CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Total revenues	[1]	$ 1,418,758	$ 1,240,197	$ 3,742,951	$ 3,294,822
Cost of revenues		1,018,115	897,055	2,780,131	2,469,161
Gross profit		400,643	343,142	962,820	825,661
Selling, administrative and general expenses		88,789	81,606	274,747	248,989
Gain on sale of property, plant & equipment and businesses		234	2,104	10,982	8,374
Other operating expense, net		(8,712)	(14,456)	(15,173)	(23,822)
Operating earnings		303,376	249,184	683,882	561,224
Other nonoperating income, net		359	4,890	5,954	12,708
Interest expense, net		32,197	33,547	98,165	104,566
Earnings from continuing operations before income taxes		271,538	220,527	591,671	469,366
Income tax expense		53,472	40,663	111,764	75,805
Earnings from continuing operations		218,066	179,864	479,907	393,561
Loss on discontinued operations, net of tax		(2,353)	(713)	(3,338)	(1,778)
Net earnings		215,713	179,151	476,569	391,783
Other comprehensive income, net of tax
Deferred gain on interest rate derivative		0	0	0	2,496
Amortization of prior interest rate derivative loss		57	53	169	171
Amortization of actuarial loss and prior service cost for benefit plans		286	1,091	856	3,274
Other comprehensive income		343	1,144	1,025	5,941
Comprehensive income		$ 216,056	$ 180,295	$ 477,594	$ 397,724
Basic earnings (loss) per share
Continuing operations		$ 1.65	$ 1.36	$ 3.63	$ 2.97
Discontinued operations		(0.02)	(0.01)	(0.03)	(0.01)
Net earnings		1.63	1.35	3.60	2.96
Diluted earnings (loss) per share
Continuing operations		1.63	1.34	3.60	2.94
Discontinued operations		(0.01)	0.00	(0.02)	(0.02)
Net earnings		$ 1.62	$ 1.34	$ 3.58	$ 2.92
Weighted-average common shares outstanding
Basic		132,414	132,392	132,244	132,505
Assuming dilution		133,375	133,894	133,273	134,079
Depreciation, depletion, accretion and amortization		$ 96,247	$ 89,390	$ 278,925	$ 256,463
Effective tax rate from continuing operations		19.70%	18.40%	18.90%	16.20%

[1] ¹ The geographic markets are defined by states/countries as follows: East market — Arkansas, Delaware, Illinois, Kentucky, Maryland, North Carolina, Pennsylvania, Tennessee, Virginia, and Washington D.C. Gulf Coast market — Alabama, Florida, Georgia, Louisiana, Mexico, Mississippi, Oklahoma, South Carolina, Texas and the Bahamas West market — Arizona, California and New Mexico