XML 11 R1.htm IDEA: XBRL DOCUMENT v3.19.2
Document and Entity Information - shares
 9 Months Ended
Jun. 30, 2019
Aug. 01, 2019
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q3  
Trading Symbol GENC  
Entity Registrant Name GENCOR INDUSTRIES INC  
Entity Central Index Key 0000064472  
Current Fiscal Year End Date --09-30  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Security Exchange Name NASDAQ  
Title of 12(b) Security Common Stock  
Entity Address, State or Province FL  
Common Stock [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   12,252,337
Class B Stock [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   2,288,857