Aggregate amount of equipment orders.

No definition available.

Name:	gmo_AggregateAmountOfEquipmentOrders
Namespace Prefix:	gmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the commitments of the LLC, and as a result of the agreement between Nevada Moly and POS-Minerals are to be funded to reserve account until such time that the Company

+ References

No definition available.

+ Details

Name:	gmo_AmountFundedToReserveAccount
Namespace Prefix:	gmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of equipment orders relate to fully fabricated items.

+ References

No definition available.

+ Details

Name:	gmo_AmountOfEquipmentOrdersRelatedToFullyFabricatedItems
Namespace Prefix:	gmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of equipment orders relate to partially fabricated milling equipment and non-refundable deposits on mining equipment.

+ References

No definition available.

+ Details

Name:	gmo_AmountOfEquipmentOrdersRelatedToPartiallyFabricatedMillingEquipmentAndNonRefundableDeposits
Namespace Prefix:	gmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The remaining reserve balance from the initial fund from members.

+ References

No definition available.

+ Details

Name:	gmo_InitialFundFromMembersReserveAccountBalance
Namespace Prefix:	gmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents per month reduction in non-equipment related cash requirements.

+ References

No definition available.

+ Details

Name:	gmo_ReductionInNonEquipmentRelatedCashRequirementsPerMonth
Namespace Prefix:	gmo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow associated with the amount received from entity's raising of capital via private rather than public placement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3255-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

+ References

No definition available.

+ Details

Name:	us-gaap_PurchaseObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_CounterpartyNameAxis=gmo_AmerInternationalGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=us-gaap_PurchaseCommitmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gmo_NevadaMolyLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_CoVenturerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=gmo_MiningAndMillingEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gmo_EurekaMolyLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationByPropertyOrProjectAxis=gmo_MountHopeProjectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LIQUIDITY - Purchase Commitment excluding Long-term Commitment (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2015	Dec. 31, 2016	Dec. 31, 2015
Cash commitments
Amount committed to be purchased		$ 2.2
Per month reduction in non-equipment related cash requirements		1.5
AMER International Group
Cash commitments
Proceeds from equity investment		16.0
Purchase Commitment \| Nevada Moly LLC \| POS-Minerals Corporation
Cash commitments
Amount funded to reserve account		36.0
Purchase Commitment \| Mining and milling equipment \| Eureka Moly LLC
Cash commitments
Aggregate amount of equipment orders		87.2
Amount of equipment orders relate to fully fabricated items		70.4
Amount committed to be purchased		2.2
Amount of equipment orders relate to partially fabricated milling equipment, and non-refundable deposits on mining equipment		16.8
Purchase Commitment \| Mining and milling equipment \| Nevada Moly LLC \| POS-Minerals Corporation
Cash commitments
Amount funded to reserve account		36.0
Balance of reserve account		13.0
Mt. Hope Project
Cash commitments
Balance of reserve account		$ 13.0	$ 16.6
Mt. Hope Project \| Eureka Moly LLC
Cash commitments
Aggregate amount of equipment orders			$ 87.2
Mt. Hope Project \| Nevada Moly LLC \| POS-Minerals Corporation
Cash commitments
Balance of reserve account	$ 36.0