CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Product sales	$ 795,096	$ 746,392	$ 2,034,521	$ 1,915,032
Freight and delivery revenues	78,483	67,176	204,621	175,431
Total revenues	873,579	813,568	2,239,142	2,090,463
Cost of revenues	664,537	654,585	1,821,220	1,780,930
Gross profit	209,042	158,983	417,922	309,533
Selling, administrative and general expenses	66,074	65,854	199,808	195,411
Gain on sale of property, plant & equipment and businesses, net	1,002	9,350	238,527	36,869
Restructuring charges	(750)	0	(750)	(1,509)
Other operating expense, net	(2,889)	(2,712)	(17,645)	(12,907)
Operating earnings	140,331	99,767	438,246	136,575
Other nonoperating income (expense), net	(593)	2,310	4,030	4,968
Interest expense, net	40,891	49,134	201,531	152,757
Earnings (loss) from continuing operations before income taxes	98,847	52,943	240,745	(11,214)
Provision for (benefit from) income taxes	31,066	10,793	71,947	(21,874)
Earnings from continuing operations	67,781	42,150	168,798	10,660
Earnings (loss) on discontinued operations, net of tax	(842)	(787)	(1,896)	4,640
Net earnings	66,939	41,363	166,902	15,300
Other comprehensive income, net of tax
Reclassification adjustment for cash flow hedges	598	679	4,167	2,368
Adjustment for funded status of benefit plans	0	0	2,943	60,299
Amortization of actuarial loss and prior service cost for benefit plans	1,114	2,111	1,006	8,974
Other comprehensive income	1,712	2,790	8,116	71,641
Comprehensive income	68,651	44,153	175,018	86,941
Basic earnings (loss) per share
Continuing operations	$ 0.51	$ 0.32	$ 1.29	$ 0.08
Discontinued operations	$ 0.00	$ 0.00	$ (0.02)	$ 0.04
Net earnings	$ 0.51	$ 0.32	$ 1.27	$ 0.12
Diluted earnings (loss) per share
Continuing operations	$ 0.51	$ 0.32	$ 1.27	$ 0.08
Discontinued operations	$ (0.01)	$ (0.01)	$ (0.01)	$ 0.04
Net earnings	$ 0.50	$ 0.31	$ 1.26	$ 0.12
Weighted-average common shares outstanding
Basic	131,797	130,266	131,256	130,234
Assuming dilution	133,369	131,320	132,759	131,368
Cash dividends per share of common stock	$ 0.06	$ 0.01	$ 0.16	$ 0.03
Depreciation, depletion, accretion and amortization	$ 71,157	$ 78,320	$ 208,858	$ 230,877
Effective tax rate from continuing operations	31.40%	20.40%	29.90%	195.10%