Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash Flows from Operating Activities:
Consolidated net earnings	$ 326,647	$ 205,715
Adjustments to reconcile consolidated net earnings to net cash provided by operating activities:
Depreciation, depletion and amortization	211,997	199,935
Stock-based compensation expense	17,167	10,722
Loss on divestitures and sales of assets	158	27,568
Deferred income taxes	59,834	43,286
Excess tax benefits from stock-based compensation transactions	(5,010)
Other items, net	(17,797)	(6,554)
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable, net	(133,848)	(155,054)
Inventories, net	(33,956)	(17,650)
Accounts payable	12,422	22,186
Other assets and liabilities, net	(23,546)	(10,575)
Net Cash Provided by Operating Activities	414,068	319,579
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(285,481)	(212,447)
Acquisitions, net	(178,689)	(10,748)
Cash received in acquisition	4,246
Proceeds from divestitures and sales of assets	5,216	422,045
Repayments from affiliate		1,808
Payment of railcar construction advances	(37,370)	(25,341)
Reimbursement of railcar construction advances	37,370	25,234
Net Cash (Used for) Provided by Investing Activities	(454,708)	200,551
Cash Flows from Financing Activities:
Borrowings of debt	360,000	230,000
Repayments of debt	(168,267)	(111,384)
Payments on capital lease obligations	(2,463)	(5,784)
Debt issuance costs	(213)
Change in bank overdraft	(10,235)	(183)
Dividends paid	(78,295)	(81,219)
Issuances of common stock	17,378	33,892
Repurchases of common stock	(190,000)	(257,674)
Excess tax benefits from stock-based compensation transactions	5,010
Net Cash Used for Financing Activities	(67,085)	(192,352)
Net (Decrease) Increase in Cash and Cash Equivalents	(107,725)	327,778
Cash and Cash Equivalents, beginning of period	168,409	108,651
Cash and Cash Equivalents, end of period	60,684	436,429
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest	48,813	47,069
Cash paid for income taxes	$ 81,589	$ 30,896