CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Total revenues	[1]	$ 1,322,575	$ 1,327,682	$ 2,371,817	$ 2,324,193
Cost of revenues		926,056	957,180	1,773,575	1,762,016
Gross profit		396,519	370,502	598,242	562,177
Selling, administrative and general expenses		91,205	95,689	177,635	185,957
Gain (loss) on sale of property, plant & businesses		(258)	3,451	741	10,748
Other operating expense, net		(6,160)	(2,190)	(10,151)	(6,461)
Operating earnings		298,896	276,074	411,197	380,507
Other nonoperating income (expense), net		7,367	2,466	(1,969)	5,595
Interest expense, net		33,954	33,035	64,727	65,969
Earnings from continuing operations before income taxes		272,309	245,505	344,501	320,133
Income tax expense		61,352	47,598	73,546	58,291
Earnings from continuing operations		210,957	197,907	270,955	261,842
Loss on discontinued operations, net of tax		(1,041)	(349)	(781)	(985)
Net earnings		209,916	197,558	270,174	260,857
Other comprehensive income, net of tax
Deferred loss on interest rate derivative		0	0	(14,679)	0
Amortization of prior interest rate derivative loss		194	56	988	111
Amortization of actuarial loss and prior service cost for benefit plans		1,695	336	3,390	571
Other comprehensive income (loss)		1,889	392	(10,301)	682
Comprehensive income		$ 211,805	$ 197,950	$ 259,873	$ 261,539
Basic earnings (loss) per share
Continuing operations		$ 1.59	$ 1.50	$ 2.04	$ 1.98
Discontinued operations		(0.01)	(0.01)	0.00	(0.01)
Net earnings		1.58	1.49	2.04	1.97
Diluted earnings (loss) per share
Continuing operations		1.58	1.48	2.03	1.97
Discontinued operations		0.00	0.00	0.00	(0.01)
Net earnings		$ 1.58	$ 1.48	$ 2.03	$ 1.96
Weighted-average common shares outstanding
Basic		132,552	132,269	132,560	132,157
Assuming dilution		133,115	133,354	133,154	133,199
Depreciation, depletion, accretion and amortization		$ 99,470	$ 93,497	$ 194,951	$ 182,677
Effective tax rate from continuing operations		22.50%	19.40%	21.30%	18.20%

[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 and Texas West market — Arizona, California and New Mexico