CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Reconciliation of net income to net cash provided by operating activities:
Net income	$ 84,494	$ 27,108
Deferred income taxes	42,614	19,355
Insurance settlements from property and business losses	(12,500)
Items not affecting cash:
Depreciation, depletion, amortization, and accretion	26,043	20,086
Stock-based compensation	3,776	3,093
Unrealized derivative gain	(913)	(173)
Other	1,565	756
Changes in operating assets and liabilities:
Trade accounts receivable	(10,395)	(17,870)
Other receivables	(9,834)	(1,401)
Refundable income taxes	(552)	3,074
Inventory	(6,996)	15,808
Prepaid expenses and other assets	(541)	(2,309)
Accounts payable, accrued liabilities and accrued employee compensation and benefits	13,243	10,365
Other liabilities	(392)	(1,383)
Net cash provided by operating activities	129,612	76,509
Cash Flows from Investing Activities:
Additions to property, plant, and equipment	(100,936)	(57,844)
Additions to mineral properties and development costs	(780)	(222)
Proceeds from insurance settlements from property and business losses	806	1,576
Purchases of investments	(78,360)	(61,909)
Proceeds from investments	42,779	19,498
Net cash used in investing activities	(136,491)	(98,901)
Cash Flows from Financing Activities:
Debt issuance costs	(1,454)
Employee tax withholding paid for restricted stock upon vesting	(1,077)	(727)
Excess income tax benefit from stock-based compensation	434
Proceeds from exercise of stock options	330	19
Net cash used in financing activities	(1,767)	(708)
Net Change in Cash and Cash Equivalents	(8,646)	(23,100)
Cash and Cash Equivalents, beginning of period	76,133	89,792
Cash and Cash Equivalents, end of period	67,487	66,692
Cash paid (received) during the period for:
Interest, including settlements on derivatives	1,165	1,574
Income taxes	$ 12,983	$ (4,008)

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The aggregate net amount of depreciation, depletion, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by (used in) operations using the indirect method.