Represents information pertaining to the acreage of unpatented mining claims contributed by the parent.

No definition available.

Name:	ctgo_AcreageOfUnpatentedMiningClaims
Namespace Prefix:	ctgo_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The budget approved for exploration purposes for the 2018 calendar year.

+ References

No definition available.

+ Details

Name:	ctgo_ExplorationBudget
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the amount of the exploration budget that has been spent.

+ References

No definition available.

+ Details

Name:	ctgo_ExplorationBudgetAmountSpent
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the amount of initial investment for the purpose of funding exploration activity.

+ References

No definition available.

+ Details

Name:	ctgo_InitialInvestmentToFundExplorationActivity
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the acreage of the leasehold interest contributed by the parent entity.

+ References

No definition available.

+ Details

Name:	ctgo_LeaseholdInterestAcreage
Namespace Prefix:	ctgo_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the area of mining claims acquired during the period.

+ References

No definition available.

+ Details

Name:	ctgo_MiningClaimsAcquiredArea
Namespace Prefix:	ctgo_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of mining claims acquired during the period.

+ References

No definition available.

+ Details

Name:	ctgo_NumberOfMiningClaimsAcquired
Namespace Prefix:	ctgo_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of wholly owned subsidiaries of the entity as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	ctgo_NumberOfWhollyOwnedSubsidiaries
Namespace Prefix:	ctgo_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the overriding royalty interest the company would be required to pay if any of the properties are placed into commercial production.

+ References

No definition available.

+ Details

Name:	ctgo_OverridingRoyaltyInterest
Namespace Prefix:	ctgo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of cash contribution by the parent during the period.

+ References

No definition available.

+ Details

Name:	ctgo_ParentContribution
Namespace Prefix:	ctgo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the percentage of the leasehold interest contributed by the parent.

+ References

No definition available.

+ Details

Name:	ctgo_PercentageOfLeaseholdInterest
Namespace Prefix:	ctgo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents an entity's ownership percentage in a company as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	ctgo_PercentageOwnershipInCompany
Namespace Prefix:	ctgo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the production royalty percentage pertaining to a property.

+ References

No definition available.

+ Details

Name:	ctgo_ProductionRoyaltyPercentage
Namespace Prefix:	ctgo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the royalty interest sold during the period.

+ References

No definition available.

+ Details

Name:	ctgo_RoyaltyInterestSold
Namespace Prefix:	ctgo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireInterestInJointVenture
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=ctgo_TheJointVentureCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ctgo_UnpatentedMiningClaimsFromTheStateOfAlaskaForGoldAndMineralsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ctgo_UnpatentedStateOfAlaskaMiningClaimsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=ctgo_NativeVillageOfTetlinLandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=ctgo_TheTetlinLeaseAndUnpatentedStateOfAlaskaMiningClaimsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

Note 1 - Organization and Business (Details Textual) shares in Millions, $ in Millions				1 Months Ended	6 Months Ended	12 Months Ended
	Nov. 10, 2017 a	Sep. 29, 2014	Nov. 29, 2010 USD ($) a shares	Sep. 30, 2012 a	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jan. 08, 2015 USD ($)
Number of Wholly Owned Subsidiaries					2	2
Sale of Stock, Number of Shares Issued in Transaction \| shares			1.6
The Joint Venture Company [Member]
Exploration Budget					$ 9.1
Exploration Budget, Amount Spent					$ 4.6
Royal Gold [Member] \| The Joint Venture Company [Member]
Initial Investment to Fund Exploration Activity							$ 5.0
Payments to Acquire Interest in Joint Venture						$ 31.7
Percentage Ownership in Company					40.00%	40.00%
Unpatented Mining Claims from the State of Alaska for Gold and Minerals [Member]
Acreage of Unpatented Mining Claims \| a			18,021
Unpatented State of Alaska Mining Claims [Member] \| The Joint Venture Company [Member]
Number of Mining Claims Acquired	541
Mining Claims Acquired, Area \| a	84,840
Production Royalty Percentage	3.00%
Native Village of Tetlin Land [Member]
Percentage of Leasehold Interest			100.00%
Leasehold Interest Acreage \| a			675,000
Contango [Member]
Parent Contribution			$ 3.5
Royal Gold [Member]
Overriding Royalty Interest			3.00%
Royal Gold [Member] \| The Tetlin Lease and Unpatented State of Alaska Mining Claims [Member] \| JEX [Member]
Royalty Interest Sold		3.00%
Royal Gold [Member] \| Unpatented State of Alaska Mining Claims [Member] \| JEX [Member]
Royalty Interest Sold		2.00%
JEX [Member]
Overriding Royalty Interest				2.00%	3.00%	3.00%
JEX [Member] \| Unpatented State of Alaska Mining Claims [Member]
Number of Mining Claims Acquired				474
Mining Claims Acquired, Area \| a				71,896
Production Royalty Percentage				2.00%