CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating Activities
Net earnings (loss)	$ (39,678,000)	$ 53,995,000
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation, depletion, accretion and amortization	66,723,000	69,378,000
Net gain on sale of property, plant & equipment and businesses	(6,375,000)	(236,364,000)
Contributions to pension plans	(1,447,000)	(1,355,000)
Share-based compensation	4,700,000	4,319,000
Excess tax benefits from share-based compensation	(7,575,000)	(2,997,000)
Deferred tax provision (benefit)	(11,592,000)	(7,648,000)
Cost of debt purchase	21,734,000	72,949,000
Changes in assets and liabilities before initial effects of business acquisitions and dispositions	4,575,000	40,127,000
Other, net	(11,911,000)	2,624,000
Net cash provided by (used for) operating activities	19,154,000	(4,972,000)
Investing Activities
Purchases of property, plant & equipment	(49,611,000)	(46,006,000)
Proceeds from sale of property, plant & equipment	2,354,000	17,785,000
Proceeds from sale of businesses, net of transaction costs	0	720,056,000
Increase in restricted cash	0	(63,024,000)
Other, net	(334,000)	0
Net cash provided by (used for) investing activities	(47,591,000)	628,811,000
Financing Activities
Payment of current maturities, long-term debt and line of credit	(145,918,000)	(579,676,000)
Proceeds from issuance of long-term debt	400,000,000	0
Proceeds from issuance of common stock	0	22,808,000
Dividends paid	(13,253,000)	(6,531,000)
Proceeds from exercise of stock options	31,416,000	11,599,000
Excess tax benefits from share-based compensation	7,575,000	2,997,000
Other, net	1,000	(1,000)
Net cash provided by (used for) financing activities	279,821,000	(548,804,000)
Net increase in cash and cash equivalents	251,384,000	75,035,000
Cash and cash equivalents at beginning of year	141,273,000	193,738,000
Cash and cash equivalents at end of period	$ 392,657,000	$ 268,773,000