CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities
Net earnings	$ 212,631	$ 165,060
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation, depletion, accretion and amortization	167,072	148,339
Net gain on sale of property, plant & equipment and businesses	(6,270)	(3,142)
Contributions to pension plans	(104,794)	(4,744)
Share-based compensation expense	14,763	13,671
Deferred tax expense (benefit)	40,549	2,901
Cost of debt purchase	6,922	0
Changes in assets and liabilities before initial effects of business acquisitions and dispositions	(55,415)	(170,701)
Other, net	302	3,838
Net cash provided by operating activities	275,760	155,222
Investing Activities
Purchases of property, plant & equipment	(247,166)	(291,034)
Proceeds from sale of property, plant & equipment	8,523	8,530
Proceeds from sale of businesses	11,256	0
Payment for businesses acquired, net of acquired cash	(218,996)	(210,562)
Other, net	(10,226)	405
Net cash used for investing activities	(456,609)	(492,661)
Financing Activities
Proceeds from short-term debt	506,200	5,000
Payment of short-term debt	(146,200)	(5,000)
Payment of current maturities and long-term debt	(892,044)	(235,007)
Proceeds from issuance of long-term debt	850,000	1,600,000
Debt issuance and exchange costs	(45,513)	(15,046)
Settlements of interest rate derivatives	3,378	0
Purchases of common stock	(74,921)	(60,303)
Dividends paid	(74,196)	(66,194)
Share-based compensation, shares withheld for taxes	(31,386)	(24,231)
Net cash provided by financing activities	95,318	1,199,219
Net increase (decrease) in cash and cash equivalents and restricted cash	(85,531)	861,780
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	$ 61,115	$ 1,129,799