Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net income	$ 439,453	$ 290,278
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	116,294	109,601
Provision for (recovery of) doubtful accounts	3,600	(536)
Amortization of debt issuance costs	1,093	1,149
Stock-based compensation expense	4,804	4,640
Loss from disposition of fixed assets	4,679	1,945
Gain from sales of equity securities	0	(16,429)
Write off of Deferred Debt Issuance Cost	0	1,277
Deferred income taxes	83,443	4,385
Windfall tax benefits from share-based payment arrangements	(5,056)	(7,792)
Equity in (income) loss of joint ventures	1,586	2,567
Changes in operating assets and liabilities
Accounts receivable	(18,874)	13,732
Inventories	(26,325)	119,240
Prepaid expenses and other current assets	(5,038)	(1,977)
Accounts payable	19,518	(35,651)
Accrued liabilities	(15,755)	20,077
Other, net	(55,922)	(13,675)
Net cash provided by operating activities	547,500	492,831
Cash flows from investing activities
Acquisition of business	(178,309)	0
Additions to equity investments	(23,338)	0
Additions to property, plant and equipment	(498,290)	(235,463)
Construction of assets pending sale-leaseback	(136)	(5,484)
Proceeds from disposition of assets	78	435
Proceeds from repayment of loan to affiliate	167	763
Proceeds from sale and maturities of securities	239,764	47,655
Purchase of securities and other investments	(232,286)	(2,961)
Settlements of derivative instruments	(2,297)	471
Net cash used for investing activities	(694,647)	(194,584)
Cash flows from financing activities
Capitalized debt issuance costs	0	(2,221)
Dividends paid	(40,204)	(22,345)
Proceeds from Issuance of Long-term Debt	0	248,818
Proceeds from exercise of stock options	3,182	6,627
Repayments of Long-term Debt	0	250,000
Repurchase of common stock for treasury	(19,409)	(10,784)
Utilization of restricted cash	0	96,433
Windfall tax benefits from share-based payment arrangements	5,056	7,792
Net cash provided by financing activities	(51,375)	74,320
Net increase in cash and cash equivalents	(198,522)	372,567
Cash and cash equivalents at beginning of period	790,078	825,901
Cash and cash equivalents at end of period	$ 591,556	$ 1,198,468