DEBT - Credit Facility (Details) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Revolving credit facility
Revolving portion of the facility	$ 61,971,682	$ 60,376,714
Facility
Revolving credit facility
Revolving portion of the facility	$ 61,971,682	60,376,714
Interest rate (as a percent)	2.41%
Revolving credit limit	$ 109,600,000
Increase in borrowing capacity available under loan accordion	25,000,000
Additional credit advances for certain inventory purchases	$ 10,000,000
Automatic renewal period of agreement unless terminated	1 year
Unused commitment fee (as a percent)	0.25%
Period considered for computing fixed charge coverage ratio	12 months
Threshold of excess availability of credit as a percentage of maximum loan limit, required for financial covenant compliance	10.00%
Restricted amount of dividends on common stock, or other distributions or investments	$ 3,500,000
Borrowings on the facility	1,500,000,000	1,400,000,000
Payments on the facility	1,500,000,000	1,400,000,000
Net advances (payments) on the Facility	1,600,000	$ 24,900,000
Credit available under the Facility	$ 47,600,000
Facility | LIBOR
Revolving credit facility
Variable rate basis	LIBOR
Floor variable rate (as a percent)	1.00%
Facility | Prime rate
Revolving credit facility
Variable rate basis	Prime rate
Facility | Minimum
Revolving credit facility
Notice period prior to the end of any original or renewal term of the agreement required for terminating the agreement either by the borrower or lender	90 days
Fixed charge coverage ratio	1.0
Facility | Minimum | LIBOR
Revolving credit facility
Basis points added to reference rate (as a percent)	1.25%
Facility | Maximum
Revolving credit facility
Revolving credit limit	$ 110,000,000
Facility | Maximum | LIBOR
Revolving credit facility
Basis points added to reference rate (as a percent)	1.50%