Percentage of revenue payable annually to total revenue as repayment under the Contribution Agreement.

No definition available.

Name:	imsr_GovernmentAssistanceAnnualRepaymentRateToRevenue
Namespace Prefix:	imsr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum repayment amount expressed as a multiple of the actual contribution received under the Contribution Agreement.

+ References

No definition available.

+ Details

Name:	imsr_GovernmentAssistanceRepaymentMultiplier
Namespace Prefix:	imsr_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of government assistance awarded that comprises amount received, receivable, and to be received unless condition for government assistance is not met. Includes, but is not limited to, government grant, assistance, incentive, award, subsidy, and loan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 832
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483507/832-10-50-3

+ Details

Name:	us-gaap_GovernmentAssistanceAwardAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of liability from government assistance, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 832
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483507/832-10-50-3

+ Details

Name:	us-gaap_GovernmentAssistanceLiabilityCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indicates line item in statement of financial position that includes liability from government assistance, classified as current.

+ References

+ Details

Name:	us-gaap_GovernmentAssistanceLiabilityCurrentStatementOfFinancialPositionExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	instant

- 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.

+ References

+ Details

Name:	us-gaap_GovernmentAssistanceLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Duration of government assistance transaction, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 832
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483507/832-10-50-4

+ Details

Name:	us-gaap_GovernmentAssistanceTransactionDuration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Government Grants (Details)	Sep. 02, 2020 CAD ($)	Dec. 31, 2025 USD ($)	Mar. 31, 2025	Dec. 31, 2024 USD ($)
Government Grants
Total contribution		$ 14,925,373
Repayment duration of government grant	25 years
Repayment multiplier for government assistance	1.75
Annual repayment rate for government assistance based on revenue			3.00%
Repayment accrual		$ 0		$ 10,274
Government Assistance, Liability, Current, Statement of Financial Position [Extensible Enumeration]		Accounts Payable and Accrued Liabilities, Current		Accounts Payable and Accrued Liabilities, Current
Maximum
Government Grants
Total contribution	$ 20,000,000