CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Activities
Net earnings (loss)	$ 18,924,000	$ (39,678,000)
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation, depletion, accretion and amortization	69,406,000	66,723,000
Net gain on sale of property, plant & equipment and businesses	(555,000)	(6,375,000)
Contributions to pension plans	(2,343,000)	(1,447,000)
Share-based compensation	4,321,000	4,700,000
Excess tax benefits from share-based compensation	(21,235,000)	(7,575,000)
Deferred tax provision (benefit)	(17,879,000)	(11,592,000)
Cost of debt purchase	0	21,734,000
Changes in assets and liabilities before initial effects of business acquisitions and dispositions	19,668,000	4,575,000
Other, net	(27,450,000)	(11,911,000)
Net cash provided by operating activities	42,857,000	19,154,000
Investing Activities
Purchases of property, plant & equipment	(108,284,000)	(49,611,000)
Proceeds from sale of property, plant & equipment	1,086,000	2,354,000
Payment for businesses acquired, net of acquired cash	(1,611,000)	0
Decrease in restricted cash	1,150,000	0
Other, net	1,549,000	(334,000)
Net cash used for investing activities	(106,110,000)	(47,591,000)
Financing Activities
Payment of current maturities and long-term debt	(5,000)	(145,918,000)
Proceeds from issuance of long-term debt	0	400,000,000
Purchases of common stock	(23,433,000)	0
Dividends paid	(26,718,000)	(13,253,000)
Proceeds from exercise of stock options	0	31,416,000
Excess tax benefits from share-based compensation	21,235,000	7,575,000
Other, net	0	1,000
Net cash provided by (used for) financing activities	(28,921,000)	279,821,000
Net increase (decrease) in cash and cash equivalents	(92,174,000)	251,384,000
Cash and cash equivalents at beginning of year	284,060,000	141,273,000
Cash and cash equivalents at end of period	$ 191,886,000	$ 392,657,000