Consolidated Statements of Earnings and Comprehensive Earnings (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Total Revenues	$ 1,202,403	$ 1,063,524	$ 2,004,407	$ 1,907,383
Total Cost of Revenues	886,486	789,430	1,578,098	1,486,223
Gross Profit	315,917	274,094	426,309	421,160
Selling, general & administrative expenses	71,070	68,373	141,191	137,908
Acquisition-related expenses, net	12,126	1,982	12,836	2,004
Other operating income, net	(31,232)	(9,113)	(30,752)	(8,754)
Earnings from Operations	263,953	212,852	303,034	290,002
Interest expense	32,971	24,045	68,059	44,896
Other nonoperating income, net	(7,122)	(5,420)	(15,626)	(5,956)
Earnings before income tax expense	238,104	194,227	250,601	251,062
Income tax expense	52,601	51,986	55,058	66,514
Consolidated net earnings	185,503	142,241	195,543	184,548
Less: Net earnings (loss) attributable to noncontrolling interests	126	(38)	143	(65)
Net Earnings Attributable to Martin Marietta Materials, Inc.	185,377	142,279	195,400	184,613
Consolidated Comprehensive Earnings: (See Note 1)
Earnings attributable to Martin Marietta Materials, Inc.	186,979	144,798	198,621	189,394
Earnings (Loss) attributable to noncontrolling interests	126	(37)	144	(63)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 187,105	$ 144,761	$ 198,765	$ 189,331
Net Earnings Attributable to Martin Marietta Materials, Inc. Per Common Share:
Basic attributable to common shareholders	$ 2.94	$ 2.26	$ 3.10	$ 2.92
Diluted attributable to common shareholders	$ 2.92	$ 2.25	$ 3.08	$ 2.91
Weighted-Average Common Shares Outstanding:
Basic	63,021	62,858	62,989	62,961
Diluted	63,285	63,141	63,253	63,246
Cash Dividends Per Common Share	$ 0.44	$ 0.42	$ 0.88	$ 0.84
Products and Services
Total Revenues	$ 1,128,777	$ 996,843	$ 1,882,082	$ 1,789,159
Total Cost of Revenues	812,430	722,195	1,454,049	1,366,813
Freight
Total Revenues	73,626	66,681	122,325	118,224
Total Cost of Revenues	$ 74,056	$ 67,235	$ 124,049	$ 119,410