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Exploration Contracts (Details) - Allseas Group S.A - USD ($) shares in Millions, $ in Millions |  |  | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Nov. 09, 2022 | Apr. 25, 2022 | Dec. 31, 2022 | Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021 | Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Amount of expenses |  |  |  | $ 1.3 | $ 12.9 | $ 4.0 | $ 12.9 |
Owned common shares (in shares) |  |  |  | 22.7 |  | 22.7 |  | 16.2
Common shares outstanding, percentage |  |  |  |  |  | 8.60% |  | 7.20%
PMTS |  |  |  |  |  |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Payment | $ 10.0 |  |  |  |  |  |  |
PMTA |  |  |  |  |  |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Payment |  | $ 10.0 |  |  |  |  |  |
Completion of the PMTS |  |  |  |  |  |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |  |
Amount payable |  |  | $ 10.0 |  |  |  |  |

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