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Organization and Business (Details) shares in Millions |  | 3 Months Ended | 21 Months Ended | 46 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 29, 2010 USD ($) a shares | Sep. 30, 2016 USD ($) Rate | Sep. 30, 2016 USD ($) Rate | Oct. 31, 2018 USD ($) | Sep. 30, 2015 | Jan. 08, 2015 USD ($) | Sep. 29, 2014 | Sep. 01, 2012 a
Subsidiary shares issued | shares | 1.6 |  |  |  |  |  |  |
Acreage of Unpatented Mining Claims-Alaska | a |  |  |  |  |  |  |  | 71,896
Royal Gold initial investment |  |  |  |  |  | $ 5,000,000 |  |
Contango's percentage of interest in Joint Venture Company |  | 85.00% | 85.00% |  | 100.00% |  |  |
royalgoldjointventure |  |  |  | $ 30,000,000 |  |  |  |
joint adventure economic interest |  |  |  |  |  | 40.00% |  |
Investment by Joint Venture Partner |  | $ 2,700,000 | $ 13,400,000 |  |  |  |  |
Royal Alaska Joint Venture Percentage | Rate |  | 15.10% | 15.10% |  |  |  |  |
Native Village of Tetlin Land [Member] |  |  |  |  |  |  |  |
Percentage of Leasehold Interest | 100.00% |  |  |  |  |  |  |
Leasehold Interest Acreage | a | 675,000 |  |  |  |  |  |  |
Initial and Renewal Terms of Leases and Concessions on Undeveloped Acreage |  | 10 years |  |  |  |  |  |
Contango [Member] |  |  |  |  |  |  |  |
Parent contribution | $ 3,500,000 |  |  |  |  |  |  |
JEX [Member] |  |  |  |  |  |  |  |
Overriding royalty interest |  | 3.00% | 3.00% |  |  |  |  |
JEX [Member] | ALASKA |  |  |  |  |  |  |  |
the number of unpatented state of Alaska mining claims |  |  |  |  |  |  |  | 474
Overriding royalty interest |  |  |  |  |  |  | 2.00% | 2.00%
Unpatented Mining Claims from the State of Alaska for Gold and Minerals [Member] |  |  |  |  |  |  |  |
Acreage of Unpatented Mining Claims | a | 18,021 |  |  |  |  |  |  |

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