CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities
Net earnings	$ 584,480	$ 617,662	$ 515,805
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation, depletion, accretion and amortization	396,806	374,596	346,246
Noncash operating lease expense	38,272	35,344	0
Net gain on sale of property, plant & equipment and businesses	(3,997)	(23,752)	(14,944)
Contributions to pension plans	(8,819)	(8,882)	(109,631)
Share-based compensation expense	32,991	31,843	25,215
Deferred tax expense	62,018	76,011	64,639
Cost of debt purchase	0	0	6,922
Increase (decrease) in liabilities excluding the initial effects of business acquisitions and dispositions
Accounts and notes receivable	13,413	(29,734)	63,230
Inventories	9,801	(28,273)	(34,976)
Prepaid expenses	2,585	5,990	(2,167)
Other assets	(14,430)	(61,195)	(58,489)
Increase (decrease) in liabilities excluding the initial effects of business acquisitions and dispositions
Accrued interest and income taxes	775	(4,644)	12,148
Trade payables and other accruals	(6,942)	21,788	40,181
Other noncurrent liabilities	(44,912)	(51,150)	(26,901)
Other, net	8,318	28,518	5,499
Net cash provided by operating activities	1,070,359	984,122	832,777
Investing Activities
Purchases of property, plant & equipment	(362,194)	(384,094)	(469,088)
Proceeds from sale of property, plant & equipment	11,461	22,661	22,210
Proceeds from sale of businesses	968	1,744	11,256
Payment for businesses acquired, net of acquired cash	(43,223)	(44,151)	(221,419)
Other, net	11,474	(11,997)	(12,850)
Net cash used for investing activities	(381,514)	(415,837)	(669,891)
Financing Activities
Proceeds from short-term debt	0	366,900	739,900
Payment of short-term debt	0	(499,900)	(606,900)
Payment of current maturities and long-term debt	(250,025)	(23)	(892,055)
Proceeds from issuance of long-term debt	750,000	0	850,000
Debt issuance and exchange costs	(15,394)	0	(45,513)
Settlements of interest rate derivatives	(19,863)	0	3,378
Purchases of common stock	(26,132)	(2,602)	(133,983)
Dividends paid	(180,216)	(163,973)	(148,109)
Share-based compensation, shares withheld for taxes	(22,144)	(38,522)	(31,846)
Other, net	(1,564)	(63)	0
Net cash provided by (used for) financing activities	234,662	(338,183)	(265,128)
Net increase (decrease) in cash and cash equivalents and restricted cash	923,507	230,102	(102,242)
Cash and cash equivalents and restricted cash at beginning of year	274,506	44,404	146,646
Cash and cash equivalents and restricted cash at end of year	$ 1,198,013	$ 274,506	$ 44,404