CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 12,380	$ 24,321
Investments (note 4)	1,082	2
Value added taxes receivable	11,739us-gaap_ValueAddedTaxReceivableCurrent	11,591us-gaap_ValueAddedTaxReceivableCurrent
Inventories (note 5)	12,404us-gaap_InventoryNet	8,800us-gaap_InventoryNet
Other current assets	2,096us-gaap_OtherAssetsCurrent	2,057us-gaap_OtherAssetsCurrent
Total current assets	39,701us-gaap_AssetsCurrent	46,771us-gaap_AssetsCurrent
Mineral property interests (note 6)	287,812us-gaap_MineralPropertiesNet	642,968us-gaap_MineralPropertiesNet
Restricted time deposits for reclamation bonding (note 6)		5,183
Investment in Minera Santa Cruz S.A. (note 7)	177,018	212,947
Property and equipment, net (note 8)	17,896us-gaap_PropertyPlantAndEquipmentNet	15,143us-gaap_PropertyPlantAndEquipmentNet
Other assets	531us-gaap_OtherAssetsNoncurrent	54us-gaap_OtherAssetsNoncurrent
TOTAL ASSETS	522,958us-gaap_Assets	923,066us-gaap_Assets
Current liabilities:
Accounts payable and accrued liabilities	21,654	9,797
Current portion of asset retirement obligation (note 6)	2,427	1,392
Total current liabilities	24,081us-gaap_LiabilitiesCurrent	11,189us-gaap_LiabilitiesCurrent
Asset retirement obligation, less current portion (note 6)	5,044	5,855
Deferred income tax liability (note 9)	51,899us-gaap_DeferredTaxLiabilities	158,855us-gaap_DeferredTaxLiabilities
Deferred rent expenses	319us-gaap_DeferredRentCreditNoncurrent
Other liabilities	400us-gaap_OtherLiabilitiesNoncurrent	400us-gaap_OtherLiabilitiesNoncurrent
Total liabilities	81,743us-gaap_Liabilities	176,299us-gaap_Liabilities
Shareholders' equity:
Common stock, no par value, 500,000 shares authorized; Common: 271,579 as of December 31, 2014 and 264,913 shares as of December 31, 2013 issued and outstanding Exchangeable: 28,521 shares as of December 31, 2014 and 32,246 shares as of December 31, 2013 issued and outstanding	1,360,668us-gaap_CommonStockValue	1,354,696us-gaap_CommonStockValue
Accumulated deficit	(919,577)	(607,634)
Accumulated other comprehensive income (loss)	124	(295)
Total shareholders' equity	441,215us-gaap_StockholdersEquity	746,767us-gaap_StockholdersEquity
TOTAL LIABILITIES & SHAREHOLDERS' EQUITY	522,958	923,066
Commitments and Contingencies (note 13)

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant