v3.25.1
Long-term Debt and Line of Credit - Summary of Long-term Debt and Line of Credit (Details) - USD ($)
 6 Months Ended
Mar. 31, 2025
Sep. 30, 2024
Debt Instrument [Line Items]    
Total debt outstanding $ 433,464,000 $ 430,306,000
Less current portion (net of debt issuance costs) (26,708,000) (7,874,000)
Less unamortized portion of debt issuance costs (6,271,000) (7,498,000)
Long-term debt, net of current portion and unamortized debt issuance costs 400,485,000 414,934,000
Term note payable to Truist Bank, secured and bearing interest at 7.55% at March 31, 2025 and 7.85% at September 30, 2024. The note requires quarterly principal payments commencing on December 31, 2022 and maturing with a full repayment on July 31, 2026    
Debt Instrument [Line Items]    
Total debt outstanding $ 375,469,000 $ 375,469,000
Debt instrument, interest rate, stated percentage 7.55% 7.85%
Revolving note payable for an amount up to $65.0 million to Truist Bank, secured and bearing interest at 7.54% at March 31, 2025 and 7.75% at September 30, 2024. The note requires full repayment on July 31, 2026    
Debt Instrument [Line Items]    
Total debt outstanding $ 55,936,000 $ 51,150,000
Debt instrument, interest rate, stated percentage 7.54% 7.75%
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 February 2030    
Debt Instrument [Line Items]    
Total debt outstanding $ 2,059,000 $ 2,561,000
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 February 2030 | 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 February 2030 | 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 was paid in full on December 1, 2024    
Debt Instrument [Line Items]    
Total debt outstanding $ 0 $ 1,126,000
Debt instrument, interest rate, stated percentage 4.00%