Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2020	Nov. 06, 2020	Mar. 31, 2020
Document and Entity Information
Document Type	10-K
Document Period End Date	Sep. 30, 2020
Entity Registrant Name	AMCON DISTRIBUTING CO
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 11,353,860
Entity Common Stock, Shares Outstanding		551,437
Entity Central Index Key	0000928465
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false