CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Activities
Net earnings	$ 52,979	$ 44,921
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation, depletion, accretion and amortization	81,439	71,563
Net gain on sale of property, plant & equipment and businesses	(4,164)	(369)
Contributions to pension plans	(102,443)	(2,374)
Share-based compensation expense	6,794	6,488
Deferred tax expense (benefit)	7,968	153
Cost of debt purchase	6,922	0
Changes in assets and liabilities before initial effects of business acquisitions and dispositions	39,832	(28,069)
Other, net	3,641	1,839
Net cash provided by operating activities	92,968	94,152
Investing Activities
Purchases of property, plant & equipment	(128,688)	(133,022)
Proceeds from sale of property, plant & equipment	1,701	1,239
Proceeds from sale of businesses	11,256	0
Payment for businesses acquired, net of acquired cash	(76,259)	(185,067)
Other, net	(34)	0
Net cash used for investing activities	(192,024)	(316,850)
Financing Activities
Proceeds from short-term debt	252,000	0
Payment of short-term debt	(52,000)	0
Payment of current maturities and long-term debt	(892,038)	(5)
Proceeds from issuance of long-term debt	850,000	350,000
Debt issuance and exchange costs	(45,513)	(4,565)
Settlements of interest rate derivatives	3,378	0
Purchases of common stock	(55,568)	(49,221)
Dividends paid	(37,176)	(33,152)
Share-based compensation, shares withheld for taxes	(24,159)	(21,421)
Net cash provided by (used for) financing activities	(1,076)	241,636
Net increase (decrease) in cash and cash equivalents and restricted cash	(100,132)	18,938
Cash and cash equivalents and restricted cash at beginning of year	146,646	268,019
Cash and cash equivalents and restricted cash at end of period	$ 46,514	$ 286,957