v3.25.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2025
Apr. 30, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2025  
Document Transition Report false  
Securities Act File Number 001-41384  
Entity Registrant Name Hanover Bancorp, Inc. /NY  
Entity Incorporation, State or Country Code NY  
Entity Tax Identification Number 81-3324480  
Entity Address, Address Line One 80 East Jericho Turnpike  
Entity Address, City or Town Mineola  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 11501  
City Area Code 516  
Local Phone Number 548-8500  
Title of 12(b) Security Common stock  
Trading Symbol HNVR  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   7,228,731
Entity Central Index Key 0001828588  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q1  
Amendment Flag false