,568 Balance at end of year $ 46,467 $ 45,604 2016 Balance at beginning of year $ 23,242 $ 39,219 Purchases, sales, settlements, net 18,579 3,100 Actual return on plan assets held at period end 3,069 1,717 Balance at end of year $ 44,890 $ 44,036
Schedule of Expected Benefit Payments	The expected benefit payments to be paid from plan assets for each of the next five years and the five-year period thereafter are as follows: (add 000) 2018 $ 43,090 2019 $ 40,894 2020 $ 43,143 2021 $ 44,568 2022 $ 46,359 Years 2023 - 2027 $ 261,475
Postretirement Benefits
Schedule of Components of Net Periodic Benefit Credit Cost	The net periodic postretirement benefit credit cost for postretirement plans includes the following components: years ended December 31 (add 000) 2017 2016 2015 Service cost $ 80 $ 85 $ 137 Interest cost 727 863 928 Amortization of: Prior service credit (1,741 ) (1,959 ) (2,302 ) Actuarial gain (364 ) (499 ) (309 ) Settlement credit — (9 ) — Total net periodic benefit credit $ (1,298 ) $ (1,519 ) $ (1,546 )
Schedule of Recognized Comprehensive Earnings	The Company recognized the following amounts in consolidated comprehensive earnings: years ended December 31 (add 000) 2017 2016 2015 Actuarial loss (gain) $ 1,236 $ 686 $ (626 ) Net prior service credit (3,902 ) (1,326 ) — Settlement credit — 9 — Amortization of: Prior service credit 1,741 1,959 2,302 Actuarial gain 364 499 309 Total $ (561 ) $ 1,827 $ 1,985
Schedule of Net Periodic Benefit Credit or Cost Not Yet Recognized	Accumulated other comprehensive loss includes the following amounts that have not yet been recognized in net periodic benefit credit or cost: December 31 2017 2016 (add 000) Gross Net of tax Gross Net of tax Prior service credit $ (6,314 ) $ (3,899 ) $ (4,153 ) $ (2,551 ) Actuarial gain (2,256 ) (1,393 ) (3,857 ) (2,369 ) Total $ (8,570 ) $ (5,292 ) $ (8,010 ) $ (4,920 )
Schedule of Change in Projected Benefit Obligation	The postretirement health care plans’ change in benefit obligation is as follows: years ended December 31 (add 000) 2017 2016 Change in benefit obligation: Net benefit obligation at beginning of year $ 20,591 $ 23,408 Service cost 80 85 Interest cost 727 863 Participants’ contributions 3,421 2,616 Actuarial loss 1,236 688 Gross benefits paid (6,806 ) (5,743 ) Plan amendments (3,902 ) (1,326 ) Net benefit obligation at end of year $ 15,347 $ 20,591
Schedule of Change In Plan Assets	The Company’s change in plan assets, funded status and amounts recognized on the Company’s consolidated balance sheets are as follows: years ended December 31 (add 000) 2017 2016 Fair value of plan assets at beginning of year $ — $ — Employer contributions 3,385 3,127 Participants’ contributions 3,421 2,616 Gross benefits paid (6,806 ) (5,743 ) Fair value of plan assets at end of year $ — $ —
Schedule of Funded Status	December 31 (add 000) 2017 2016 Funded status of the plan at end of year $ (15,347 ) $ (20,591 ) Accrued benefit cost $ (15,347 ) $ (20,591 )
Schedule of Amounts Recognized on Consolidated Balance Sheets	December 31 (add 000) 2017 2016 Amounts recognized on consolidated balance sheets consist of: Current liability $ (2,560 ) $ (3,070 ) Noncurrent liability (12,787 ) (17,521 ) Net amount recognized at end of year $ (15,347 ) $ (20,591 )
Schedule of Weighted-Average Assumptions	Weighted-average assumptions used to determine the postretirement benefit obligations as of December 31 are: 2017 2016 Discount rate 3.47 % 3.78 % Weighted-average assumptions used to determine net postretirement benefit cost for the years ended December 31 are: 2017 2016 2015 Discount rate 3.78 % 4.25 % 3.83 %
Schedule of Expected Benefit Payments	The total expected benefit payments to be paid by the Company, net of participant contributions, for each of the next five years and the five-year period thereafter are as follows: (add 000) 2018 $ 2,560 2019 $ 1,610 2020 $ 1,557 2021 $ 1,470 2022 $ 1,393 Years 2023 - 2027 $ 4,888

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary Information for Restricted Stock Awards and Incentive Compensation Stock Awards	The following table summarizes information for restricted stock awards and incentive compensation stock awards for 2017: Restricted Stock - Service Based Restricted Stock - Performance Based Incentive Compensation Stock Number of Awards Weighted- Average Grant-Date Fair Value Number of Awards Weighted- Average Grant-Date Fair Value Number of Awards Weighted- Average Grant-Date Fair Value January 1, 2017 307,317 $ 125.36 111,317 $ 122.22 40,549 $ 114.44 Awarded 80,181 $ 213.76 47,997 $ 207.73 19,981 $ 208.68 Distributed (68,828 ) $ 121.40 (17,692 ) $ 129.14 (21,784 ) $ 108.44 Forfeited (3,830 ) $ 156.40 (1,623 ) $ 150.38 (236 ) $ 124.41 December 31, 2017 314,840 $ 151.84 139,999 $ 150.34 38,510 $ 166.67
Summary Information for Stock Options	The following table includes summary information for stock options as of December 31, 2017: Number of Options Weighted- Average Exercise Price Weighted-Average Remaining Contractual Life (years) Outstanding at January 1, 2017 406,891 $ 93.27 Exercised (104,093 ) $ 98.68 Terminated (840 ) $ 80.52 Outstanding at December 31, 2017 301,958 $ 91.44 3.6 Exercisable at December 31, 2017 261,380 $ 83.37 3.1
Schedule of Stock-Based Compensation Expense	The following table summarizes stock-based compensation expense for the years ended December 31, 2017, 2016 and 2015, unrecognized compensation cost for nonvested awards at December 31, 2017 and the weighted-average period over which unrecognized compensation cost will be recognized: (add 000, except year data) Stock Options Restricted Stock Incentive Compensation Stock Directors’ Awards Total Stock-based compensation expense recognized for years ended December 31: 2017 $ 684 $ 28,657 $ 661 $ 458 $ 30,460 2016 $ 1,646 $ 17,747 $ 442 $ 646 20,481 2015 $ 2,679 $ 9,809 $ 376 $ 725 13,589 Unrecognized compensation cost at December 31, 2017: $ 292 $ 24,116 $ 458 $ — $ 24,866 Weighted-average period over which unrecognized compensation cost will be recognized: 1.1 years 2.0 years 1.6 years —
Stock-Based Compensation Expense in Future for Outstanding Awards	The following presents expected stock-based compensation expense in future periods for outstanding awards as of December 31, 2017: (add 000) 2018 $ 15,559 2019 8,299 2020 645 2021 269 2022 94 Total $ 24,866

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2017
Leases [Abstract]
Future Minimum Lease and Royalty Commitments for All Noncancelable Agreements	Future minimum lease and royalty commitments for all noncancelable agreements and capital lease obligations as of December 31, 2017 are as follows: (add 000) Capital Leases Operating Leases & Royalty Commitments 2018 $ 4,205 $ 121,234 2019 3,750 64,504 2020 2,247 58,731 2021 1,371 55,290 2022 913 52,781 Thereafter 3,993 345,860 Total 16,479 $ 698,400 Less: imputed interest (3,231 ) Present value of minimum lease payments 13,248 Less: current capital lease obligations (3,623 ) Long-term capital lease obligations $ 9,625
Future Minimum Lease Commitments for Capital Lease Obligations	Future minimum lease and royalty commitments for all noncancelable agreements and capital lease obligations as of December 31, 2017 are as follows: (add 000) Capital Leases Operating Leases & Royalty Commitments 2018 $ 4,205 $ 121,234 2019 3,750 64,504 2020 2,247 58,731 2021 1,371 55,290 2022 913 52,781 Thereafter 3,993 345,860 Total 16,479 $ 698,400 Less: imputed interest (3,231 ) Present value of minimum lease payments 13,248 Less: current capital lease obligations (3,623 ) Long-term capital lease obligations $ 9,625

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Schedule of Changes in Asset Retirement Obligations	The following shows the changes in the asset retirement obligations: years ended December 31: (add 000) 2017 2016 Balance at beginning of year $ 101,106 $ 89,604 Accretion expense 4,768 4,288 Liabilities incurred and liabilities assumed in business combinations 7,940 6,700 Liabilities settled (309 ) 166 Revisions in estimated cash flows (3,852 ) 348 Balance at end of year $ 109,653 $ 101,106
Schedule of Contractual Purchase Commitments	The Company’s contractual purchase commitments as of December 31, 2017 are as follows: (add 000) 2018 $ 238,280 2019 37,275 2020 10,983 2021 8,809 2022 1,616 Thereafter 18,502 Total $ 315,465

Segments (Tables)

Segments (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Financial Data for Continuing Operation for Company's Reportable Segments	The following tables display selected financial data for the Company’s reportable segments. years ended December 31 (add 000) Total revenues 2017 2016 2015 Mid-America Group $ 1,053,325 $ 1,017,098 $ 926,251 Southeast Group 362,555 321,078 304,472 West Group 2,279,723 2,223,515 2,062,968 Total Building Materials Business 3,695,603 3,561,691 3,293,691 Magnesia Specialties 269,991 257,058 245,879 Total $ 3,965,594 $ 3,818,749 $ 3,539,570 years ended December 31 (add 000) Net sales 2017 2016 2015 Mid-America Group $ 982,109 $ 945,123 $ 851,854 Southeast Group 348,409 304,451 285,302 West Group 2,142,839 2,089,192 1,903,452 Total Building Materials Business 3,473,357 3,338,766 3,040,608 Magnesia Specialties 248,071 238,001 227,508 Total $ 3,721,428 $ 3,576,767 $ 3,268,116 Gross profit (loss) Mid-America Group $ 335,394 $ 306,560 $ 257,002 Southeast Group 74,642 57,286 34,359 West Group 465,595 466,790 360,667 Total Building Materials Business 875,631 830,636 652,028 Magnesia Specialties 89,399 89,603 79,057 Corporate 6,910 (8,501 ) (4,165 ) Total $ 971,940 $ 911,738 $ 726,920 Selling, general and administrative expenses Mid-America Group $ 53,937 $ 52,712 $ 52,227 Southeast Group 17,144 17,245 18,353 West Group 102,650 95,631 92,988 Total Building Materials Business 173,731 165,588 163,568 Magnesia Specialties 9,537 9,617 9,408 Corporate 78,860 66,401 37,778 Total $ 262,128 $ 241,606 $ 210,754 Earnings (Loss) from operations Mid-America Group $ 284,789 $ 258,422 $ 207,619 Southeast Group 61,238 41,653 16,712 West Group 360,544 379,417 256,042 Total Building Materials Business 706,571 679,492 480,373 Magnesia Specialties 79,431 79,306 69,301 Corporate (85,621 ) (81,532 ) (55,507 ) Total $ 700,381 $ 677,266 $ 494,167 as of December 31 (add 000) Assets employed 2017 2016 2015 Mid-America Group $ 1,532,867 $ 1,406,526 $ 1,304,574 Southeast Group 616,344 594,967 583,369 West Group 5,014,231 4,904,018 4,561,432 Total Building Materials Business 7,163,442 6,905,511 6,449,375 Magnesia Specialties 152,257 150,969 147,795 Corporate 1,676,812 244,425 360,441 Total $ 8,992,511 $ 7,300,905 $ 6,957,611 years ended December 31 (add 000) Depreciation, depletion and amortization 2017 2016 2015 Mid-America Group $ 69,691 $ 64,295 $ 61,693 Southeast Group 30,780 30,590 31,644 West Group 169,853 164,653 147,619 Total Building Materials Business 270,324 259,538 240,956 Magnesia Specialties 10,070 10,354 9,992 Corporate 16,768 15,361 12,639 Total $ 297,162 $ 285,253 $ 263,587 Total property additions Mid-America Group $ 139,505 $ 152,014 $ 77,640 Southeast Group 34,636 30,588 12,155 West Group 240,793 338,795 244,844 Total Building Materials Business 414,934 521,397 334,639 Magnesia Specialties 11,129 8,944 8,916 Corporate 12,558 10,430 20,561 Total $ 438,621 $ 540,771 $ 364,116 Property additions through acquisitions Mid-America Group $ 60 $ 1,524 $ 4,385 Southeast Group — — — West Group 2,420 132,112 35,965 Total Building Materials Business 2,480 133,636 40,350 Magnesia Specialties — — — Corporate — — — Total $ 2,480 $ 133,636 $ 40,350
Total Revenues, Net Sales and Gross Profit by Product Line	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 are reported within in the West Group. The following tables, which are reconciled to consolidated amounts, provide total revenues, net sales and gross profit by line of business: Building Materials (further divided by product line) and Magnesia Specialties. Interproduct revenues and interproduct sales represent sales from the aggregates product line to the ready mixed concrete and asphalt and paving product lines and sales from the cement product line to the ready mixed concrete product line. years ended December 31 (add 000) Total revenues 2017 2016 2015 Aggregates $ 2,341,540 $ 2,267,574 $ 2,120,245 Cement 384,112 375,814 475,725 Ready Mixed Concrete 936,979 903,803 657,831 Asphalt and Paving 1 296,956 261,612 229,561 Less: Interproduct revenues 1 (263,984 ) (247,112 ) (189,671 ) Total Building Materials Business 3,695,603 3,561,691 3,293,691 Magnesia Specialties 269,991 257,058 245,879 Total $ 3,965,594 $ 3,818,749 $ 3,539,570 Net sales Aggregates $ 2,137,225 $ 2,060,876 $ 1,896,143 Cement 371,525 364,445 455,382 Ready Mixed Concrete 936,062 902,635 656,531 Asphalt and Paving 1 292,529 257,922 222,223 Less: Interproduct sales 1 (263,984 ) (247,112 ) (189,671 ) Total Building Materials Business 3,473,357 3,338,766 3,040,608 Magnesia Specialties 248,071 238,001 227,508 Total $ 3,721,428 $ 3,576,767 $ 3,268,116 1 Gross profit (loss) Aggregates $ 601,968 $ 558,318 $ 470,688 Cement 117,313 120,201 103,813 Ready Mixed Concrete 91,670 99,042 42,110 Asphalt and Paving 64,680 53,075 35,417 Total Building Materials Business 875,631 830,636 652,028 Magnesia Specialties 89,399 89,603 79,057 Corporate 6,910 (8,501 ) (4,165 ) Total $ 971,940 $ 911,738 $ 726,920
Domestic and Foreign Total Revenues	Domestic and foreign total revenues are as follows: years ended December 31 (add 000) 2017 2016 2015 Domestic $ 3,901,323 $ 3,761,651 $ 3,493,462 Foreign 64,271 57,098 46,108 Total $ 3,965,594 $ 3,818,749 $ 3,539,570

Supplemental Cash Flow Inform41

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Components of Change in Other Assets and Liabilities, Net	The components of the change in other assets and liabilities, net, are as follows: years ended December 31 (add 000) 2017 2016 2015 Other current and noncurrent assets $ (19,424 ) $ 9,171 $ (3,631 ) Accrued salaries, benefits and payroll taxes 136 16,942 (4,854 ) Accrued insurance and other taxes 4,866 (2,688 ) 4,425 Accrued income taxes (11,044 ) (12,523 ) (4,364 ) Accrued pension, postretirement and postemployment benefits 1,980 (15,955 ) (18,153 ) Other current and noncurrent liabilities 38,105 (6,053 ) (3,014 ) Change in other assets and liabilities, net $ 14,619 $ (11,106 ) $ (29,591 )
Schedule Of Other Significant Noncash Transactions [Text Block]	Noncash investing and financing activities are as follows: years ended December 31 (add 000) 2017 2016 2015 Accrued liabilities for purchases of property, plant and equipment $ 61,644 $ 38,566 $ 22,285 Acquisition of assets through capital lease $ 811 $ 1,399 $ 1,445 Acquisition of assets through asset exchange $ 2,476 $ - $ 5,000 Sale of asset to settle liability $ 900 $ - $ -
Supplemental Disclosures of Cash Flow Information	Supplemental disclosures of cash flow information are as follows: years ended December 31 (add 000) 2017 2016 2015 Cash paid for interest $ 78,902 $ 73,664 $ 71,011 Cash paid for income taxes $ 155,771 $ 124,342 $ 46,774

Accounting Policies - Additiona

Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)FacilityStatePlantshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)$ / shares
Significant Accounting Policies [Line Items]
Number of quarries and yards | Facility	282
Number of states with aggregates business sales by destination | State	30
Number of cement plants | Plant	2
Number of cement distribution facilities | Facility	5
Weighted-average fair value of stock option granted | $ / shares			$ 57.71
Minimum likelihood for recognition of tax benefit related to uncertain tax position	50.00%
Shares withheld for employees’ income tax obligations reclassified from operating activities	$ 11,805,000	$ 9,723,000	$ 7,601,000
ASU 2017-07 | Acquisition-Related Expenses, Net
Significant Accounting Policies [Line Items]
Reclassification of costs to nonoperating expense		774,000	2,118,000
ASU 2017-07 | Cost of Sales
Significant Accounting Policies [Line Items]
Reclassification of costs to nonoperating expense		2,772,000	5,153,000
ASU 2017-07 | Selling, General and Administrative Costs
Significant Accounting Policies [Line Items]
Reclassification of costs to nonoperating expense		6,399,000	7,480,000
ASU 2016-09
Significant Accounting Policies [Line Items]
Shares withheld for employees’ income tax obligations reclassified from operating activities		3,787,000	7,449,000
Excess tax benefits from share-based compensation reclassified to operating activities		$ 6,792,000	0
Stock Options
Significant Accounting Policies [Line Items]
Stock options issued | shares	0	0
Excess tax benefits from share-based compensation reclassified to operating activities	$ 3,483,000	$ 4,238,000	$ 551,000
Expendable Parts Inventory
Significant Accounting Policies [Line Items]
Allowance for inventories in excess of sales requisite Record period	5 years
Supplies Inventory
Significant Accounting Policies [Line Items]
Allowance for inventories in excess of sales requisite Record period	1 year
Minimum
Significant Accounting Policies [Line Items]
Number of ready mixed concrete and asphalt plants | Plant	152
Warranty term	9 months
Minimum | Inventory Finished Goods
Significant Accounting Policies [Line Items]
Allowance for inventories in excess of sales requisite Record period	12 months
Maximum
Significant Accounting Policies [Line Items]
Warranty term	1 year
Maximum | Inventory Finished Goods
Significant Accounting Policies [Line Items]
Allowance for inventories in excess of sales requisite Record period	5 years
Percentage of Aggregates Business Net Sales in Top Five Sales states | Geographic Concentration Risk | Sales Revenue Segment
Significant Accounting Policies [Line Items]
Total net sales, percentage	74.00%

Estimated Service Lives for Pro

Estimated Service Lives for Property, Plant and Equipment (Detail)	12 Months Ended
	Dec. 31, 2017
Building | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Service Lives, Years	5 years
Building | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Service Lives, Years	20 years
Machinery and Equipment | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Service Lives, Years	2 years
Machinery and Equipment | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Service Lives, Years	20 years
Land Improvements | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Service Lives, Years	5 years
Land Improvements | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Service Lives, Years	60 years

Summary of Key Assumptions Used

Summary of Key Assumptions Used in Determining Fair Value of Stock Options Awarded (Detail)	12 Months Ended
	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	2.20%
Dividend yield	1.20%
Volatility factor	36.10%
Expected term	8 years 6 months

Components of Changes in Accumu

Components of Changes in Accumulated Other Comprehensive Loss and Related Cumulative Noncurrent Deferred Tax Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 4,142,590	$ 4,060,177	$ 4,352,748
Other comprehensive (loss) earnings before reclassifications, net of tax	(6,922)	(32,576)	(10,658)
Amounts reclassified from accumulated other comprehensive loss, net of tax	8,505	7,511	11,195
Other comprehensive (loss) earnings, net of tax	1,583	(25,065)	537
Ending Balance	4,682,477	4,142,590	4,060,177
Cumulative noncurrent deferred tax assets at end of period	80,116	82,793	67,757
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(128,373)	(103,380)	(106,688)
Other comprehensive (loss) earnings before reclassifications, net of tax	(8,062)	(31,678)	(7,116)
Amounts reclassified from accumulated other comprehensive loss, net of tax	7,633	6,685	10,424
Other comprehensive (loss) earnings, net of tax	(429)	(24,993)	3,308
Ending Balance	(128,802)	(128,373)	(103,380)
Cumulative noncurrent deferred tax assets at end of period	79,938	82,044	66,467
Foreign Currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(1,162)	(264)	3,278
Other comprehensive (loss) earnings before reclassifications, net of tax	1,140	(898)	(3,542)
Other comprehensive (loss) earnings, net of tax	1,140	(898)	(3,542)
Ending Balance	(22)	(1,162)	(264)
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(1,152)	(1,978)	(2,749)
Amounts reclassified from accumulated other comprehensive loss, net of tax	872	826	771
Other comprehensive (loss) earnings, net of tax	872	826	771
Ending Balance	(280)	(1,152)	(1,978)
Cumulative noncurrent deferred tax assets at end of period	178	749	1,290
Accumulated Other Comprehensive (Loss) Earnings
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(130,687)	(105,622)	(106,159)
Ending Balance	$ (129,104)	$ (130,687)	$ (105,622)

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Additional interest expense	$ 91,487	$ 81,677	$ 76,287
Tax effect	(94,457)	181,584	124,863
Earnings from Continuing Operations	(8,505)	(7,511)	(11,195)
Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	(7,633)	(6,685)	(10,424)
Unamortized Value of Terminated Forward Starting Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Earnings from Continuing Operations	(872)	(826)	(771)
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefit Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Special plan termination benefits		764	2,085
Settlement charge	21	115
Prior service credit	(1,430)	(1,609)	(1,880)
Actuarial loss	13,774	11,575	16,850
Tax effect	(4,732)	(4,160)	(6,631)
Earnings from Continuing Operations	7,633	6,685	10,424
Reclassification out of Accumulated Other Comprehensive Income | Pension and Postretirement Benefit Plans | Other Nonoperating (Income) and Expenses, Net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications out of accumulated other comprehensive loss before taxes	12,365	10,845	17,055
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	1,443	1,367	1,280
Tax effect	(571)	(541)	(509)
Earnings from Continuing Operations	$ 872	$ 826	$ 771

Basic and Diluted Earnings Per

Basic and Diluted Earnings Per Common Share (Detail) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net earnings attributable to Martin Marietta	$ 713,342	$ 425,386	$ 288,792
Less: Distributed and undistributed earnings attributable to unvested awards	2,029	1,775	1,252
Basic and diluted net earnings attributable to common shareholders attributable to Martin Marietta	$ 711,313	$ 423,611	$ 287,540
Basic weighted-average common shares outstanding	62,932	63,610	66,770
Effect of dilutive employee and director awards	285	251	250
Diluted weighted-average common shares outstanding	63,217	63,861	67,020

Changes in Goodwill (Detail)

Changes in Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Balance at beginning of period	$ 2,159,337	$ 2,068,235
Acquisitions	230	91,174
Purchase price adjustments	723
Divestitures		(72)
Balance at end of period	2,160,290	2,159,337
Mid-America Group
Goodwill [Line Items]
Balance at beginning of period	281,403	281,403
Balance at end of period	281,403	281,403
Southeast Group
Goodwill [Line Items]
Balance at beginning of period	50,346	50,346
Balance at end of period	50,346	50,346
West Group
Goodwill [Line Items]
Balance at beginning of period	1,827,588	1,736,486
Acquisitions	230	91,174
Purchase price adjustments	723
Divestitures		(72)
Balance at end of period	$ 1,828,541	$ 1,827,588

Intangible Assets Subject to Am

Intangible Assets Subject to Amortization (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 540,727	$ 536,870
Accumulated Amortization	(68,255)	(54,155)
Net Balance	472,472	482,715
Noncompetition agreements
Finite-Lived Intangible Assets [Line Items]
Gross Amount	6,274	6,274
Accumulated Amortization	(6,144)	(6,106)
Net Balance	130	168
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Amount	45,755	45,755
Accumulated Amortization	(17,351)	(13,636)
Net Balance	28,404	32,119
Operating Permits
Finite-Lived Intangible Assets [Line Items]
Gross Amount	458,952	455,095
Accumulated Amortization	(26,436)	(19,493)
Net Balance	432,516	435,602
Use Rights And Other
Finite-Lived Intangible Assets [Line Items]
Gross Amount	16,946	16,946
Accumulated Amortization	(10,377)	(9,239)
Net Balance	6,569	7,707
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Amount	12,800	12,800
Accumulated Amortization	(7,947)	(5,681)
Net Balance	$ 4,853	$ 7,119

Intangible Assets Deemed to Ind

Intangible Assets Deemed to Indefinite Life and Not Being Amortized (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	$ 33,877	$ 28,597
Operating Permits
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	6,600	6,600
Use Rights Not Subject To Amortization
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	24,432	19,152
Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	2,845	2,845
Building Materials Business
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	31,312	26,032
Building Materials Business | Operating Permits
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	6,600	6,600
Building Materials Business | Use Rights Not Subject To Amortization
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	24,432	19,152
Building Materials Business | Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	280	280
Magnesia Specialties
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	2,565	2,565
Magnesia Specialties | Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite life intangible assets	$ 2,565	$ 2,565

Goodwill and Other Intangible51

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Other intangibles acquired	$ 10,270
Amortization expense of intangible assets	$ 14,178	$ 13,922	$ 13,962

Schedule of Acquired Intangible

Schedule of Acquired Intangibles (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Acquired Finite Lived Intangible Assets [Line Items]
Acquired intangibles subject to amortization and not subject to amortization	$ 10,270
Use Rights Not Subject To Amortization
Acquired Finite Lived Intangible Assets [Line Items]
Acquired intangibles not subject to amortization	5,280
Operating Permits
Acquired Finite Lived Intangible Assets [Line Items]
Acquired intangibles subject to amortization	$ 4,990
Acquired Finite-lived Intangible Assets, Useful Life		40 years

Estimated Amortization Expense

Estimated Amortization Expense of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
2,018	$ 13,070
2,019	12,114
2,020	12,078
2,021	11,387
2,022	9,805
Thereafter	414,018
Net Balance	$ 472,472	$ 482,715

Business Combinations - Additio

Business Combinations - Additional Information (Detail)	1 Months Ended		12 Months Ended
	Jul. 31, 2016USD ($)	Feb. 29, 2016T	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Jun. 26, 2017USD ($)
Business Combinations [Line Items]
Acquisition-related expenses incurred			$ 8,638,000	$ 909,000	$ 6,346,000
Bluegrass Materials Company
Business Combinations [Line Items]
Business acquisition agreed amount to acquire						$ 1,625,000,000
Acquisition-related expenses incurred			$ 8,638,000
Colorado | Minimum
Business Combinations [Line Items]
Acquisition of mineral reserves | T		500,000,000
Central Texas | Ratliff
Business Combinations [Line Items]
Ownership interest percentage under equity method, prior to acquisition	40.00%
Gain resulting from remeasure of existing interest to fair value upon closing of transaction	$ 5,863,000

Schedule of Accounts Receivable

Schedule of Accounts Receivable Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Customer receivables	$ 480,073	$ 456,508
Other current receivables	9,557	7,668
Accounts Receivable, gross	489,630	464,176
Less allowances	(2,390)	(6,266)
Total	$ 487,240	$ 457,910

Accounts Receivable, Net - Addi

Accounts Receivable, Net - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Due from unconsolidated affiliates	$ 2,819	$ 2,578

Schedule of Inventories Net (De

Schedule of Inventories Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Finished products	$ 552,999	$ 479,291
Products in process and raw materials	62,761	61,171
Supplies and expendable parts	128,792	116,024
Inventories, Gross	744,552	656,486
Less allowances	(143,961)	(134,862)
Total	$ 600,591	$ 521,624

Property Plant and Equipment Ne

Property Plant and Equipment Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Land and land improvements	$ 974,622	$ 915,158
Mineral reserves and interests	1,162,289	1,114,560
Buildings	154,564	151,115
Machinery and equipment	4,006,619	3,766,975
Construction in progress	199,973	167,722
Gross property, plant and equipment	6,498,067	6,115,530
Less accumulated depreciation, depletion and amortization	(2,905,254)	(2,692,135)
Total	$ 3,592,813	$ 3,423,395

Gross Asset Value and Accumulat

Gross Asset Value and Accumulated Amortization for Machinery and Equipment Recorded under Capital Lease (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Machinery and equipment under capital leases	$ 23,919	$ 23,117
Less accumulated amortization	(11,243)	(8,077)
Total	$ 12,676	$ 15,040

Property, Plant and Equipment60

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Depreciation, depletion and amortization	$ 279,808	$ 268,935	$ 246,874
Capitalized interest cost	3,616	3,543	$ 5,832
Property, plant and equipment, net	3,592,813	3,423,395
Bahamas And Canada
Property Plant And Equipment [Line Items]
Property, plant and equipment, net	$ 57,665	$ 58,332

Long-Term Debt (Detail)

Long-Term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total	$ 3,027,203	$ 1,686,189
Less current maturities	(299,909)	(180,036)
Long-term debt	2,727,294	1,506,153
Revolving Facility, Due 2022
Debt Instrument [Line Items]
Total		160,000
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Total	299,871	299,483
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Total	395,814	395,252
7% Debentures, Due 2025
Debt Instrument [Line Items]
Total	124,180	124,090
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total	296,628
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Total	494,352
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Total	228,033	227,975
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Total	591,688
Other Notes
Debt Instrument [Line Items]
Total	308	356
Floating Rate Notes, Due 2019
Debt Instrument [Line Items]
Total	298,102
Trade Receivable Facility
Debt Instrument [Line Items]
Total		180,000
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Total	$ 298,227
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Total		$ 299,033

Long-Term Debt (Parenthetical)

Long-Term Debt (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 20, 2017	Dec. 31, 2016
Revolving Facility, Due 2022
Debt Instrument [Line Items]
Maturity year	2,022
Credit Facility interest rate			1.86%
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Maturity year	2,018
Interest rate on notes	6.60%	6.60%
Interest rate	6.81%
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Maturity year	2,024
Interest rate on notes	4.25%
Interest rate	4.25%
7% Debentures, Due 2025
Debt Instrument [Line Items]
Maturity year	2,025
Interest rate on notes	7.00%
Interest rate	7.12%
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Maturity year	2,027
Interest rate on notes	3.45%
Interest rate	3.47%
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Maturity year	2,027
Interest rate on notes	3.50%
Interest rate	3.53%
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Maturity year	2,037
Interest rate on notes	6.25%
Interest rate	6.45%
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Maturity year	2,047
Interest rate on notes	4.25%
Interest rate	4.27%
Floating Rate Notes, Due 2019
Debt Instrument [Line Items]
Maturity year	2,019
Interest rate	2.13%
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Maturity year	2,020
Interest rate	2.10%
Floating Rate Notes, Due 2017
Debt Instrument [Line Items]
Maturity year	2,017
Interest rate			2.10%
Trade Receivable Facility
Debt Instrument [Line Items]
Credit Facility interest rate			1.34%

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail) - USD ($)	Dec. 20, 2017	May 22, 2017	Dec. 05, 2016	Apr. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Required offer price to repurchase senior notes if change of control repurchase event and downgrade below investment grade credit rating occurs	101.00%				101.00%
Redemption price percentage of principal amount of notes redeemed		100.00%
Maximum consolidated debt reduction for unrestricted cash and cash equivalents for debt covenant calculation					$ 200,000,000
Outstanding letters of credit					45,028,000
Additional interest expense					1,443,000	$ 1,367,000	$ 1,280,000
Scenario, Forecast
Debt Instrument [Line Items]
Increase in annual interest expense due to ongoing amortization of the terminated value of the swap agreements				$ 463,000
Minimum
Debt Instrument [Line Items]
Reduction of consolidated debt in the debt ratio calculation					$ 50,000,000
Including Acquisition Bridge Debt | Maximum
Debt Instrument [Line Items]
Debt covenant					3.50
Excluding Acquisition Bridge Debt | Maximum
Debt Instrument [Line Items]
Debt covenant					3.75
Revolving Facility
Debt Instrument [Line Items]
Credit facility commitment			$ 700,000,000
Senior unsecured revolving facility, maturity period			5 years
Debt instrument maturity period					Dec. 5, 2022
Debt intrument exteded maturity period					1 year
Outstanding letters of credit					$ 2,301,000	2,507,000
Short-term Line of Credit
Debt Instrument [Line Items]
Credit facility commitment					5,000,000
Outstanding borrowing under credit facility					$ 0	0
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Interest rate on notes	6.60%				6.60%
Maturity year					2,018
Senior notes	$ 300,000,000				$ 300,000,000
Maturity date	Apr. 15, 2018				Apr. 15, 2018
7% Debentures, Due 2025
Debt Instrument [Line Items]
Interest rate on notes					7.00%
Maturity year					2,025
Senior notes					$ 125,000,000
Maturity date					Dec. 1, 2025
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Interest rate on notes					6.25%
Maturity year					2,037
Senior notes					$ 230,000,000
Maturity date					May 1, 2037
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Interest rate on notes					4.25%
Maturity year					2,024
Senior notes					$ 400,000,000
Maturity date					Jul. 2, 2024
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Interest rate on notes					3.45%
Maturity year					2,027
Senior notes		$ 300,000,000			$ 300,000,000
Debt instrument, redemption description					The 3.450% Senior Notes may be redeemed in whole or in part prior to March 1, 2027 at a make-whole redemption price, or on or after March 1, 2027 at a redemption price equal to 100% of the principal amount of the notes to be redeemed, and in either case plus unpaid interest, if any, accrued thereon to, but excluding, the date of redemption.
Maturity date					Jun. 1, 2027
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Interest rate on notes					3.50%
Maturity year					2,027
Senior notes	$ 500,000,000				$ 500,000,000
Maturity date					Dec. 15, 2027
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Interest rate on notes					4.25%
Maturity year					2,047
Senior notes	600,000,000				$ 600,000,000
Maturity date					Dec. 15, 2047
Floating Rate Notes, Due 2019
Debt Instrument [Line Items]
Maturity year					2,019
Senior notes	$ 300,000,000				$ 300,000,000
Maturity date	Dec. 20, 2019				Dec. 20, 2019
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Maturity year					2,020
Senior notes		$ 300,000,000			$ 300,000,000
Maturity date					May 22, 2020
Floating Rate Notes, Due 2020 | Three-month LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		0.65%
Trade Receivable Facility
Debt Instrument [Line Items]
Credit facility commitment					$ 300,000,000
Debt instrument maturity period					Sep. 26, 2018
Credit facility borrowing base					$ 338,784,000	$ 332,302,000
Trade Receivable Facility | London Interbank Offered Rate(LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate					0.725%

Schedule of Principal Amount, E

Schedule of Principal Amount, Effective Interest Rate and Maturity Date for Corporation's Senior Notes (Detail) - USD ($)	Dec. 20, 2017	Dec. 31, 2017	May 22, 2017
6.60% Senior Notes, Due 2018
Debt Instrument [Line Items]
Principal Amount	$ 300,000,000	$ 300,000,000
Effective Interest Rate		6.81%
Maturity Date	Apr. 15, 2018	Apr. 15, 2018
4.25% Senior Notes, Due 2024
Debt Instrument [Line Items]
Principal Amount		$ 400,000,000
Effective Interest Rate		4.25%
Maturity Date		Jul. 2, 2024
7% Debentures, Due 2025
Debt Instrument [Line Items]
Principal Amount		$ 125,000,000
Effective Interest Rate		7.12%
Maturity Date		Dec. 1, 2025
3.450% Senior Notes, Due 2027
Debt Instrument [Line Items]
Principal Amount		$ 300,000,000	$ 300,000,000
Effective Interest Rate		3.47%
Maturity Date		Jun. 1, 2027
3.500% Senior Notes, Due 2027
Debt Instrument [Line Items]
Principal Amount	$ 500,000,000	$ 500,000,000
Effective Interest Rate		3.53%
Maturity Date		Dec. 15, 2027
6.25% Senior Notes, Due 2037
Debt Instrument [Line Items]
Principal Amount		$ 230,000,000
Effective Interest Rate		6.45%
Maturity Date		May 1, 2037
4.250% Senior Notes, Due 2047
Debt Instrument [Line Items]
Principal Amount	600,000,000	$ 600,000,000
Effective Interest Rate		4.27%
Maturity Date		Dec. 15, 2047
Floating Rate Notes, Due 2019
Debt Instrument [Line Items]
Principal Amount	$ 300,000,000	$ 300,000,000
Effective Interest Rate		2.13%
Debt Instrument Effective Interest Rate		Three-month LIBOR + 0.50%
Maturity Date	Dec. 20, 2019	Dec. 20, 2019
Floating Rate Notes, Due 2020
Debt Instrument [Line Items]
Principal Amount		$ 300,000,000	$ 300,000,000
Effective Interest Rate		2.10%
Debt Instrument Effective Interest Rate		Three-month LIBOR + 0.65%
Maturity Date		May 22, 2020

Schedule of Corporation's Long-

Schedule of Corporation's Long-Term Debt Maturities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2,018	$ 299,909
2,019	298,157
2,020	298,286
2,021	65
2,022	90
Thereafter	2,130,696
Total	$ 3,027,203	$ 1,686,189

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Long-term debt, carrying values	$ 3,027,203	$ 1,686,189
Long-term debt, fair values	$ 3,144,902	$ 1,752,338

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Federal statutory corporate income tax rate		35.00%	35.00%	35.00%
Tax benefit for the provisional impact of 2017 Tax Act		$ 258,103,000
Income tax benefit from net operating loss (NOL) carryforwards utilized			$ 11,852,000	$ 156,554,000
Income tax benefits attributable to stock-based compensation			6,792,000	871,000
Foreign pretax earnings (loss)		$ 10,566,000	3,865,000	(1,175,000)
Tax deduction, percentage		9.00%
Increased net earnings		$ 15,461,000	$ 13,583,000	$ 222,000
Increased net earnings, per share		$ 0.25	$ 0.21	$ 0.01
Operating loss carryforwards, expiration dates		2,036
Deferred tax assets recognized		$ 11,780,000	$ 10,507,000
Deferred tax asset, valuation allowance		10,085,000	8,303,000
Alternative Minimum Tax credit carryforward			17,192,000
Deferred tax asset carryforward, net of unrecognized tax benefits			2,771,000
2017 Tax Act executive compensation deduction limitation amount		1,000,000
Unrecognized tax benefits that would impact effective tax rate		10,399,000	11,603,000	$ 7,975,000
Estimated unrecognized tax benefits, decrease as a result of tax position taken in next year		$ 3,333,000
Expiration date of statute of limitations		2,014
Tax refund, Per share		$ 0.06		$ 0.04
Tax refund		$ 3,922,000		$ 2,364,000
Earliest Tax Year
Income Taxes [Line Items]
Expiration date of statute of limitations		2,010
Open tax years		2,011
Latest Tax Year
Income Taxes [Line Items]
Expiration date of statute of limitations		2,013
Open tax years		2,017
Canadian Subsidiary
Income Taxes [Line Items]
Undistributed net earnings		$ 43,587,000
Bahamian Subsidiary
Income Taxes [Line Items]
Undistributed net earnings		0
Federal Tax Authority
Income Taxes [Line Items]
Operating loss carryforwards, amount		0	0
State Tax Authority
Income Taxes [Line Items]
Operating loss carryforwards, amount		197,916,000	220,532,000
Domestic Tax Authority
Income Taxes [Line Items]
Domestic and foreign tax credits, amount		$ 1,342,000	1,441,000
Domestic tax credits, expiration year		2,031
Deferred tax assets recognized		$ 1,060,000	937,000
Deferred tax asset, valuation allowance		$ 264,000	$ 218,000
Scenario, Forecast
Income Taxes [Line Items]
Federal statutory corporate income tax rate	21.00%

Components of Income Tax (Benef

Components of Income Tax (Benefit) Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Federal income taxes:
Current	$ 129,236	$ 97,975	$ 20,627
Deferred	(239,304)	68,899	85,295
Total federal income tax (benefit) expense	(110,068)	166,874	105,922
State income taxes:
Current	14,843	15,189	18,153
Deferred	(882)	(1,149)	930
Total state income taxes	13,961	14,040	19,083
Foreign income taxes:
Current	1,175	1,064	99
Deferred	475	(394)	(241)
Total foreign income taxes	1,650	670	(142)
Income tax (benefit) expense	$ (94,457)	$ 181,584	$ 124,863

Summary of Effective Income Tax

Summary of Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Statutory tax rate	35.00%	35.00%	35.00%
Provisional remeasurement of deferred taxes due to 2017 Tax Act	(41.70%)
Effect of statutory depletion	(5.60%)	(5.40%)	(7.80%)
State income taxes, net of federal tax benefit	1.50%	1.50%	3.00%
Domestic production deduction	(2.20%)	(2.00%)	(0.10%)
Stock based compensation	(1.00%)	(0.10%)	(0.30%)
Other items	(1.30%)	0.90%	0.40%
Effective income tax rate	(15.30%)	29.90%	30.20%

Components of Deferred Tax Asse

Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets related to:
Employee benefits	$ 16,059	$ 61,462
Inventories	56,242	71,490
Valuation and other reserves	22,989	38,206
Net operating loss carryforwards	11,780	10,507
Accumulated other comprehensive loss	80,116	82,793	$ 67,757
AMT credit carryforward		2,771
Gross deferred tax assets	187,186	267,229
Valuation allowance on deferred tax assets	(10,349)	(8,521)
Total net deferred tax assets	176,837	258,708
Deferred tax liabilities related to:
Property, plant and equipment	(407,400)	(635,576)
Goodwill and other intangibles	(168,506)	(268,999)
Other items, net	(11,654)	(17,152)
Total deferred tax liabilities	(587,560)	(921,727)
Deferred income taxes, net	$ (410,723)	$ (663,019)

Schedule of Unrecognized Tax Be

Schedule of Unrecognized Tax Benefits Excluding Interest Correlative Effects (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning of year	$ 21,807	$ 18,727	$ 21,107
Gross increases – tax positions in prior years	1,396	2,401	3,079
Gross decreases – tax positions in prior years	(672)	(1,924)	(3,512)
Gross increases – tax positions in current year	4,961	4,650	4,978
Gross decreases – tax positions in current year	(946)	(2,047)	(594)
Lapse of statute of limitations	(4,179)		(6,331)
Unrecognized tax benefits at end of year	$ 22,367	$ 21,807	$ 18,727

Schedule of Components of Net P

Schedule of Components of Net Periodic Benefit Credit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 26,805	$ 22,167	$ 23,001
Interest cost	36,101	35,879	33,151
Expected return on assets	(39,759)	(37,699)	(36,385)
Prior service cost (credit)	311	350	422
Actuarial (gain) loss	14,138	12,074	17,159
Transition asset	(1)	(1)	(1)
Settlement charge (credit)	21	124
Termination benefit charge		764	2,085
Total net periodic benefit cost (credit)	37,616	33,658	39,432
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	80	85	137
Interest cost	727	863	928
Prior service cost (credit)	(1,741)	(1,959)	(2,302)
Actuarial (gain) loss	(364)	(499)	(309)
Settlement charge (credit)		(9)
Total net periodic benefit cost (credit)	$ (1,298)	$ (1,519)	$ (1,546)

Net Periodic Benefit Cost Recog

Net Periodic Benefit Cost Recognized in Comprehensive Earnings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain)	$ 13,343	$ 52,028	$ 9,916
Prior service (cost) credit	(311)	(350)	(422)
Actuarial gain (loss)	(14,138)	(12,074)	(17,159)
Transition asset	1	1	1
Special plan termination benefits		(764)	(2,085)
Settlement (charge) credit	(21)	(124)
Net prior service cost (credit)			2,338
Total	(1,126)	38,717	(7,411)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss (gain)	1,236	686	(626)
Prior service (cost) credit	1,741	1,959	2,302
Actuarial gain (loss)	364	499	309
Settlement (charge) credit		9
Net prior service cost (credit)	(3,902)	(1,326)
Total	$ (561)	$ 1,827	$ 1,985

Net Periodic Benefit Credit or

Net Periodic Benefit Credit or Cost Not Yet Recognized (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Pension
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit) - Gross	$ 115	$ 425
Actuarial (gain) loss - Gross	217,240	218,056
Transition asset - Gross	(6)	(7)
Total - Gross	217,349	218,474
Prior service cost (credit) - Net of tax	71	261
Actuarial (gain) loss - Net of tax	134,066	133,083
Transition asset - Net of tax	(4)	(4)
Total - Net of tax	134,133	133,340
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit) - Gross	(6,314)	(4,153)
Actuarial (gain) loss - Gross	(2,256)	(3,857)
Total - Gross	(8,570)	(8,010)
Prior service cost (credit) - Net of tax	(3,899)	(2,551)
Actuarial (gain) loss - Net of tax	(1,393)	(2,369)
Total - Net of tax	$ (5,292)	$ (4,920)

Retirement Plans Postretirement

Retirement Plans Postretirement and Postemployment Benefits - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation for defined benefit pension plans	$ 792,912,000	$ 752,659,000
Combined pension plan and SERP contributions	30,903,000	44,763,000
Corporation's matching obligations	$ 14,893,000	13,235,000	$ 12,444,000
Defined contribution plan name	401(a)
Accrued postemployment benefits	$ 1,119,000	1,146,000
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of pension asset equity securities in mid and large capitalization funds	50.00%
Pension
Defined Benefit Plan Disclosure [Line Items]
Prior service cost, recognized in net periodic benefit cost	$ 104,000
Prior service cost, recognized in net periodic benefit cost - deferred tax asset and liability	26,000
Actuarial gain (loss), recognized in net periodic benefit cost	13,184,000
Actuarial gain (loss), recognized in net periodic benefit cost - deferred tax asset and liability	3,263,000
Transition assets, recognized in net periodic benefit cost	1,000
Combined pension plan and SERP contributions	30,903,000	44,763,000
SERP Plans
Defined Benefit Plan Disclosure [Line Items]
Estimated contribution of pension plans	37,400,000
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service cost, recognized in net periodic benefit cost	2,445,000
Actuarial gain (loss), recognized in net periodic benefit cost	226,000
Combined pension plan and SERP contributions	3,385,000	$ 3,127,000
Prior service cost, recognized in net periodic benefit cost - deferred tax asset and liability	605,000
Actuarial gain (loss) , recognized in net periodic benefit cost - deferred tax asset and liability	56,000
Postretirement Health Care Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated contribution of pension plans	$ 2,560,000

Change in Projected Benefit Obl

Change in Projected Benefit Obligation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension
Defined Benefit Plan Disclosure [Line Items]
Net projected benefit obligation at beginning of year	$ 831,849	$ 754,543
Service cost	26,805	22,167	$ 23,001
Interest cost	36,101	35,879	33,151
Actuarial loss	56,675	49,760
Gross benefits paid	(72,095)	(30,500)
Net projected benefit obligation at end of year	879,335	831,849	754,543
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net projected benefit obligation at beginning of year	20,591	23,408
Service cost	80	85	137
Interest cost	727	863	928
Participants' contributions	3,421	2,616
Actuarial loss	1,236	688
Gross benefits paid	(6,806)	(5,743)
Plan amendments	(3,902)	(1,326)
Net projected benefit obligation at end of year	$ 15,347	$ 20,591	$ 23,408

Schedule of Change In Plan Asse

Schedule of Change In Plan Assets (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of year	$ 596,207,000
Employer contributions	30,903,000	$ 44,763,000
Balance at end of year	638,106,000	596,207,000
Pension
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of year	596,207,000	546,512,000
Actual return on plan assets, net	83,091,000	35,432,000
Employer contributions	30,903,000	44,763,000
Gross benefits paid	(72,095,000)	(30,500,000)
Balance at end of year	638,106,000	596,207,000
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	3,385,000	3,127,000
Participants' contributions	3,421,000	2,616,000
Gross benefits paid	$ (6,806,000)	$ (5,743,000)

Schedule of Funded Status (Deta

Schedule of Funded Status (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Pension
Defined Benefit Plan Disclosure [Line Items]
Funded status of the plan at end of year	$ (241,229)	$ (235,642)
Accrued benefit cost	(241,229)	(235,642)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Funded status of the plan at end of year	(15,347)	(20,591)
Accrued benefit cost	$ (15,347)	$ (20,591)

Schedule of Amounts Recognized

Schedule of Amounts Recognized on Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Current pension and postretirement benefits	$ (11,092)	$ (6,223)
Noncurrent pension, postretirement and postemployment benefits	(230,137)	(229,419)
Net amount recognized at end of year	(241,229)	(235,642)
Current pension and postretirement benefits	(2,560)	(3,070)
Noncurrent pension, postretirement and postemployment benefits	(12,787)	(17,521)
Net amount recognized at end of year	$ (15,347)	$ (20,591)

Schedule of Accumulated Benefit

Schedule of Accumulated Benefit Obligations in Excess of Plan Assets (Detail) - Pension - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 879,335	$ 831,849
Accumulated benefit obligation	792,912	752,659
Fair value of plan assets	$ 638,106	$ 596,207

Schedule of Weighted-Average As

Schedule of Weighted-Average Assumptions (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.76%	4.29%
Rate of increase in future compensation levels	4.50%	4.50%
Discount rate	4.29%	4.67%	4.25%
Rate of increase in future compensation levels	4.50%	4.50%	4.50%
Expected long-term rate of return on assets	6.75%	7.00%	7.00%
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.47%	3.78%
Discount rate	3.78%	4.25%	3.83%

Schedule of Target Assets Alloc

Schedule of Target Assets Allocation (Detail)	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Other securities, Target Allocation	100.00%
Total	100.00%	100.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Other securities, Target Allocation	54.00%
Total	57.00%	57.00%
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Other securities, Target Allocation	30.00%
Total	29.00%	28.00%
Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Other securities, Target Allocation	8.00%
Total	7.00%	7.00%
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Other securities, Target Allocation	8.00%
Total	7.00%	8.00%

Schedule of Fair Values of Pens

Schedule of Fair Values of Pension Plan Assets by Asset Class and Fair Value Hierarchy Level (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	$ 638,106	$ 596,207
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	46,467	44,890
Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	45,604	44,036
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	41	145
Quoted Prices In Active Markets For Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	41	145
Quoted Prices In Active Markets For Identical Assets (Level 1) | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	41	145
Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	545,994	507,136
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	92,071	88,926
Significant Unobservable Inputs (Level 3) | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	46,467	44,890
Significant Unobservable Inputs (Level 3) | Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	45,604	44,036
Mid Sized To Large Cap | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	177,497	169,176
Mid Sized To Large Cap | Significant Observable Inputs (Level 2) | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	177,497	169,176
International And Emerging Growth Funds | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	186,272	169,678
International And Emerging Growth Funds | Significant Observable Inputs (Level 2) | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	186,272	169,678
Core Fixed Income | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	182,225	168,282
Core Fixed Income | Significant Observable Inputs (Level 2) | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	$ 182,225	$ 168,282

Schedule of Change In Fair Valu

Schedule of Change In Fair Value Of Pension Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of year	$ 44,890	$ 23,242
Purchases, sales, settlements, net	(83)	18,579
Actual return on plan assets held at period end	1,660	3,069
Balance at end of year	46,467	44,890
Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Balance at beginning of year	44,036	39,219
Purchases, sales, settlements, net		3,100
Actual return on plan assets held at period end	1,568	1,717
Balance at end of year	$ 45,604	$ 44,036

Schedule of Expected Benefit Pa

Schedule of Expected Benefit Payments (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Pension
Defined Benefit Plan Disclosure [Line Items]
2,018	$ 43,090
2,019	40,894
2,020	43,143
2,021	44,568
2,022	46,359
Years 2023 - 2027	261,475
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
2,018	2,560
2,019	1,610
2,020	1,557
2,021	1,470
2,022	1,393
Years 2023 - 2027	$ 4,888

Schedule of Assumed Health Care

Schedule of Assumed Health Care Cost Trend Rate (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Health care cost trend rate assumed for next year	7.00%	7.00%
Rate to which the cost trend rate gradually declines	5.00%	5.00%
Year the rate reaches the ultimate rate	2,022	2,021

Schedule of One Percentage-Poin

Schedule of One Percentage-Point Change In Assumed Health Care Cost Trend Rate (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Compensation And Retirement Disclosure [Abstract]
Total service and interest cost components, Increase	$ 41
Postretirement benefit obligation, Increase	783
Total service and interest cost components, Decrease	(34)
Postretirement benefit obligation, Decrease	$ (631)

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of incentive compensation to acquire shares, maximum	50.00%
Percentage of discount rate to market value on the incentive compensation	20.00%
Company normal retirement age	62 years
Common stock price	$ 221.04
Non-qualified stock options received by nonemployee member of board of directors	3,000
Weighted-average grant-date exercise price of options granted			$ 154.58
Aggregate intrinsic values of options exercised	$ 13,247	$ 22,571	$ 7,318
Aggregate intrinsic values for options outstanding	39,135
Aggregate intrinsic values for options exercisable	$ 35,984
Awards available for grant	836,000
Additional shares registration under the plan		800,000
Common stock reserved for future issuance	250,000
Common stock issued under the plan	42,025
Texas Industries Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options issued to former option holders	821,282
Number of options issued per single option	0.7
Employee stock options expiration period	90 days
Options granted in 2015 and 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	10 years
Options granted prior to 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	8 years
Options granted prior to 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options expiration date	10 years
Incentive Compensation Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of stock awards, granted	$ 208.68	$ 124.41	$ 108.53
Aggregate intrinsic values for stock awards	$ 3,377
Common stock price	$ 221.04
Aggregate intrinsic values of stock awards, distributed	$ 2,601	$ 1,941	$ 983
Restricted Stock - Service Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of stock awards, granted	$ 213.76	$ 128.48	$ 154.26
Restricted Stock - Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value of stock awards, granted	$ 207.73	$ 124.41	$ 108.53
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic values for stock awards	$ 100,538
Aggregate intrinsic values of stock awards, distributed	15,771	$ 9,738	$ 11,387
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits from share-based compensation reclassified to operating activities	$ 3,483	$ 4,238	$ 551
Common stock issued under the plan	0	0
Legacy TXI plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards available for grant	0
Directors' Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	300,000
Common stock issued under the plan	2,132	3,699	4,035

Summary Information for Restric

Summary Information for Restricted Stock Awards and Incentive Compensation Stock Awards (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restricted Stock - Service Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards, January 1, 2017	307,317
Number of Awards, Awarded	80,181
Number of Awards, Distributed	(68,828)
Number of Awards, Forfeited	(3,830)
Number of Awards, December 31, 2017	314,840	307,317
Weighted-Average Grant-Date Fair Value, January 1, 2017	$ 125.36
Weighted-Average Grant-Date Fair Value, Awarded	213.76	$ 128.48	$ 154.26
Weighted-Average Grant-Date Fair Value, Distributed	121.40
Weighted-Average Grant-Date Fair Value, Forfeited	156.40
Weighted-Average Grant-Date Fair Value, December 31, 2017	$ 151.84	$ 125.36
Restricted Stock - Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards, January 1, 2017	111,317
Number of Awards, Awarded	47,997
Number of Awards, Distributed	(17,692)
Number of Awards, Forfeited	(1,623)
Number of Awards, December 31, 2017	139,999	111,317
Weighted-Average Grant-Date Fair Value, January 1, 2017	$ 122.22
Weighted-Average Grant-Date Fair Value, Awarded	207.73	$ 124.41	108.53
Weighted-Average Grant-Date Fair Value, Distributed	129.14
Weighted-Average Grant-Date Fair Value, Forfeited	150.38
Weighted-Average Grant-Date Fair Value, December 31, 2017	$ 150.34	$ 122.22
Incentive Compensation Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards, January 1, 2017	40,549
Number of Awards, Awarded	19,981
Number of Awards, Distributed	(21,784)
Number of Awards, Forfeited	(236)
Number of Awards, December 31, 2017	38,510	40,549
Weighted-Average Grant-Date Fair Value, January 1, 2017	$ 114.44
Weighted-Average Grant-Date Fair Value, Awarded	208.68	$ 124.41	$ 108.53
Weighted-Average Grant-Date Fair Value, Distributed	108.44
Weighted-Average Grant-Date Fair Value, Forfeited	124.41
Weighted-Average Grant-Date Fair Value, December 31, 2017	$ 166.67	$ 114.44

Summary Information for Stock O

Summary Information for Stock Options (Detail)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Outstanding at January 1, 2017 | shares	406,891
Number of Options, Exercised | shares	(104,093)
Number of Options, Terminated | shares	(840)
Number of Options, Outstanding at December 31, 2017 | shares	301,958
Number of Options, Exercisable at December 31, 2017 | shares	261,380
Weighted-Average Exercise Price, Outstanding at January 1, 2017 | $ / shares	$ 93.27
Weighted-Average Exercise Price, Exercised | $ / shares	98.68
Weighted-Average Exercise Price, Terminated | $ / shares	80.52
Weighted-Average Exercise Price, Outstanding at December 31, 2017 | $ / shares	91.44
Weighted-Average Exercise Price, Exercisable at December 31, 2017 | $ / shares	$ 83.37
Weighted-Average Remaining Contractual Life (years), Outstanding at December 31, 2017	3 years 7 months 6 days
Weighted-Average Remaining Contractual Life (years), Exercisable at December 31, 2017	3 years 1 month 6 days

Schedule of Stock-Based Compens

Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 30,460	$ 20,481	$ 13,589
Unrecognized compensation cost	24,866
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	684	1,646	2,679
Unrecognized compensation cost	$ 292
Weighted-average period over which unrecognized compensation cost will be recognized:	1 year 1 month 6 days
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 28,657	17,747	9,809
Unrecognized compensation cost	$ 24,116
Weighted-average period over which unrecognized compensation cost will be recognized:	2 years
Incentive Compensation Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 661	442	376
Unrecognized compensation cost	$ 458
Weighted-average period over which unrecognized compensation cost will be recognized:	1 year 7 months 6 days
Directors' Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 458	$ 646	$ 725

Stock-Based Compensation Expens

Stock-Based Compensation Expense in Future for Outstanding Awards (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
2,018	$ 15,559
2,019	8,299
2,020	645
2,021	269
2,022	94
Total	$ 24,866

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases [Abstract]
Lease expenses for operating lease	$ 90,731	$ 85,945	$ 80,417
Total royalties	51,827	$ 55,257	$ 53,658
Future minimum lease commitments related to contracts of affreightment	$ 204,418

Future Minimum Lease and Royalt

Future Minimum Lease and Royalty Commitments for All Noncancelable Agreements and Capital Lease Obligations (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Capital Leases
2,018	$ 4,205
2,019	3,750
2,020	2,247
2,021	1,371
2,022	913
Thereafter	3,993
Total	16,479
Less: imputed interest	(3,231)
Present value of minimum lease payments	13,248
Less: current capital lease obligations	(3,623)
Long-term capital lease obligations	9,625
Operating Leases & Royalty Commitments
2,018	121,234
2,019	64,504
2,020	58,731
2,021	55,290
2,022	52,781
Thereafter	345,860
Total	$ 698,400

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock reserved for issuance under stock-based award plans	1,986,000
Stock Repurchased During Period, Shares	457,742	1,587,987	3,285,380
Common stock remaining under repurchase authorization	14,668,891
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, par value	$ 0.01	$ 0.01
Percentage ownership by person or group making rights exercisable	15.00%
Rights exercisable price, per share	$ 315
Class B Preferred Stock
Class of Stock [Line Items]
Preferred stock reserved for issuance under stock-based plans	200,000
Maximum
Class of Stock [Line Items]
Stock repurchase program, shares authorized to be repurchased	20,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)Bond	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Jan. 31, 2018USD ($)
Commitments and Contingencies [Line Items]
Asset retirement obligation depreciation and accretion	$ 8,682,000	$ 8,823,000	$ 6,767,000
Liability reserve for insurance claims	48,061,000	42,184,000
Outstanding letters of credit	45,028,000
Surety bonds	348,253,000
Balance of top 5 surety bonds	$ 90,625,000
Group of bonds, amount | Bond	5
Percentage of top 5 surety bonds	26.00%
Due from affiliate	$ 15,775,000
Guarantee of affiliate's obligations	25,000,000
Purchase commitments for property, plant and equipment		315,465,000
Capital expenditures	$ 83,748,000	62,927,000	$ 116,681,000
Percentage of employees represented in labor union	11.00%
Woodville
Commitments and Contingencies [Line Items]
Collective bargaining agreement expiration month year	2018-05
Magnesia Specialties
Commitments and Contingencies [Line Items]
Percentage of employees represented in labor union	100.00%
Collective bargaining agreement expiration month year	2019-08
Capital Addition Purchase Commitments
Commitments and Contingencies [Line Items]
Purchase commitments for property, plant and equipment	$ 191,582,000
Energy And Service Contracts
Commitments and Contingencies [Line Items]
Purchase commitments for property, plant and equipment	$ 123,883,000
Subsequent Event
Commitments and Contingencies [Line Items]
Guarantee of affiliate's obligations				$ 15,500,000
Revolving Line Of Credit Expires In August 2015
Commitments and Contingencies [Line Items]
Line of credit maturity period	2020-03
Interest-Only Note Due December 31, 2019
Commitments and Contingencies [Line Items]
Due from affiliate	$ 6,000,000
Revolving Credit Facility
Commitments and Contingencies [Line Items]
Outstanding letters of credit	$ 2,301,000	$ 2,507,000

Changes in Asset Retirement Obl

Changes in Asset Retirement Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Balance at beginning of year	$ 101,106	$ 89,604
Accretion expense	4,768	4,288
Liabilities incurred and liabilities assumed in business combinations	7,940	6,700
Liabilities settled	(309)	166
Revisions in estimated cash flows	(3,852)	348
Balance at end of year	$ 109,653	$ 101,106

Contractual Purchase Commitment

Contractual Purchase Commitments (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 238,280
2,019	37,275
2,020	10,983
2,021	8,809
2,022	1,616
Thereafter	18,502
Total	$ 315,465

Segments - Additional Informati

Segments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017Segment
Segment Reporting [Abstract]
Reportable business segments	3

Financial Data for Continuing O

Financial Data for Continuing Operations for Company's Reportable Segments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenues	$ 3,965,594	$ 3,818,749	$ 3,539,570
Net sales	3,721,428	3,576,767	3,268,116
Gross profit (loss)	971,940	911,738	726,920
Selling, general and administrative expenses	262,128	241,606	210,754
Earnings (Loss) from operations	700,381	677,266	494,167
Assets employed	8,992,511	7,300,905	6,957,611
Depreciation, depletion and amortization	297,162	285,253	263,587
Total property additions	438,621	540,771	364,116
Property additions through acquisitions	2,480	133,636	40,350
Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	3,695,603	3,561,691	3,293,691
Net sales	3,473,357	3,338,766	3,040,608
Gross profit (loss)	875,631	830,636	652,028
Selling, general and administrative expenses	173,731	165,588	163,568
Earnings (Loss) from operations	706,571	679,492	480,373
Assets employed	7,163,442	6,905,511	6,449,375
Depreciation, depletion and amortization	270,324	259,538	240,956
Total property additions	414,934	521,397	334,639
Property additions through acquisitions	2,480	133,636	40,350
Operating Segments | Mid-America Group | Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	1,053,325	1,017,098	926,251
Net sales	982,109	945,123	851,854
Gross profit (loss)	335,394	306,560	257,002
Selling, general and administrative expenses	53,937	52,712	52,227
Earnings (Loss) from operations	284,789	258,422	207,619
Assets employed	1,532,867	1,406,526	1,304,574
Depreciation, depletion and amortization	69,691	64,295	61,693
Total property additions	139,505	152,014	77,640
Property additions through acquisitions	60	1,524	4,385
Operating Segments | Southeast Group | Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	362,555	321,078	304,472
Net sales	348,409	304,451	285,302
Gross profit (loss)	74,642	57,286	34,359
Selling, general and administrative expenses	17,144	17,245	18,353
Earnings (Loss) from operations	61,238	41,653	16,712
Assets employed	616,344	594,967	583,369
Depreciation, depletion and amortization	30,780	30,590	31,644
Total property additions	34,636	30,588	12,155
Operating Segments | West Group | Building Materials Business
Segment Reporting Information [Line Items]
Total revenues	2,279,723	2,223,515	2,062,968
Net sales	2,142,839	2,089,192	1,903,452
Gross profit (loss)	465,595	466,790	360,667
Selling, general and administrative expenses	102,650	95,631	92,988
Earnings (Loss) from operations	360,544	379,417	256,042
Assets employed	5,014,231	4,904,018	4,561,432
Depreciation, depletion and amortization	169,853	164,653	147,619
Total property additions	240,793	338,795	244,844
Property additions through acquisitions	2,420	132,112	35,965
Operating Segments | Magnesia Specialties
Segment Reporting Information [Line Items]
Total revenues	269,991	257,058	245,879
Net sales	248,071	238,001	227,508
Gross profit (loss)	89,399	89,603	79,057
Selling, general and administrative expenses	9,537	9,617	9,408
Earnings (Loss) from operations	79,431	79,306	69,301
Assets employed	152,257	150,969	147,795
Depreciation, depletion and amortization	10,070	10,354	9,992
Total property additions	11,129	8,944	8,916
Corporate
Segment Reporting Information [Line Items]
Gross profit (loss)	6,910	(8,501)	(4,165)
Selling, general and administrative expenses	78,860	66,401	37,778
Earnings (Loss) from operations	(85,621)	(81,532)	(55,507)
Assets employed	1,676,812	244,425	360,441
Depreciation, depletion and amortization	16,768	15,361	12,639
Total property additions	$ 12,558	$ 10,430	$ 20,561

Total Revenues, Net Sales and G

Total Revenues, Net Sales and Gross Profit by Product Line (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Product Information [Line Items]
Total revenues		$ 3,965,594,000	$ 3,818,749,000	$ 3,539,570,000
Net sales		3,721,428,000	3,576,767,000	3,268,116,000
Gross profit (loss)		971,940,000	911,738,000	726,920,000
Interproduct revenues / sales
Product Information [Line Items]
Total revenues	[1]	(263,984,000)	(247,112,000)	(189,671,000)
Net sales	[1]	(263,984,000)	(247,112,000)	(189,671,000)
Corporate
Product Information [Line Items]
Gross profit (loss)		6,910,000	(8,501,000)	(4,165,000)
Building Materials Business | Operating Segments
Product Information [Line Items]
Total revenues		3,695,603,000	3,561,691,000	3,293,691,000
Net sales		3,473,357,000	3,338,766,000	3,040,608,000
Gross profit (loss)		875,631,000	830,636,000	652,028,000
Magnesia Specialties | Operating Segments
Product Information [Line Items]
Total revenues		269,991,000	257,058,000	245,879,000
Net sales		248,071,000	238,001,000	227,508,000
Gross profit (loss)		89,399,000	89,603,000	79,057,000
Aggregates | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total revenues		2,341,540,000	2,267,574,000	2,120,245,000
Net sales		2,137,225,000	2,060,876,000	1,896,143,000
Gross profit (loss)		601,968,000	558,318,000	470,688,000
Ready Mixed Concrete | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total revenues		936,979,000	903,803,000	657,831,000
Net sales		936,062,000	902,635,000	656,531,000
Gross profit (loss)		91,670,000	99,042,000	42,110,000
Asphalt and Paving | Interproduct revenues / sales
Product Information [Line Items]
Total revenues			83,500,000	61,400,000
Net sales			83,500,000	61,400,000
Asphalt and Paving | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total revenues	[1]	296,956,000	261,612,000	229,561,000
Net sales	[1]	292,529,000	257,922,000	222,223,000
Gross profit (loss)		64,680,000	53,075,000	35,417,000
Cement | Building Materials Business | Operating Segments | Reportable Subsegments
Product Information [Line Items]
Total revenues		384,112,000	375,814,000	475,725,000
Net sales		371,525,000	364,445,000	455,382,000
Gross profit (loss)		$ 117,313,000	$ 120,201,000	$ 103,813,000
[1]	2016 and 2015 amounts have been revised to reflect the elimination of $83,500,000 and $61,400,000, respectively, of asphalt sales to the paving operations within that product line.

Total Revenues, Net Sales an102

Total Revenues, Net Sales and Gross Profit by Product Line (Parenthetical) (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Product Information [Line Items]
Total revenues		$ 3,965,594,000	$ 3,818,749,000	$ 3,539,570,000
Net sales		3,721,428,000	3,576,767,000	3,268,116,000
Interproduct revenues / sales
Product Information [Line Items]
Total revenues	[1]	(263,984,000)	(247,112,000)	(189,671,000)
Net sales	[1]	$ (263,984,000)	(247,112,000)	(189,671,000)
Asphalt and Paving | Interproduct revenues / sales
Product Information [Line Items]
Total revenues			83,500,000	61,400,000
Net sales			$ 83,500,000	$ 61,400,000
[1]	2016 and 2015 amounts have been revised to reflect the elimination of $83,500,000 and $61,400,000, respectively, of asphalt sales to the paving operations within that product line.

Domestic and Foreign Total Reve

Domestic and Foreign Total Revenues (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenues	$ 3,965,594	$ 3,818,749	$ 3,539,570
Domestic
Segment Reporting Information [Line Items]
Total revenues	3,901,323	3,761,651	3,493,462
Foreign
Segment Reporting Information [Line Items]
Total revenues	$ 64,271	$ 57,098	$ 46,108

Components of Change in Other A

Components of Change in Other Assets and Liabilities Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Other current and noncurrent assets	$ (19,424)	$ 9,171	$ (3,631)
Accrued salaries, benefits and payroll taxes	136	16,942	(4,854)
Accrued insurance and other taxes	4,866	(2,688)	4,425
Accrued income taxes	(11,044)	(12,523)	(4,364)
Accrued pension, postretirement and postemployment benefits	1,980	(15,955)	(18,153)
Other current and noncurrent liabilities	38,105	(6,053)	(3,014)
Change in other assets and liabilities, net	$ 14,619	$ (11,106)	$ (29,591)

Schedule Of Noncash Investing a

Schedule Of Noncash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Accrued liabilities for purchases of property, plant and equipment	$ 61,644	$ 38,566	$ 22,285
Acquisition of assets through capital lease	811	$ 1,399	1,445
Acquisition of assets through asset exchange	2,476		$ 5,000
Sale of asset to settle liability	$ 900

Supplemental Disclosures of Cas

Supplemental Disclosures of Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest	$ 78,902	$ 73,664	$ 71,011
Cash paid for income taxes	$ 155,771	$ 124,342	$ 46,774

Other Operating Expenses and107

Other Operating Expenses and (Income), Net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Component Of Other Income And Expense [Line Items]
Other operating expenses and (income), net	$ 793,000	$ (8,043,000)	$ 15,653,000
Gains on sale of assets	19,366,000	$ (410,000)	$ (14,093,000)
Nonrecurring repair costs	12,668,000
Other Operating Expenses and (Income), Net
Component Of Other Income And Expense [Line Items]
Gains on sale of assets	19,366,000
Other Operating Expenses and (Income), Net | Executive
Component Of Other Income And Expense [Line Items]
Retirement expense	$ 10,813,000

Schedule II - Valuation and 108

Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Allowance for doubtful accounts
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period		$ 6,266	$ 6,940		$ 4,077
Charged to costs and expenses					2,863
Deductions-describe	[1]	3,876	674
Balance at end of period		2,390	6,266		6,940
Allowance for uncollectible notes receivable
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period		437	585		1,486
Charged to costs and expenses					0
Deductions-describe	[1]	210	148		901
Balance at end of period		227	437		585
Inventory valuation allowance
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period		134,862	130,584		119,189
Charged to costs and expenses		9,099	4,160		13,365
Charged to other accounts-describe		0	118	[2]	1,400	[2]
Deductions-describe		0			3,370	[3]
Balance at end of period		$ 143,961	$ 134,862		$ 130,584
[1]	Write off of uncollectible accounts and change in estimates.
[2]	Application of reserve policy to acquired inventories.
[3]	Divestitures.