Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities:
Consolidated net earnings	$ 480,918	$ 375,896
Adjustments to reconcile consolidated net earnings to net cash provided by operating activities:
Depreciation, depletion and amortization	276,974	253,200
Stock-based compensation expense	28,414	23,084
Gain on divestitures and sales of assets	(4,950)	(35,167)
Deferred income taxes	18,352	68,833
Other items, net	11,422	(2,107)
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable, net	(240,602)	(132,176)
Inventories, net	13,573	(8,015)
Accounts payable	65,897	42,995
Other assets and liabilities, net	(200)	(145,005)
Net Cash Provided by Operating Activities	649,798	441,538
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(282,998)	(262,155)
Acquisitions, net		(1,640,698)
Proceeds from divestitures and sales of assets	6,981	63,460
Payment of railcar construction advances		(56,033)
Reimbursement of railcar construction advances		56,033
Investments in life insurance contracts, net	559	771
Other investing activities, net	(1,214)
Net Cash Used for Investing Activities	(276,672)	(1,838,622)
Cash Flows from Financing Activities:
Borrowings of debt	245,000	875,000
Repayments of debt	(445,042)	(695,039)
Payments of deferred acquisition consideration		(6,707)
Payments on financing leases	(2,651)
Payments on capital leases		(2,589)
Debt issuance costs		(3,194)
Distributions to owners of noncontrolling interest	(600)
Repurchases of common stock	(57,288)	(60,377)
Dividends paid	(95,227)	(86,190)
Proceeds from exercise of stock options	12,295	6,993
Shares withheld for employees' income tax obligations	(25,418)	(10,416)
Purchase of remaining interest in existing joint venture		(12,800)
Net Cash (Used for) Provided by Financing Activities	(368,931)	4,681
Net Increase (Decrease) in Cash and Cash Equivalents	4,195	(1,392,403)
Cash and Cash Equivalents, beginning of period	44,892	1,446,364
Cash and Cash Equivalents, end of period	$ 49,087	$ 53,961