Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities:
Net income	$ 151,164	$ 48,983	$ 67,826
Non-cash elements included in net income:
Depreciation, depletion and amortization	47,348	60,235	63,061
Net gain on sale of investments	(611)	(588)	(4,070)
Loss on impairment of investments	140	739	3,018
Loss (gain) on disposition of properties, plants, equipment and mineral interests		80	(6,234)
Provision for reclamation and closure costs	7,004	196,262	5,172
Deferred income taxes	76,944	(141,707)	(7,100)
Stock compensation	2,073	3,446	2,746
Preferred shares issued for debt-related fees			4,262
Amortization of loan origination fees	598	621	3,993
Amortization of intangible asset		1,380	1,388
Gain on termination of employee benefit plan			(8,950)
(Gain) loss on derivative contracts	(53,545)	20,795	2,139
Other non-cash items	1,209	(495)	(55)
Change in assets and liabilities:
Accounts receivable	16,531	(9,404)	(18,117)
Inventories	(7,064)	2,335	(135)
Other current and noncurrent assets	2,164	3,279	(1,526)
Accounts payable and accrued liabilities	1,466	10,896	(3,663)
Accrued payroll and related benefits	2,090	(3,376)	6,015
Accrued taxes	(5,688)	9,802	4,866
Accrued reclamation and closure costs	(172,855)	(8,666)	1,540
Other non-current liabilities	923	3,192	2,989
Net cash provided by operating activities	69,891	197,809	119,165
Investing activities:
Additions to properties, plants, equipment and mineral interests	(87,546)	(67,414)	(27,704)
Proceeds from sale of investments	1,366	1,138	4,091
Proceeds from disposition of properties, plants and equipment	113	29	8,023
Redemptions of restricted cash and investment balances	9,448	1,459	3,487
Increases in restricted cash and investment balances	(3,200)
Net cash used by investing activities	(79,819)	(64,788)	(12,103)
Financing activities:
Proceeds from exercise of warrants and stock options	5,786	53,093
Proceeds from issuance of common stock and warrants, net of related expense			128,334
Dividends paid to common shareholders	(5,592)
Dividend paid to preferred shareholders	(3,822)	(4,513)
Loan origination fees paid	(180)	(200)	(1,467)
Payments on interest rate swap			(3,013)
Treasury share purchase	(469)	(693)
Repayments of debt and capital leases	(2,938)	(1,780)	(162,708)
Net cash provided by (used in) financing activities	(7,215)	45,907	(38,854)
Net increase (decrease) in cash and cash equivalents	(17,143)	178,928	68,208
Cash and cash equivalents at beginning of year	283,606	104,678	36,470
Cash and cash equivalents at end of year	266,463	283,606	104,678
Cash paid during year for:
Interest, net of amount capitalized	1,683	584	6,683
Income tax payments	17,874	11,075	1,025
Significant non-cash investing and financing activities:
Stock issued for acquisition of assets	33,831
Capital leases acquired	6,935	3,212	5,682
Equity securities received from dispositions of assets			299
Accounts payable change relating to capital additions	8,687	3,488	(4,190)
Preferred stock dividends paid in common stock		$ 22,891