v3.26.1
Cover - USD ($)
 12 Months Ended
Mar. 31, 2026
Jun. 12, 2026
Sep. 30, 2025
Document Information Line Items      
Entity Registrant Name Piermont Valley Acquisition Corp    
Entity Central Index Key 0001865248    
Document Type 10-K    
Amendment Flag false    
Entity Voluntary Filers No    
Current Fiscal Year End Date --03-31    
Entity Well Known Seasoned Issuer No    
Entity Small Business true    
Entity Shell Company true    
Entity Emerging Growth Company true    
Entity Current Reporting Status Yes    
Document Period End Date Mar. 31, 2026    
Entity Filer Category Non-accelerated Filer    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2026    
Entity Ex Transition Period false    
Entity Common Stock Shares Outstanding   5,954,449  
Entity Public Float     $ 0
Document Annual Report true    
Document Transition Report false    
Document Fin Stmt Error Correction Flag false    
Entity File Number 001-41108    
Entity Incorporation State Country Code E9    
Entity Tax Identification Number 98-1598114    
Entity Address Address Line 1 732 6th Street    
Entity Address Address Line 2 #5386    
Entity Address City Or Town Las Vegas    
Entity Address State Or Province NV    
Entity Address Postal Zip Code 89101    
City Area Code 929    
Icfr Auditor Attestation Flag false    
Auditor Name Aloba, Awomolo & Partners    
Auditor Location Ibadan, Nigeria    
Auditor Firm Id 7275    
Local Phone Number 792-5788    
Entity Interactive Data Current Yes    
Units Each Consisting Of One Share Of Class Common Stock And One Half Of One Warrant [Member]      
Document Information Line Items      
Security 12b Title Units, each consisting of one Class A ordinary share, par value $0.0001, and one-half of one redeemable warrant    
Trading Symbol CMCAU    
Class A ordinary shares, par value      
Document Information Line Items      
Security 12b Title Class A ordinary shares, par value $0.0001 per share    
Trading Symbol CMCAF    
One Warrant Exercisable For One Class A Ordinary Share Member      
Document Information Line Items      
Security 12b Title Warrants, each whole warrant exercisable for one Class A ordinary share, each at an exercise price of $11.50 per share    
Trading Symbol CMCAW