Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating activities:
Net income	$ 243,974	$ 250,401
Discontinued operations, net of tax	(65,752)	103,504
Income from continuing operations	309,726	146,897
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	158,877	158,622
Deferred income taxes	63,745	13,697
Provision for credit losses	9,769	3,554
Amortization of debt issuance costs	991	725
Employee stock-based compensation costs	3,943	5,689
Pension and postretirement benefit plan net periodic benefit credit	(4,086)	(5,494)
Unrealized Gain (Loss) on investment in Knife River	(170,170)	0
Unrealized (gains) losses on investments	(3,501)	12,357
Gains on sales of assets	(6,761)	(4,925)
Changes in current assets and liabilities, net of acquisitions:
Receivables	161,366	(107,314)
Inventories	(19,694)	(43,649)
Other current assets	(68,161)	(32,241)
Accounts payable	(132,323)	89,876
Other current liabilities	42,310	40,931
Pension and postretirement benefit plan contributions	(7,541)	(62)
Other noncurrent changes	(3,362)	(24,981)
Net cash provided by continuing operations	335,128	253,682
Net cash provided by (used in) discontinued operations	(160,214)	31,251
Net cash provided by operating activities	174,914	284,933
Investing activities:
Capital expenditures	(370,585)	(341,162)
Net proceeds from sale or disposition of property and other	13,238	(4,101)
Investments	(3,339)	(2,185)
Net Cash Provided by (Used in) Investing Activities, Continuing Operations	(360,686)	(347,448)
Cash Provided by (Used in) Investing Activities, Discontinued Operations	(55,012)	(117,900)
Net cash used in investing activities	(415,698)	(465,348)
Financing activities:
Issuance of short-term borrowings	461,400	0
Repayment of short-term borrowings	(193,500)	0
Issuance of long-term debt	411,900	220,429
Repayment of long-term debt	(434,994)	0
Debt issuance costs	(1,844)	(334)
Net proceeds from issuance of common stock	0	(149)
Dividends paid	(135,861)	(132,687)
Repurchase of common stock	(4,811)	(7,399)
Tax withholding on stock-based compensation	(3,040)	(4,904)
Net Cash Provided by (Used in) Financing Activities, Continuing Operations	99,250	74,956
Cash Provided by (Used in) Financing Activities, Discontinued Operations	93,509	125,918
Net Cash Provided by (Used in) Financing Activities, Total	192,759	200,874
Increase (decrease) in cash and cash equivalents	(48,025)	20,459
Cash and cash equivalents -- beginning of year	80,518	54,161
Cash and cash equivalents -- end of period	$ 32,493	$ 74,620