XML 159 R110.htm IDEA: XBRL DOCUMENT
v3.20.1

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Income Taxes [abstract] |  |
Applicable tax rate | 27.00% | 27.00%
Resource related expense accumulated with no deferred tax benefit recognized | $ 8,188 | $ 6,582

X
- Definition Income Taxes [abstract]. + References No definition available. + Details
Name: | fsm_IncomeTaxesAbstract
Namespace Prefix: | fsm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Resource related expense accumulated with no deferred tax benefit recognized. + References No definition available. + Details
Name: | fsm_ResourceRelatedExpenseAccumulatedWithNoDeferredTaxBenefitRecognized
Namespace Prefix: | fsm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The applicable income tax rate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 12 -IssueDate 2018-01-01 -Paragraph 81 -Subparagraph c -Clause ii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_c_ii&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_ApplicableTaxRate
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration