CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Total revenues	[1]	$ 1,049,242	$ 996,511
Cost of revenues		847,519	804,836
Gross profit		201,723	191,675
Selling, administrative and general expenses		86,430	90,268
Gain on sale of property, plant & equipment and businesses		999	7,297
Other operating expense, net		(3,991)	(4,271)
Operating earnings		112,301	104,433
Other nonoperating income (expense), net		(9,336)	3,129
Interest expense, net		30,773	32,934
Earnings from continuing operations before income taxes		72,192	74,628
Income tax expense		12,194	10,693
Earnings from continuing operations		59,998	63,935
Earnings (loss) on discontinued operations, net of tax		260	(636)
Net earnings		60,258	63,299
Other comprehensive income, net of tax
Deferred loss on interest rate derivative		(14,680)	0
Amortization of prior interest rate derivative loss		794	55
Amortization of actuarial loss and prior service cost for benefit plans		1,695	235
Other comprehensive income (loss)		(12,191)	290
Comprehensive income		$ 48,067	$ 63,589
Basic earnings (loss) per share
Continuing operations		$ 0.45	$ 0.48
Discontinued operations		0.00	0.00
Net earnings		0.45	0.48
Diluted earnings (loss) per share
Continuing operations		0.45	0.48
Discontinued operations		0.00	0.00
Net earnings		$ 0.45	$ 0.48
Weighted-average common shares outstanding
Basic		132,567	132,043
Assuming dilution		133,259	133,054
Depreciation, depletion, accretion and amortization		$ 95,480	$ 89,181
Effective tax rate from continuing operations		16.90%	14.30%

[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