Document and Entity Information	3 Months Ended
	Dec. 31, 2012	Feb. 01, 2013 Common stock	Feb. 01, 2013 Class B stock
Entity Registrant Name	GENCOR INDUSTRIES INC
Entity Central Index Key	0000064472
Document Type	10-Q
Document Period End Date	Dec. 31, 2012
Amendment Flag	false
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--09-30
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		8,008,632	1,509,238