Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities:
Net income	$ 250,401	$ 291,597
Discontinued operations, net of tax	103	348
Income from continuing operations	250,298	291,249
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	247,173	222,613
Deferred income taxes	18,741	30,353
Provision for credit losses	3,258	(801)
Amortization of debt issuance costs	1,080	997
Employee stock-based compensation costs	6,488	11,649
Pension and postretirement benefit plan net periodic benefit credit	(4,515)	(3,690)
Unrealized (gains) losses on investments	15,529	(4,408)
Gains on sales of assets	(8,500)	(10,518)
Changes in current assets and liabilities, net of acquisitions:
Receivables	(346,879)	(103,637)
Inventories	(60,670)	(21,402)
Other current assets	(31,405)	(74,413)
Accounts payable	148,456	33,173
Other current liabilities	62,106	14,175
Pension and postretirement benefit plan contributions	(375)	(326)
Other noncurrent changes	(15,835)	(19,129)
Net cash provided by continuing operations	284,950	365,885
Net cash used in discontinued operations	(17)	(75)
Net cash provided by operating activities	284,933	365,810
Investing activities:
Capital expenditures	(463,002)	(428,114)
Acquisitions, net of cash acquired	450	(13,721)
Net proceeds from sale or disposition of property and other	1,615	12,954
Investments	(4,411)	(3,777)
Net cash used in investing activities	(465,348)	(432,658)
Financing activities:
Issuance of short-term borrowings	100,000	50,000
Repayment of short-term borrowings	0	(50,000)
Issuance of long-term debt	270,250	178,879
Repayment of long-term debt	(23,155)	(63,835)
Debt issuance costs	(1,082)	(362)
Net proceeds from issuance of common stock	(149)	88,830
Dividends paid	(132,687)	(128,142)
Repurchase of common stock	(7,399)	(6,701)
Tax withholding on stock-based compensation	(4,904)	(4,127)
Net cash provided by financing activities	200,874	64,542
Increase (decrease) in cash and cash equivalents	20,459	(2,306)
Cash and cash equivalents -- beginning of year	54,161	59,547
Cash and cash equivalents -- end of period	$ 74,620	$ 57,241