SUPPLEMENTAL PRO FORMA INFORMATION - Equity method investment (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
EQUITY METHOD INVESTMENT
Carrying value of investment				$ 9,380,343
Total external revenue			$ 2,010,798,385	1,672,378,581
Gross profit			127,719,566	100,548,776
Net income before income taxes	$ 8,000,000.0	$ 15,200,000	21,475,504	16,688,287
Net income attributable to AMCON, net of tax	$ 6,000,000.0	$ 12,100,000	16,672,257	15,545,265
Team Sledd
EQUITY METHOD INVESTMENT
Total external revenue			393,606,372	684,539,392
Gross profit			21,759,753	34,962,326
Net income before income taxes			4,498,190	8,597,997
Net income attributable to AMCON, net of tax			$ 1,670,133	$ 3,357,978
Team Sledd
EQUITY METHOD INVESTMENT
Minority interest (as a percent)				49.00%
Carrying value of investment				$ 9,400,000