v3.26.1
Document and Entity Information
Apr. 01, 2026
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Apr. 01, 2026
Entity File Number 333-291808
Entity Registrant Name Ballston Spa Bancorp, Inc.
Entity Central Index Key 0002094107
Entity Incorporation, State or Country Code NY
Entity Tax Identification Number 74-2245601
Entity Address, Address Line One 990 State Route 67
Entity Address, City or Town Ballston Spa
Entity Address, State or Province NY
Entity Address, Postal Zip Code 12020
City Area Code 518
Local Phone Number 363-8199
Entity Emerging Growth Company true
Entity Ex Transition Period false
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(g) Security Common Stock, par value $12.50 per share
Trading Symbol BSPA