v3.26.1
Cover - USD ($)
12 Months Ended
Nov. 30, 2025
Feb. 10, 2026
May 31, 2025
Document Type 10-K/A    
Amendment Flag true    
Amendment Description This Amendment No. 1 (this “Amendment”) on Form 10-K/A amends the Annual Report on Form 10-K for the year ended November 30, 2025 of Legato Merger Corp. III (the “Company”), filed with the Securities and Exchange Commission on February 10, 2026 (the “Original Form 10-K”) to include certain additional disclosure in Item 9A of such Original Form 10-K.   Other than as set forth above, this Amendment does not reflect events occurring after the filing of the Original Form 10-K, and no other information in the Original Form 10-K is amended hereby. Other events or circumstances occurring after the date of the Original Form 10-K or other disclosures necessary to reflect subsequent events have not been updated subsequent to the date of the Original Form 10-K. Accordingly, this Amendment should be read in conjunction with the Original Form 10-K and our filings with the SEC subsequent thereto.    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Nov. 30, 2025    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2025    
Current Fiscal Year End Date --11-30    
Entity File Number 001-41945    
Entity Registrant Name Legato Merger Corp. III    
Entity Central Index Key 0002002038    
Entity Tax Identification Number 98-1761148    
Entity Incorporation, State or Country Code E9    
Entity Address, Address Line One 777 Third Avenue    
Entity Address, Address Line Two 37th Floor    
Entity Address, City or Town New York    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 10017    
City Area Code (212)    
Local Phone Number 319-7676    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Elected Not To Use the Extended Transition Period false    
Entity Shell Company true    
Entity Public Float     $ 213,727,500
Entity Common Stock, Shares Outstanding   25,799,375  
Document Financial Statement Error Correction [Flag] false    
Units, each consisting of one ordinary share, $0.0001 par value, and one-half of one redeemable warrant      
Title of 12(b) Security Units, each consisting of one ordinary share, $0.0001 par value, and one-half of one redeemable warrant    
Trading Symbol LEGT U    
Security Exchange Name NYSEAMER    
Ordinary Shares, par value $0.0001 per share      
Title of 12(b) Security Ordinary Shares, par value $0.0001 per share    
Trading Symbol LEGT    
Security Exchange Name NYSEAMER    
Redeemable warrants, exercisable for ordinary shares at an exercise price of $11.50 per share      
Title of 12(b) Security Redeemable warrants, exercisable for ordinary shares at an exercise price of $11.50 per share    
Trading Symbol LEGT WS    
Security Exchange Name NYSEAMER