Future Share-Based Compensation Expense

No definition available.

Name:	gss_FutureShareBasedCompensationExpense
Namespace Prefix:	gss_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Share-Based Compensation Arrangement By Share-Based Payment Award, Award Requisite Service Period2

+ References

No definition available.

+ Details

Name:	gss_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod2
Namespace Prefix:	gss_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Share-Based Compensation Arrangement By Share-Based Payment Award, Conversion Ratio

+ References

No definition available.

+ Details

Name:	gss_ShareBasedCompensationArrangementByShareBasedPaymentAwardConversionRatio
Namespace Prefix:	gss_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights, Percentage1

+ References

No definition available.

+ Details

Name:	gss_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage1
Namespace Prefix:	gss_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant1

+ References

No definition available.

+ Details

Name:	gss_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesAvailableforGrant1
Namespace Prefix:	gss_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of expense arising from share-based payment transactions in which the goods or services received did not qualify for recognition as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2017-01-01
-Paragraph 51
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_51_a&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_ExpenseFromSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of liabilities arising from share-based payment transactions. Share-based payment transactions are transactions in which the entity: (a) receives goods or services from the supplier of those goods or services (including an employee) in a share-based payment arrangement; or (b) incurs an obligation to settle the transaction with the supplier in a share-based payment arrangement when another group entity receives those goods or services. [Refer: Share-based payment arrangements [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2017-01-01
-Paragraph 51
-Subparagraph b
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_51_b_i&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_LiabilitiesFromSharebasedPaymentTransactions2011
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of shares authorised.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 79
-Subparagraph a
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_79_a_i&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_NumberOfSharesAuthorised
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares issued by the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 106
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_106_d&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_NumberOfSharesIssued
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of current liabilities that the entity does not separately disclose in the same statement or note. [Refer: Current liabilities]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_55&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_OtherCurrentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of non-current liabilities that the entity does not separately disclose in the same statement or note. [Refer: Non-current liabilities]

+ References

+ Details

Name:	ifrs-full_OtherNoncurrentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The weighted average share price used as input to the option pricing model to calculate the fair value of share options granted. [Refer: Option pricing model [member]; Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2017-01-01
-Paragraph 47
-Subparagraph a
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2017-03-01&anchor=para_47_a_i&doctype=Standard
-URIDate 2017-03-09

+ Details

Name:	ifrs-full_WeightedAverageSharePriceShareOptionsGranted
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=gss_ShareAppreciationRightsSARMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=gss_PerformanceShareUnitsPSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=gss_PerformanceRestrictedShareUnitsPRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ComponentsOfEquityAxis=ifrs-full_SharePremiumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

SHARE-BASED COMPENSATION - Additional information (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Mar. 21, 2017 shares	May 05, 2016 shares	Dec. 31, 2015 shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of shares authorised (in shares) \| shares	35,000,000			10,000,000	25,000,000
Number of shares available for grant (in shares) \| shares	10,572,586	11,107,216
Weighted average fair value per option granted (usd per share)	$ 0.84	$ 0.35
Future share-based compensation expense	500,000	300,000
Other non-current liabilities	6,786,000	10,465,000
Other current liabilities	13,498,000	2,073,000
Share appreciation rights
Disclosure of terms and conditions of share-based payment arrangement [line items]
Unrecognized share-based compensation expense	400,000	$ 300,000
Performance share units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based compensation expense	$ 10,100,000
Share conversion ratio	1
Award requisite service period	3 years
Performance restricted share units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of shares issued (in shares) \| shares			1,694,491
Share conversion ratio	1
Award requisite service period	3 years
Minimum \| Performance share units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Award performance adjusting factor	0.00%
Minimum \| Performance restricted share units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Award performance adjusting factor	0.00%
Maximum \| Performance share units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Award performance adjusting factor	200.00%
Maximum \| Performance restricted share units
Disclosure of terms and conditions of share-based payment arrangement [line items]
Award performance adjusting factor	200.00%
Contributed Surplus
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based compensation expense	$ 334,000