XML 13 R1.htm IDEA: XBRL DOCUMENT v3.20.4
Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2020
Dec. 15, 2020
Mar. 31, 2020
Entity Registrant Name Magyar Bancorp, Inc.    
Entity Central Index Key 0001337068    
Document Type 10-K    
Document Period End Date Sep. 30, 2020    
Amendment Flag false    
Current Fiscal Year End Date --09-30    
Is Entity a Well-known Seasoned Issuer? No    
Is Entity a Voluntary Filer? No    
Is Entity's Reporting Status Current? Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Shell Company false    
Entity Emerging Growth Company false    
Entity Public Float     $ 23.5
Entity Common Stock, Shares Outstanding   5,810,746  
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2020    
Entity Interactive Data Current Yes    
Entity Incorporation, State or Country Code DE    
Entity File Number 000-51726    
Document Annual Report true    
Document Transition Report false    
Magyar Bancorp, MHC [Member]      
Entity Common Stock, Shares Owned by Registrant's mutual holding company   3,200,450