v3.25.2
S-K 1604(c) De-SPAC Dilution
$ / shares in Units, $ in Thousands
 6 Months Ended
Jun. 30, 2025
USD ($)
$ / shares
shares
No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Per Share (in Dollars per share) | $ / shares $ 10
De-SPAC, Net Tangible Book Value, Adjusted $ 273,765
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 33,750,000
De-SPAC, Net Tangible Book Value, Adjusted, Per Share (in Dollars per share) | $ / shares $ 8.11
De-SPAC, Net Tangible Book Value, Amount of Dilution Per Share (in Dollars per share) | $ / shares $ 1.89
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,248,732
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 134,939,712
Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Per Share (in Dollars per share) | $ / shares $ 10
De-SPAC, Net Tangible Book Value, Adjusted $ 238,732
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 30,394,497
De-SPAC, Net Tangible Book Value, Adjusted, Per Share (in Dollars per share) | $ / shares $ 7.85
De-SPAC, Net Tangible Book Value, Amount of Dilution Per Share (in Dollars per share) | $ / shares $ 2.15
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,215,177
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 131,584,209
Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Per Share (in Dollars per share) | $ / shares $ 10
De-SPAC, Net Tangible Book Value, Adjusted $ 203,698
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 27,038,993
De-SPAC, Net Tangible Book Value, Adjusted, Per Share (in Dollars per share) | $ / shares $ 7.53
De-SPAC, Net Tangible Book Value, Amount of Dilution Per Share (in Dollars per share) | $ / shares $ 2.47
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,282,287
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 128,228,705
Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Per Share (in Dollars per share) | $ / shares $ 10
De-SPAC, Net Tangible Book Value, Adjusted $ 168,665
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 23,683,490
De-SPAC, Net Tangible Book Value, Adjusted, Per Share (in Dollars per share) | $ / shares $ 7.12
De-SPAC, Net Tangible Book Value, Amount of Dilution Per Share (in Dollars per share) | $ / shares $ 2.88
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,349,397
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 124,873,202
Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Per Share (in Dollars per share) | $ / shares $ 10
De-SPAC, Net Tangible Book Value, Adjusted $ 133,631
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 20,327,986
De-SPAC, Net Tangible Book Value, Adjusted, Per Share (in Dollars per share) | $ / shares $ 6.57
De-SPAC, Net Tangible Book Value, Amount of Dilution Per Share (in Dollars per share) | $ / shares $ 3.43
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,315,842
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 121,517,698
Public Units [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 23,000,000
Public Units [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 19,644,497
Public Units [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 16,288,993
Public Units [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 12,933,490
Public Units [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 9,577,986
Founder Shares [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,750,000
Founder Shares [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,750,000
Founder Shares [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,750,000
Founder Shares [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,750,000
Founder Shares [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,750,000
PIPE Shares [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,000,000
PIPE Shares [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,000,000
PIPE Shares [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,000,000
PIPE Shares [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,000,000
PIPE Shares [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Number of Shares Used to Determine Net Tangible Book Value, Adjusted (in Shares) | shares 5,000,000
HCM II Shares [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 337,500
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 33,750,000
HCM II Shares [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 303,945
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 30,394,497
HCM II Shares [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 270,390
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 27,038,993
HCM II Shares [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 236,835
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 23,683,490
HCM II Shares [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 203,280
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 20,327,986
Terrestrial Energy Shares [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,011,987
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 101,189,712
Terrestrial Energy Shares [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,011,987
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 101,189,712
Terrestrial Energy Shares [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,011,987
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 101,189,712
Terrestrial Energy Shares [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,011,987
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 101,189,712
Terrestrial Energy Shares [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Company Valuation at which Shares not Redeemed are at least IPO Value per Share $ 1,011,987
De-SPAC, Number of Shares Used, Adjustment (in Shares) | shares 101,189,712
HCM II’s Net Tangible Book Value [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted $ (13,956)
HCM II’s Net Tangible Book Value [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (13,956)
HCM II’s Net Tangible Book Value [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (13,956)
HCM II’s Net Tangible Book Value [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (13,956)
HCM II’s Net Tangible Book Value [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (13,956)
Transaction Costs Attributed to HCM II [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (3,470)
Transaction Costs Attributed to HCM II [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (3,470)
Transaction Costs Attributed to HCM II [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (3,470)
Transaction Costs Attributed to HCM II [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (3,470)
Transaction Costs Attributed to HCM II [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted (3,470)
PIPE Financing [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 51,057
PIPE Financing [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 51,057
PIPE Financing [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 51,057
PIPE Financing [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 51,057
PIPE Financing [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 51,057
Funds Released from Trust [Member] | No Redemption [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 240,134
Funds Released from Trust [Member] | Redemption at 25 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 205,101
Funds Released from Trust [Member] | Redemption at 50 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 170,067
Funds Released from Trust [Member] | Redemption at 75 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted 135,034
Funds Released from Trust [Member] | Redemption at 100 Percent of Maximum [Member]  
De-SPAC, Net Tangible Book Value [Line Items]  
De-SPAC, Net Tangible Book Value, Adjusted $ 100,000