Organization and Subsidiaries (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Organization and Subsidiaries [Abstract]

Schedule of subsidiaries by business activity

	Percentage of Ownership
	Direct	Total	Line of Business	Registered
Alabama Sand and Gravel, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
Alden Resources, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
Alden Sales Corporation, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
ARL Resources, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
ARL Services, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
Core Metals Group Holdings, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
Core Metals Group, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
Gatliff Services, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
Globe Metallurgical Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
Globe Metals Enterprises, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
GSM Alloys I, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
GSM Alloys II, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
GSM Enterprises Holdings, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
GSM Enterprises, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
GSM Sales, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
LF Resources, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
Metallurgical Process Materials, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
Norchem, Inc.	—	100.0	Electrometallurgy - North America	Florida - USA
QSIP Canada ULC	—	100.0	Electrometallurgy - North America	Canada
Quebec Silicon General Partner	—	51.0	Electrometallurgy - North America	Canada
Quebec Silicon Limited Partnership	—	51.0	Electrometallurgy - North America	Canada
Tennessee Alloys Company, LLC	—	100.0	Electrometallurgy - North America	Delaware - USA
West Virginia Alloys, Inc.	—	100.0	Electrometallurgy - North America	Delaware - USA
WVA Manufacturing, LLC	—	51.0	Electrometallurgy - North America	Delaware - USA
Cuarzos Industriales, S.A.U.	—	100.0	Electrometallurgy - Europe	A Coruña - Spain
Ferroatlántica del Cinca, S.L.	—	99.9	Electrometallurgy - Europe	Madrid - Spain
Ferroatlántica de Sabón, S.L.U. (1)	—	100.0	Electrometallurgy - Europe	Madrid - Spain
Ferroatlántica de Boo, S.L.U. (1)	—	100.0	Electrometallurgy - Europe	Madrid - Spain
Ferroglobe Mangan Norge AS	—	100.0	Electrometallurgy - Europe	Norway
Ferroglobe Manganese France SAS	—	100.0	Electrometallurgy - Europe	France
FerroPem, S.A.S.	—	100.0	Electrometallurgy - Europe	France
Ferrous Receivables DAC. (1)	—	100.0	Electrometallurgy - Europe	Ireland
Grupo FerroAtlántica, S.A.U	100	100.0	Electrometallurgy - Europe	Madrid - Spain
Islenska Kisilfelagio EHF (Icelandic Silicon Corp.)	—	20.1	Electrometallurgy - Europe	Ireland
Kintuck (France) SAS	—	100.0	Electrometallurgy - Europe	France
Kintuck AS	—	100.0	Electrometallurgy - Europe	Norway
Rocas, Arcillas y Minerales, S.A.	—	100.0	Electrometallurgy - Europe	A Coruña - Spain
Rebone Mining (Pty.), Ltd.	—	74.0	Electrometallurgy - South Africa	Polokwane - South Africa
Silicon Smelters (Pty.), Ltd.	—	100.0	Electrometallurgy - South Africa	Polokwane - South Africa
Silicon Technology (Pty.), Ltd.	—	100.0	Electrometallurgy - South Africa	South Africa
Thaba Chueu Mining (Pty.), Ltd.	—	74.0	Electrometallurgy - South Africa	Polokwane - South Africa
16 Front Street, LLC	—	100.0	Other segments	Delaware - USA
Actifs Solaires Bécancour, Inc	—	100.0	Other segments	Canada
Cuarzos Indus. de Venezuela (Cuarzoven), S.A.	—	100.0	Other segments	Venezuela
Emix, S.A.S.	—	100.0	Other segments	France
ECPI, Inc.	—	100.0	Other segments	Delaware - USA
Ferroatlántica de México, S.A. de C.V.	—	100.0	Other segments	Nueva León - Mexico
Ferroatlántica de Venezuela (FerroVen), S.A.	—	99.9	Other segments	Venezuela
Ferroatlántica Deutschland, GmbH	—	100.0	Other segments	Germany
Ferroatlántica do Brasil Mineraçao Ltda.	—	70.0	Other segments	Brazil
Ferroatlántica I+D, S.L.U.	—	100.0	Other segments	Madrid - Spain
Ferroatlántica Participaciones, S.L.U.  (1)	—	100.0	Other segments	Madrid - Spain
FerroAtlántica International Ltd	—	100.0	Other segments	United Kingdom
Ferroglobe Services (UK) PLC	100	100.0	Other segments	United Kingdom
FerroManganese Mauritania SARL	—	90.0	Other segments	Mauritania
Ferroquartz Holdings, Ltd (Hong Kong)	—	100.0	Other segments	Hong Kong
FerroQuartz Mauritania SARL	—	90.0	Other segments	Mauritania
Ferrosolar OPCO Group SL.	—	100.0	Other segments	Spain
Ferrosolar R&D SL.	—	50.0	Other segments	Spain
FerroTambao, SARL	—	90.0	Other segments	Burkina Faso
GBG Financial LLC	—	100.0	Other segments	Delaware - USA
GBG Holdings, LLC	—	100.0	Other segments	Delaware - USA
Globe Argentina Holdco, LLC	—	100.0	Other segments	Delaware - USA
Globe BG, LLC	—	100.0	Other segments	Delaware - USA
Globe LSE, Inc.	—	100.0	Other segments	Delaware - USA
Globe Metales S.R.L.	—	100.0	Other segments	Argentina
Globe Metallurgical Carbon, LLC	—	100.0	Other segments	Delaware - USA
Globe Specialty Metals, Inc.	100	100.0	Other segments	Delaware - USA
Grupo FerroAtlántica de Servicios, S.L.U.  (1)	—	100.0	Other segments	Madrid - Spain
GSM Financial, Inc.	—	100.0	Other segments	Delaware - USA
GSM Netherlands, BV	—	100.0	Other segments	Netherlands
Hidroelectricité de Saint Beron, S.A.S  (1)	—	100.0	Other segments	France
Laurel Ford Resources, Inc.	—	100.0	Other segments	Delaware - USA
Mangshi FerroAtlántica Mining Indus. Serv. Ltd	—	100.0	Other segments	Mangshi, Dehong -Yunnan -China
Mangshi Sinice Silicon Industry Company Limited	—	100.0	Other segments	Mangshi, Dehong -Yunnan -China
MST Financial Holdings, LLC	—	100.0	Other segments	Delaware - USA
MST Financial, LLC	—	100.0	Other segments	Delaware - USA
MST Resources, LLC	—	100.0	Other segments	Delaware - USA
Ningxia Yonvey Coal Industrial Co., Ltd.	—	98.0	Other segments	China
Photosil Industries, SAS	—	100.0	Other segments	France
Silicio Ferrosolar, SLU	—	100.0	Other segments	Spain
Solsil, Inc.	—	92.4	Other segments	Delaware - USA
Ultracore Energy SA	—	100.0	Other segments	Argentina

(1) Entered into the scope of consolidation during 2019.