Long-term Debt and Line of Credit - Summary of Long-term Debt and Line of Credit (Details) - USD ($)	9 Months Ended
	Jun. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Total debt outstanding	$ 432,782,000	$ 465,140,000
Less current portion (net of debt issuance costs)	(8,632,000)	(29,324,000)
Less unamortized portion of debt issuance costs	(6,551,000)	(7,377,000)
Long-term debt, net of current portion and unamortized debt issuance costs	417,599,000	428,439,000
Term note payable to Truist Bank, secured and bearing interest at 7.80% at June 30, 2024 and 7.53% at September 30, 2023. The note requires quarterly principal payments commencing on December 31, 2022 and maturing with a full repayment on August 9, 2027
Debt Instrument [Line Items]
Total debt outstanding	$ 383,813,000	$ 428,313,000
Debt instrument, interest rate, stated percentage	7.80%	7.53%
Revolving note payable for an amount up to $65.0 million to Truist Bank, secured and bearing interest at 7.81% at June 30, 2024 and 7.50% at September 30, 2023. The note requires full repayment on August 9, 2027
Debt Instrument [Line Items]
Total debt outstanding	$ 45,000,000	$ 30,000,000
Debt instrument, interest rate, stated percentage	7.81%	7.50%
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 $3,100 through April 2029
Debt Instrument [Line Items]
Total debt outstanding	$ 2,843,000	$ 3,645,000
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 $3,100 through April 2029 | 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 $3,100 through April 2029 | Maximum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	10.80%
Debt instrument, periodic payment	$ 3,100,000
Note payable to Norfolk Marine Company, unsecured and bearing interest at 4.0% per annum. The note requires quarterly interest payments, with a balloon payment of principal due on December 1, 2024
Debt Instrument [Line Items]
Total debt outstanding	$ 1,126,000	1,126,000
Debt instrument, interest rate, stated percentage	4.00%
Note payable to Tom George Yacht Group, unsecured and bearing interest at 5.5% per annum. The note requires quarterly interest payments, with a balloon payment of principal due on December 1, 2023
Debt Instrument [Line Items]
Total debt outstanding	$ 0	$ 2,056,000
Debt instrument, interest rate, stated percentage	5.50%