Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:
Net income (loss)	$ (25,130)	$ 14,954	$ 151,164
Non-cash elements included in net income (loss):
Depreciation, depletion and amortization	82,366	50,113	47,348
Net gain on sale of investments	(197)		(611)
Unrealized loss on investments	2,639	1,171	140
(Gain) loss on disposition of properties, plants, equipment and mineral interests	(75)	275
Provision for reclamation and closure costs	1,788	1,106	7,004
Deferred income taxes	(5,893)	546	76,944
Stock compensation	4,461	3,101	2,073
Amortization of loan origination fees	1,435	460	598
(Gain) loss on derivative contracts	(1,338)	29,627	(53,545)
Reversal of purchase price allocation to product inventory	550
Other non-cash items	(841)	1,765	1,209
Change in assets and liabilities, net of business acquired:
Accounts receivable	(1,313)	(4,713)	16,531
Inventories	(6,507)	(2,442)	(7,064)
Other current and non-current assets	3,281	610	2,164
Accounts payable and accrued liabilities	(10,927)	4,927	1,466
Accrued payroll and related benefits	539	(2,118)	2,090
Accrued taxes	(4,775)	1,967	(5,688)
Accrued reclamation and closure costs and other non-current liabilities	(13,418)	(32,333)	(171,932)
Net cash provided by operating activities	26,644	69,016	69,891
Investing activities:
Additions to properties, plants, equipment and mineral interests	(150,736)	(113,096)	(87,546)
Proceeds from sale of investments	1,772		1,366
Proceeds from disposition of properties, plants and equipment	460	886	113
Redemptions of restricted cash and investment balances			9,448
Increases in restricted cash and investment balances	125	(5)	(3,200)
Purchases of investments	(6,001)	(5,823)
Acquisition of Aurizon, net of cash acquired	(321,117)
Net cash used by investing activities	(475,497)	(118,038)	(79,819)
Financing activities:
Proceeds from exercise of warrants and stock options	61		5,786
Dividends paid to common stockholders	(5,991)	(17,121)	(5,592)
Dividend paid to preferred stockholders	(552)	(552)	(3,822)
Debt issuance and loan origination fees paid	(1,244)	(750)	(180)
Acquisition of treasury shares	(286)	(2,144)	(469)
Borrowings on debt	490,000
Repayments of capital leases	(7,039)	(5,890)	(2,938)
Net cash provided by (used in) financing activities	474,949	(26,457)	(7,215)
Effect of exchange rates on cash	(4,905)
Net increase (decrease) in cash and cash equivalents	21,191	(75,479)	(17,143)
Cash and cash equivalents at beginning of year	190,984	266,463	283,606
Cash and cash equivalents at end of year	212,175	190,984	266,463
Cash received (paid) during year for:
Interest	(13,465)	(1,968)	(1,683)
Income tax receipts (payments)	(1,402)	4,483	(17,874)
Significant non-cash investing and financing activities:
Stock issued for acquisition of assets	218,302		33,831
Capital leases acquired	12,344	13,119	6,935
Accounts payable change relating to capital additions	$ (7,067)	$ 3,727	$ 8,687