Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities:
Net income	$ 102,430	$ 152,321
Discontinued operations, net of tax	65	34
Income from continuing operations	102,365	152,287
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	164,880	147,384
Deferred income taxes	1,464	14,498
Provision for credit losses	2,244	(1,158)
Amortization of debt issuance costs	709	633
Employee stock-based compensation costs	5,378	8,724
Pension and postretirement benefit plan net periodic benefit credit	(3,004)	(2,457)
Unrealized (gains) losses on investments	13,210	(3,795)
Gains on sales of assets	(5,434)	(8,021)
Changes in current assets and liabilities, net of acquisitions:
Receivables	(242,252)	(17,358)
Inventories	(63,840)	(25,330)
Other current assets	12,888	(52,768)
Accounts payable	104,451	(3,845)
Other current liabilities	29,178	(22,605)
Pension and postretirement benefit plan contributions	(262)	(225)
Other noncurrent changes	(4,509)	(3,095)
Net cash provided by continuing operations	117,466	182,869
Net cash used in discontinued operations	(16)	(58)
Net cash provided by operating activities	117,450	182,811
Investing activities:
Capital expenditures	(290,145)	(261,937)
Acquisitions, net of cash acquired	(524)	(13,721)
Net proceeds from sale or disposition of property and other	4,324	12,402
Investments	(4,680)	(3,244)
Net cash used in investing activities	(291,025)	(266,500)
Financing activities:
Issuance of short-term borrowings	100,000	50,000
Repayment of short-term borrowings	0	(50,000)
Issuance of long-term debt	334,329	171,774
Repayment of long-term debt	(147,544)	(48,151)
Debt issuance costs	(1,068)	(5)
Net proceeds from issuance of common stock	(149)	54,649
Dividends paid	(88,457)	(85,351)
Repurchase of common stock	(7,399)	(6,701)
Tax withholding on stock-based compensation	(4,904)	(4,127)
Net cash provided by financing activities	184,808	82,088
Increase (decrease) in cash and cash equivalents	11,233	(1,601)
Cash and cash equivalents -- beginning of year	54,161	59,547
Cash and cash equivalents -- end of period	$ 65,394	$ 57,946