CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating Activities
Net earnings	$ 8,484,000	$ 99,963,000
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation, depletion, accretion and amortization	135,108,000	137,702,000
Net gain on sale of property, plant & equipment and businesses	(6,624,000)	(237,526,000)
Contributions to pension plans	(2,822,000)	(2,791,000)
Share-based compensation	9,679,000	11,928,000
Excess tax benefits from share-based compensation	(11,457,000)	(3,242,000)
Deferred tax provision (benefit)	(11,656,000)	24,000
Cost of debt purchase	67,075,000	72,949,000
Changes in assets and liabilities before initial effects of business acquisitions and dispositions	(109,790,000)	(59,893,000)
Other, net	(13,360,000)	3,786,000
Net cash provided by operating activities	64,637,000	22,900,000
Investing Activities
Purchases of property, plant & equipment	(148,721,000)	(116,312,000)
Proceeds from sale of property, plant & equipment	3,419,000	20,454,000
Proceeds from sale of businesses, net of transaction costs	0	719,089,000
Payment for businesses acquired, net of acquired cash	(21,387,000)	(207,000)
Increase in restricted cash	0	(62,087,000)
Other, net	(334,000)	0
Net cash provided by (used for) investing activities	(167,023,000)	560,937,000
Financing Activities
Proceeds from line of credit	284,000,000	0
Payment of current maturities, long-term debt and line of credit	(676,445,000)	(579,694,000)
Proceeds from issuance of long-term debt	400,000,000	0
Debt and line of credit issuance costs	(7,382,000)	0
Proceeds from issuance of common stock	0	27,539,000
Dividends paid	(26,549,000)	(13,074,000)
Proceeds from exercise of stock options	50,769,000	12,095,000
Excess tax benefits from share-based compensation	11,457,000	3,242,000
Other, net	(1,000)	1,000
Net cash provided by (used for) financing activities	35,849,000	(549,891,000)
Net increase (decrease) in cash and cash equivalents	(66,537,000)	33,946,000
Cash and cash equivalents at beginning of year	141,273,000	193,738,000
Cash and cash equivalents at end of period	$ 74,736,000	$ 227,684,000