CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Total revenues	$ 895,143,000	$ 791,143,000	$ 1,526,436,000	$ 1,365,563,000
Cost of revenues	660,694,000	616,355,000	1,214,122,000	1,156,682,000
Gross profit	234,449,000	174,788,000	312,314,000	208,881,000
Selling, administrative and general expenses	69,197,000	67,615,000	135,960,000	133,733,000
Gain on sale of property, plant & equipment and businesses, net	249,000	1,162,000	6,624,000	237,526,000
Restructuring charges	(1,280,000)	0	(4,098,000)	0
Other operating expense, net	(10,445,000)	(5,089,000)	(14,346,000)	(14,758,000)
Operating earnings	153,776,000	103,246,000	164,534,000	297,916,000
Other nonoperating income (expense), net	(439,000)	1,798,000	542,000	4,622,000
Interest expense, net	83,651,000	40,551,000	146,132,000	160,639,000
Earnings from continuing operations before income taxes	69,686,000	64,493,000	18,944,000	141,899,000
Provision for income taxes	19,867,000	17,982,000	5,791,000	40,882,000
Earnings from continuing operations	49,819,000	46,511,000	13,153,000	101,017,000
Loss on discontinued operations, net of tax	(1,657,000)	(544,000)	(4,669,000)	(1,054,000)
Net earnings	48,162,000	45,967,000	8,484,000	99,963,000
Other comprehensive income, net of tax
Reclassification adjustment for cash flow hedges	3,077,000	584,000	5,325,000	3,569,000
Adjustment for funded status of benefit plans	0	0	0	2,943,000
Amortization of actuarial loss and prior service cost for benefit plans	2,697,000	1,115,000	5,378,000	(108,000)
Other comprehensive income	5,774,000	1,699,000	10,703,000	6,404,000
Comprehensive income (loss)	$ 53,936,000	$ 47,666,000	$ 19,187,000	$ 106,367,000
Basic earnings (loss) per share
Continuing operations	$ 0.37	$ 0.35	$ 0.10	$ 0.77
Discontinued operations	(0.01)	0.00	(0.04)	(0.01)
Net earnings	0.36	0.35	0.06	0.76
Diluted earnings (loss) per share
Continuing operations	0.37	0.35	0.10	0.76
Discontinued operations	(0.01)	0.00	(0.04)	(0.01)
Net earnings (loss)	$ 0.36	$ 0.35	$ 0.06	$ 0.75
Weighted-average common shares outstanding
Basic	133,103	131,149	132,882	130,980
Assuming dilution	135,234	132,876	134,689	132,468
Cash dividends per share of common stock	$ 0.10	$ 0.05	$ 0.20	$ 0.10
Depreciation, depletion, accretion and amortization	$ 68,384,000	$ 68,323,000	$ 135,108,000	$ 137,702,000
Effective tax rate from continuing operations	28.50%	27.90%	30.60%	28.80%