XML 132 R115.htm IDEA: XBRL DOCUMENT v3.19.1

Other financial Liabilities - Interest rate swaps (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other financial liabilities
Valuation adjustments reserve related to hedging relationship for which hedge accounting no longer applied	$ 2,602
Market value	(3,079)	$ (4,392)
Derivatives [member]
Other financial liabilities
Nominal Amount	23,463	38,040
Later Than Six Years And Not Later Seven Years [Member] | Lease Of Hydroelectrical Installations [Member]
Other financial liabilities
Nominal Amount		$ 143,916
Fixed Interest Rate		2.05%
Reference Floating Interest Rate		6-month Euribor
Market value	(3,079)	$ (4,392)
Later Than Six Years And Not Later Seven Years [Member] | Lease Of Hydroelectrical Installations [Member] | Fixed rate
Other financial liabilities
Nominal Amount	$ 137,400
Fixed Interest Rate	2.05%
Reference Floating Interest Rate	6-month Euribor

X

- Definition

The interest rate on borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2018-01-01
-Paragraph 7
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_7&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_BorrowingsInterestRate
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The basis (reference rate) used for calculation of the interest rate on borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2018-01-01
-Paragraph 7
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_7&doctype=Standard
-URIDate 2018-03-16

+ Details

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

X

- References

No definition available.

+ Details

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

X

- Definition

The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2018-01-01
-Paragraph 25
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_25&doctype=Standard
-URIDate 2018-03-16

+ Details

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

X

- Definition

The nominal or face amount of a financial instrument, used to calculate payments made on that instrument.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_NotionalAmount
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

A component of equity representing the reserve of cash flow hedges in relation to hedging relationships for which hedge accounting is no longer applied. [Refer: Reserve of cash flow hedges]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2018-01-01
-Paragraph 24B
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2018-03-01&anchor=para_24B_b_iii&doctype=Standard
-URIDate 2018-03-16

+ Details

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

X

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=ifrs-full_DerivativesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_MaturityAxis=gsm_LaterThanSixYearsAndNotLaterSevenYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=gsm_LeaseOfHydroelectricalInstallationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_TypesOfInterestRatesAxis=ifrs-full_FixedInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: