Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2021	Nov. 04, 2021	Mar. 31, 2021
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	1-15589
Entity Registrant Name	AMCON DISTRIBUTING CO
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-0702918
Entity Address, Address Line One	7405 Irvington Road
Entity Address, City or Town	Omaha
Entity Address, State or Province	NE
Entity Address, Postal Zip Code	68122
City Area Code	402
Local Phone Number	331-3727
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	DIT
Security Exchange Name	NYSEAMER
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			$ 17,542,562
Entity Common Stock, Shares Outstanding		582,789
Entity Central Index Key	0000928465
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false