CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
OPERATING ACTIVITIES
Net income	$ 283,687us-gaap_ProfitLoss	$ 324,597us-gaap_ProfitLoss
Adjustments to reconcile net income to net cash provided from operating activities:
Depreciation, amortization and depletion	116,963	110,453
Equity earnings of affiliate, net of dividends received	(490)	(3,414)
(Gain) loss on currency translation effect	(10,953)	(5,688)
(Benefit) provision for deferred income taxes	(24,698)us-gaap_DeferredIncomeTaxExpenseBenefit	(84,320)us-gaap_DeferredIncomeTaxExpenseBenefit
Other, net	229us-gaap_OtherNoncashIncomeExpense
Change in operating assets and liabilities:
Decrease (increase) in accounts receivable	39,050	(10,074)
(Increase) decrease in inventories	(54,699)us-gaap_IncreaseDecreaseInInventories	(102,061)us-gaap_IncreaseDecreaseInInventories
Increase (decrease) in accounts payable and accrued liabilities	(180,571)	69,313
Increase (decrease) in other operating assets and liabilities	52,949	49,429
Net cash provided from operating activities	221,467	348,235
INVESTING ACTIVITIES
Capital investments	(245,832)	(336,928)
Proceeds from (purchase of) short-term investments, net	254,769	(64,742)
Sale of property		294
Net cash provided by (used in) investing activities	8,937	(401,376)
FINANCING ACTIVITIES
Debt incurred	50,000
Cash dividends paid to common stockholders	(80,486)us-gaap_PaymentsOfDividendsCommonStock	(100,026)us-gaap_PaymentsOfDividendsCommonStock
Repurchase of common shares	(370,103)	(52,479)
Distributions to non-controlling interest	(195)	(302)
Net cash used in financing activities	(400,784)	(152,807)
Effect of exchange rate changes on cash and cash equivalents	(1,452)	6,354
Net (decrease) in cash and cash equivalents	(171,832)	(199,594)
Cash and cash equivalents at beginning of year	363,970	1,672,695
Cash and cash equivalents at end of year	$ 192,138	$ 1,473,101

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