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Significant Accounting Policies and US GAAP (Details) | 6 Months Ended
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Jun. 30, 2012
Stock-based Compensation [Abstract] |  |
Restricted stock units vesting period (minimum) | 1 year |
Minimum [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful lives | 3 years |
Maximum [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Estimated useful lives | 5 years |
Vista Gold U.S., Inc. and its subsidiary [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Vista California, LLC [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Granges Inc. [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Desarrollos Zapal Holding Corp. and its subsidiaries [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Desarrollos Zapal S.A. de C.V. (1% owned by Granges Inc.) and its subsidiaries [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 99.00% | [1]
Voting rights in subsidiary held solely by reporting entity (in hundredths) | 37.50% |
Voting rights in subsidiary that are held in trust (in hundredths) | 62.50% |
Desarrollos Zapal S.A. de C.V. (1% owned by Granges Inc.) and its subsidiaries [Member] | Granges Inc. [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage by noncontrolling owners (in hundredths) | 1.00% |
Desarrollos Zapal S.A. de C.V. (1% owned by Granges Inc.) and its subsidiaries [Member] | Invecture Group, S.A. de C.V. [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Adjusted percentage interest to be earned by Invecture under earn-in agreement (in hundredths) | 62.50% |
Servicios Administrativos MPA S.A. de C.V. (1% owned by Granges Inc.) [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 99.00% |
Servicios Administrativos MPA S.A. de C.V. (1% owned by Granges Inc.) [Member] | Granges Inc. [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage by noncontrolling owners (in hundredths) | 1.00% |
Servicios Industriales MPA S.A. de C.V. (1% owned by Granges Inc.) [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 99.00% |
Servicios Industriales MPA S.A. de C.V. (1% owned by Granges Inc.) [Member] | Granges Inc. [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage by noncontrolling owners (in hundredths) | 1.00% |
Vista Gold (Barbados) Corp. and its wholly-owned subsidiary [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Salu Siwa Pty. Ltd and its subsidiary [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
PT Masmindo Dwi (1% owned by Vista Gold (Barbados) Corp.) [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 99.00% |
PT Masmindo Dwi (1% owned by Vista Gold (Barbados) Corp.) [Member] | Vista Gold (Barbados) Corp. and its wholly-owned subsidiary [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage by noncontrolling owners (in hundredths) | 1.00% |
Vista Minerals (Barbados) Corp. and its wholly-owned subsidiary [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Vista Gold Australia Pty Ltd. [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Minera Gold Stake Holdings Corp. (name changed from Vitliq Holdings Corp. effective January 23, 2012) [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 100.00% |
Minera Gold Stake S.A. de C.V. (name changed from Vitliq S.A. de C.V. effective January 23, 2012) (1% owned by Granges Inc.) [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage in subsidiary (in hundredths) | 99.00% |
Minera Gold Stake S.A. de C.V. (name changed from Vitliq S.A. de C.V. effective January 23, 2012) (1% owned by Granges Inc.) [Member] | Granges Inc. [Member] |  |
Subsidiaries and Percentage Ownership in Subsidiaries [Line Items] |  |
Ownership percentage by noncontrolling owners (in hundredths) | 1.00% |
[1] | On February 7, 2012, we entered into an earn-in right agreement (the "Earn-in Right Agreement") with Invecture Group, S.A de C.V. ("Invecture") whereby Invecture has the right, exercisable by February 7, 2014 (subject to extension) (the "Earn-in Right Period"), to earn a 62.5% interest in the Concordia gold project, which is owned through our wholly-owned, Mexican subsidiary, Desasarrollos Zapal, S.A. de C.V. ("DZ Mexico"). During the Earn-in Right Period and subject to the terms of the Earn-in Right Agreement, Vista holds 37.5% of the DZ Mexico shareholder voting rights. The remaining 62.5% of the DZ Mexico shareholder voting rights are held in a trust that is instructed by representatives of Vista and Invecture. Upon Invecture's exercise of the earn-in right, Vista will continue to hold a 37.5% interest in DZ Mexico and the Concordia gold project. See Note 5 for further discussion.

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