Related Party Transactions (Details)											3 Months Ended		12 Months Ended
Related Party Transactions (Details)	Dec. 11, 2025 USD ($)	May 13, 2024 shares	Mar. 08, 2024 USD ($)	Mar. 07, 2024 USD ($) Directors $ / shares shares	Feb. 15, 2024 USD ($)	Dec. 29, 2023 USD ($) shares	Dec. 17, 2021 shares	Mar. 22, 2021 Directors shares	Feb. 01, 2021 shares	Nov. 29, 2020 USD ($) shares	Mar. 31, 2026 USD ($) $ / shares shares	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Related Party Transactions [Line Items]
Administrative services fees											$ 15,000
Proceeds from related party											115,000
Sponsor [Member]
Related Party Transactions [Line Items]
Advances from related party													$ 43,625
Due from sponsor											5,254		5,254
Related Party [Member]
Related Party Transactions [Line Items]
Advances from related party											1,313		1,313
Repaid amount											0
Promissory notes outstanding											515,000		400,000
Proceeds from related party													1,313
Administrative Services Agreement [Member] \| Sponsor [Member]
Related Party Transactions [Line Items]
Administrative services fees			$ 5,000
Working Capital Loans [Member] \| Sponsor [Member]
Related Party Transactions [Line Items]
Maximum amount of loan convertible into warrants											$ 1,500,000
Price per warrant (in Dollars per share) \| $ / shares											$ 1
Working capital loans
GPIC, LLC [Member] \| Promissory Note With Related Party [Member] \| Related Party [Member]
Related Party Transactions [Line Items]
Maximum borrowing loan										$ 700,000
IDS III LLC [Member] \| Related Party [Member]
Related Party Transactions [Line Items]
Promissory notes outstanding											130,000		100,000
IDS III LLC [Member] \| Promissory Note With Related Party [Member] \| Sponsor [Member]
Related Party Transactions [Line Items]
Unsecured promissory note						$ 400,000
Boxcar Partners Two, LLC [Member] \| Sponsor [Member] \| Minimum [Member]
Related Party Transactions [Line Items]
Unsecured promissory note	$ 125,000
Boxcar Partners Two, LLC [Member] \| Sponsor [Member] \| Maximum [Member]
Related Party Transactions [Line Items]
Unsecured promissory note	$ 130,000
Boxcar Partners Two, LLC [Member] \| Related Party [Member]
Related Party Transactions [Line Items]
Promissory notes outstanding											130,000		100,000
Boxcar Partners Two, LLC [Member] \| Promissory Note With Related Party [Member] \| Sponsor [Member]
Related Party Transactions [Line Items]
Unsecured promissory note					$ 125,000
GPIAC II, LLC [Member] \| Related Party [Member]
Related Party Transactions [Line Items]
Promissory notes outstanding											$ 255,000		$ 200,000
Founder Shares [Member]
Related Party Transactions [Line Items]
Number of shares issued value										$ 25,000
Founder Shares [Member] \| Sponsor [Member]
Related Party Transactions [Line Items]
Number of shares issued (in Shares) \| shares				25,000
Stock price trigger to transfer, assign or sell any shares after the completion of the business combination (in Dollars per share) \| $ / shares				$ 12							$ 12
Transfer, assign or sell threshold trading days				20 days							20 days
Transfer, assign or sell Any shares threshold consecutive trading days				30 days							30 days
Threshold period after business combination				150 days							150 days
Number of shares granted (in Shares) \| shares				75,000
Number Of Directors To Whom Shares Transferred (in Directors) \| Directors				3
Share price (in Dollars per share) \| $ / shares				$ 0.0034
Share transfer consideration from each director				$ 86.96
Share transfer consideration				$ 260.88
Founder Shares [Member] \| GP Sponsor [Member]
Related Party Transactions [Line Items]
Number of shares issued (in Shares) \| shares								3,543,750
Number of independent directors to whom shares transferred (in Directors) \| Directors								4
Founder Shares [Member] \| GP Sponsor [Member] \| Independent Directors [Member]
Related Party Transactions [Line Items]
Number of shares issued (in Shares) \| shares								100,000
Founder Shares [Member] \| Class B Ordinary Shares [Member]
Related Party Transactions [Line Items]
Number of shares issued (in Shares) \| shares							9,583,334
Ordinary shares subject to forfeiture \| shares						2,395,834
Founder Shares [Member] \| Class B Ordinary Shares [Member] \| Sponsor [Member]
Related Party Transactions [Line Items]
Number of shares issued (in Shares) \| shares							2,395,834			11,500,000
Shares outstanding (in Shares) \| shares						7,187,500
Percentage of issued and outstanding shares											20.00%
Founder Shares [Member] \| Class B Ordinary Shares [Member] \| GP Sponsor [Member]
Related Party Transactions [Line Items]
Number of shares issued (in Shares) \| shares								25,000
Shares outstanding (in Shares) \| shares									7,187,500
Over-Allotment Option [Member] \| Underwriters [Member]
Related Party Transactions [Line Items]
Number of shares not subject to forfeiture (in Shares) \| shares		937,500
Over-Allotment Option [Member] \| Class B Ordinary Shares [Member]
Related Party Transactions [Line Items]
Ordinary shares subject to forfeiture \| shares											937,500
Number of shares cancelled due to share surrender \| shares									4,312,500

GP-Act III Acquisition Corp. 10-Q