Long-term Debt and Line of Credit - Summary of Long-term Debt and Line of Credit (Details) - USD ($)	6 Months Ended
	Mar. 31, 2026	Sep. 30, 2025
Debt Instrument [Line Items]
Total debt outstanding	$ 357,891,000	$ 415,903,000
Less current portion (net of current debt issuance costs)	(23,606,000)	(77,895,000)
Less unamortized portion of debt issuance costs	(4,307,000)	(3,811,000)
Long-term debt, net of current portion and unamortized debt issuance costs	329,978,000	334,197,000
Term note payable to Truist Bank, secured and bearing interest at 7.20% at March 31, 2026 and 7.25% at September 30, 2025. The note requires quarterly principal payments commencing on December 31, 2022 and maturing with a full repayment on July 31, 2027
Debt Instrument [Line Items]
Total debt outstanding	$ 299,429,000	$ 367,125,000
Debt instrument, interest rate, stated percentage	7.20%	7.25%
Revolving note payable for an amount up to $65.0 million to Truist Bank, secured and bearing interest at 7.17% at March 31, 2026 and 7.56% at September 30, 2025. The note requires full repayment on July 31, 2027
Debt Instrument [Line Items]
Total debt outstanding	$ 57,029,000	$ 47,229,000
Debt instrument, interest rate, stated percentage	7.17%	7.56%
Line of credit facility, maximum borrowing capacity	$ 65,000,000.0
Notes payable to commercial vehicle lenders secured by the value of the vehicles bearing interest at rates ranging from 0.0% to 10.8% per annum. The notes require monthly installment payments of principal and interest ranging from $200 to $1,700 through May 2032
Debt Instrument [Line Items]
Total debt outstanding	$ 1,433,000	$ 1,549,000
Notes payable to commercial vehicle lenders secured by the value of the vehicles bearing interest at rates ranging from 0.0% to 10.8% per annum. The notes require monthly installment payments of principal and interest ranging from $200 to $1,700 through May 2032 | Minimum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	0.00%
Debt instrument, periodic payment	$ 200,000
Notes payable to commercial vehicle lenders secured by the value of the vehicles bearing interest at rates ranging from 0.0% to 10.8% per annum. The notes require monthly installment payments of principal and interest ranging from $200 to $1,700 through May 2032 | Maximum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	10.80%
Debt instrument, periodic payment	$ 1,700,000