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Organization and Business (Details) (USD $)
In Millions, unless otherwise specified
 0 Months Ended 46 Months Ended 9 Months Ended
Nov. 29, 2010
Oct. 31, 2018
Mar. 31, 2015
Jan. 08, 2015
Sep. 29, 2014
Subsidiary shares issued 1.6us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction        
Acreage of Unpatented Mining Claims-Alaska     71,896ctgo_AcreageofUnpatentedMiningClaimsAlaska    
Royal Gold initial investment       $ 5ctgo_RoyalGoldinitialinvestment  
Royal Gold percentage of interest in Joint Venture     0.00%ctgo_RoyalGoldpercentageofinterestinJointVenture    
Contango's percentage of interest in Joint Venture Company     100.00%ctgo_ContangospercentageofinterestinJointVentureCompany    
royalgoldjointventure   30ctgo_Royalgoldjointventure      
joint adventure economic interest       40.00%ctgo_Jointadventureeconomicinterest  
additional new mining claims-state of Alaska     59ctgo_AdditionalnewminingclaimsstateofAlaska    
unpatented mining claims-Eagle     9,439ctgo_UnpatentedminingclaimsEagle    
Native Village of Tetlin Land [Member]          
Percentage of Leasehold Interest 100.00%ctgo_PercentageOfLeaseholdInterest
/ us-gaap_StatementGeographicalAxis
= ctgo_NativeVillageOfTetlinLandMember		        
Leasehold Interest Acreage 675,000ctgo_LeaseholdInterestAcreage
/ us-gaap_StatementGeographicalAxis
= ctgo_NativeVillageOfTetlinLandMember		        
Initial and Renewal Terms of Leases and Concessions on Undeveloped Acreage     10 years    
Contango [Member]          
Parent contribution 3.5ctgo_ParentContribution
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= ctgo_ContangoMember		        
JEX [Member]          
Overriding royalty interest     3.00%ctgo_OverridingRoyaltyInterest
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= ctgo_JexMember		    
JEX [Member] | ALASKA          
the number of unpatented state of Alaska mining claims     474ctgo_ThenumberofunpatentedstateofAlaskaminingclaims
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= ctgo_JexMember
/ us-gaap_StatementGeographicalAxis
= stpr_AK		    
Overriding royalty interest     2.00%ctgo_OverridingRoyaltyInterest
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= ctgo_JexMember
/ us-gaap_StatementGeographicalAxis
= stpr_AK		   2.00%ctgo_OverridingRoyaltyInterest
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= ctgo_JexMember
/ us-gaap_StatementGeographicalAxis
= stpr_AK
Unpatented Mining Claims from the State of Alaska for Gold and Minerals [Member]          
Acreage of Unpatented Mining Claims 18,021ctgo_AcreageOfUnpatentedMiningClaims
/ ctgo_UnpatentedMiningClaimsAxis
= ctgo_UnpatentedMiningClaimsFromStateOfAlaskaForGoldAndMineralsMember