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

No definition available.

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Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of economic interest in an investment that may be obtained by an entity.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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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

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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

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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
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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

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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

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

- Definition

The percent of membership interest that the company is contingently obligated to sell upon certain conditions or right exercises.

+ References

No definition available.

+ Details

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

- Definition

Represents the percentage of economic interest in an investment that may be obtained by an entity.

+ References

No definition available.

+ Details

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

- 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

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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

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Data Type:	xbrli:sharesItemType
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Note 1 - Organization and Business (Details Textual) $ in Thousands, shares in Millions			1 Months Ended	6 Months Ended	12 Months Ended
	Nov. 10, 2017 a	Nov. 29, 2010 USD ($) a shares	Sep. 30, 2012 a	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jan. 18, 2019	Jan. 08, 2015 USD ($)	Sep. 29, 2012
Number of Wholly Owned Subsidiaries				2
Long-term Debt, Total				$ 0
The Joint Venture Company [Member]
Exploration Budget					$ 10,700
Exploration Budget, Amount Spent					$ 10,100
Equity Method Investment, Ownership Percentage				60.00%
Royal Gold [Member] \| The Joint Venture Company [Member]
Initial Investment to Fund Exploration Activity							$ 5,000
Percentage of Economic Interest That May Be Obtained							40.00%
Amount of Economic Interest That May Be Obtained							$ 30,000
Payments to Acquire Interest in Joint Venture				$ 33,000
Percentage Ownership in Company				40.00%
CORE Alaska [Member] \| Subsequent Event [Member]
Percent Membership Interest, Contingent Sale, Percent						20.00%
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		$ 3,500
Sale of Stock, Number of Shares Issued in Transaction \| shares		1.6
Royal Gold [Member]
Overriding Royalty Interest		3.00%
JEX [Member]
Overriding Royalty Interest				3.00%				2.00%
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%