Long-term Debt and Line of Credit - Summary of Long-term Debt and Line of Credit (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Debt Instrument [Line Items]
Total debt outstanding	$ 465,140,000	$ 452,355,000
Less current portion (net of current debt issuance costs)	(29,324,000)	(21,642,000)
Less unamortized portion of debt issuance costs	(7,377,000)	(9,551,000)
Long-term debt, net of current portion and unamortized debt issuance costs	428,439,000	421,162,000
Term Note Payable on August 9, 2027
Debt Instrument [Line Items]
Total debt outstanding	$ 428,313,000	$ 445,000,000
Debt instrument, interest rate, stated percentage	7.53%	5.31%
Revolving Note Payable
Debt Instrument [Line Items]
Total debt outstanding	$ 30,000,000	$ 0
Debt instrument, interest rate, stated percentage	7.50%
Line of credit facility, maximum borrowing capacity	$ 65,000,000
Note Payable Due On September 2028
Debt Instrument [Line Items]
Total debt outstanding	$ 3,645,000	4,173,000
Note Payable Due On September 2028 | Minimum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	0.00%
Debt instrument, periodic payment	$ 100,000
Note Payable Due On September 2028 | Maximum
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	10.80%
Debt instrument, periodic payment	$ 3,100,000
Note Payable 5.5% Due on December 1, 2023
Debt Instrument [Line Items]
Total debt outstanding	$ 2,056,000	2,056,000
Debt instrument, interest rate, stated percentage	5.50%
Note payable, 4.0% 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%