Joint Venture With General Motors - Additional Information (Details) - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended | |
|---|---|---|---|
Aug. 05, 2025 |
Jun. 30, 2026 |
Dec. 31, 2025 |
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| Joint Venture with GM [Member] | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Formation description | On October 15, 2024, the Company and GM entered into an investment agreement (“Investment Agreement”) to establish a joint venture for the purpose of funding, developing, constructing and operating Thacker Pass as described in Note 4 to the Fiscal 2025 Annual Financial Statements. As of the closing of the JV in December 2024, and as at June 30, 2026, | ||
| Joint Venture Closing Date1 | 2024-12 | ||
| Ownership percentage | 62.00% | ||
| Cash and Restricted Cash | $ 530.3 | $ 412.6 | |
| Management services agreement and incentive compensation | $ 15.1 | $ 9.2 | |
| General Motors Holdings LLC [Member] | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Ownership percentage | 38.00% | ||
| Citibank N A Member | |||
| Schedule of Equity Method Investments [Line Items] | |||
| Letters of credit released amount | $ 195.0 |
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- Definition Joint venture closing date1. No definition available.
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Description of joint venture formation. Includes, but is not limited to, purpose for formation, asset and liability recognized at formation date, and factor making up recognized goodwill. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of expense for management and incentive fees for performance under arrangement to manage operation, including, but not limited to, managing investment. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of cash and cash equivalent restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposit with financial institution, and account with general characteristic of demand deposit. Cash equivalent includes, but is not limited to, short-term, highly liquid investment that is both readily convertible to known amount of cash and so near maturity that it presents insignificant risk of change in value because of change in interest rate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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