CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities
Net income	$ 203,314	$ 164,593
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	71,177	65,383
(Recovery of) provision for doubtful accounts	(161)	811
Amortization of debt issue costs	801	863
Stock-based compensation expense	3,125	3,127
Loss from disposition of fixed assets	688	142
Gain from sales of equity securities	(15,952)
Impairment of long-lived assets		1,975
Deferred income taxes	6,720	15,949
Equity in loss (income) of joint ventures	1,926	(1,552)
Changes in operating assets and liabilities
Accounts receivable	(11,105)	(68,249)
Inventories	83,653	(58,170)
Prepaid expenses and other current assets	(2,920)	(4,928)
Accounts payable	(17,043)	19,362
Accrued liabilities	(6,369)	(12,506)
Other, net	4,760	(1,495)
Net cash (used for) provided by operating activities	322,614	125,305
Cash flows from investing activities
Additions to property, plant and equipment	(140,568)	(69,178)
Construction of assets pending sale-leaseback	(1,760)
Proceeds from disposition of assets	415	2,456
Proceeds from repayment of loan to affiliate	596	596
Proceeds from sales of equity securities	46,027
Purchase of investments	(2,961)
Settlements of derivative instruments	511	(222)
Net cash used for investing activities	(97,740)	(66,348)
Cash flows from financing activities
Capitalized debt issuance costs	(98)
Dividends paid	(9,838)	(8,446)
Proceeds from exercise of stock options	4,508	5,323
Repurchase of common stock for treasury	(10,784)
Utilization of restricted cash	75,975	26,189
Net cash provided by (used for) financing activities	59,763	23,066
Net increase in cash and cash equivalents	284,637	82,023
Cash and cash equivalents at beginning of period	825,901	630,299
Cash and cash equivalents at end of period	$ 1,110,538	$ 712,322