SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025
Supplemental cash flow information:
Cash paid for interest, net of amounts capitalized	$ 26,535	$ 22,790
Change in construction payables and accrued construction costs	51,585	8,012
Supplemental non-cash investing and financing activities:
Property, plant and equipment acquired with equipment notes	9,523	27,029
Operating right-of-use assets obtained in exchange for lease liabilities	7,977	6,917
TSIF government award receivable used for construction	10,075	0
Series A Convertible Preferred Stock
Supplemental non-cash investing and financing activities:
Issuance of Issued Instrument in exchange for PPA Upfront Asset	0	118,998
DOD Warrant
Supplemental non-cash investing and financing activities:
Issuance of Issued Instrument in exchange for PPA Upfront Asset	0	75,142
Samarium Project Loan
Supplemental non-cash investing and financing activities:
Issuance of Issued Instrument in exchange for PPA Upfront Asset	$ 0	$ 24,460

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Other Receivable from Government Reimbursements for Property, Plant and Equipment, Non Cash Investing Activity

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The increase (decrease) during the reporting period of obligations, not classified as trade payables, incurred and payable for the acquisition of merchandise, materials, supplies, and services pertaining to construction projects.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
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Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
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Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
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-URI https://asc.fasb.org/1943274/2147482913/230-10-50-3

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