Long-Term Debt and Bank Facility Borrowings - Company's Debt (Detail) - USD ($) $ in Thousands		Mar. 31, 2023	Sep. 30, 2022
Debt Instrument [Line Items]
Long-term debt, carrying Amount		$ 225,895	$ 184,360
Current maturities of long-term debt, carrying Amount		86,436	32,651
Long-term debt	[1]	139,459	151,709
Long-term debt, fair value	[2]	226,686	185,276
Current maturities of long-term debt, fair value	[2]	86,436	32,651
Long-term portion of debt, fair value	[1],[2]	140,250	152,625
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility borrowings, carrying Amount		69,936	20,276
Credit facility borrowings, fair value	[2]	69,936	20,276
Term Loan
Debt Instrument [Line Items]
Long-term debt, carrying Amount	[1]	155,959	164,084
Long-term debt, fair value	[1],[2]	$ 156,750	$ 165,000

[1] Carrying amounts are net of unamortized debt issuance costs of $0.8 million as of March 31, 2023 and $0.9 million as of September 30, 2022

[2] The face amount of the Company’s variable rate long-term debt approximates fair value.