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Significant Accounting Policies and US GAAP (Details)	6 Months Ended
	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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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Adjusted percentage of interest to be earned by a third party investor under an agreement for a certain project.

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The equity voting rights in the subsidiary that are held solely by the reporting entity.

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The equity voting rights in the subsidiary that are held in a trust that is instructed by representatives of the reporting entity and a third party investor.

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