v3.26.1
Cover
Mar. 26, 2026
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Mar. 26, 2026
Entity File Number 000-56829
Entity Registrant Name URSB Bancorp, Inc.
Entity Central Index Key 0002084261
Entity Tax Identification Number 39-4348578
Entity Incorporation, State or Country Code MD
Entity Address, Address Line One 11-15 Cooke Avenue
Entity Address, City or Town Carteret
Entity Address, State or Province NJ
Entity Address, Postal Zip Code 07008
City Area Code 732
Local Phone Number 541-5445
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company true
Elected Not To Use the Extended Transition Period false