v3.26.1
Cover
3 Months Ended
Mar. 31, 2026
Cover [Abstract]  
Document Type S-4/A
Amendment Flag true
Amendment Description Amendment 1
Document Fiscal Period Focus Q1
Document Fiscal Year Focus 2026
Entity Registrant Name MCCARTHY FINNEY, INC.
Entity Central Index Key 0002131882
Entity Tax Identification Number 41-3005249
Entity Incorporation, State or Country Code DE
Entity Address, Address Line One 1680 38th Street
Entity Address, Address Line Two Suite 130
Entity Address, City or Town Boulder
Entity Address, State or Province CO
Entity Address, Postal Zip Code 80301
City Area Code (303)
Local Phone Number 219-9771
Entity Filer Category Non-accelerated Filer
Entity Small Business true
Entity Emerging Growth Company true
Elected Not To Use the Extended Transition Period false