Long-Term Debt and Bank Facility Borrowings - Company's Debt (Detail) - USD ($) $ in Thousands		Mar. 31, 2025	Sep. 30, 2024
Debt Instrument [Line Items]
Long-term debt, carrying Amount		$ 220,842	$ 208,816
Current maturities of long-term debt, carrying Amount		43,348	21,005
Long-term debt	[1]	177,494	187,811
Long-term debt, fair value	[2]	221,848	210,005
Current maturities of long-term debt, fair value	[2]	43,348	21,005
Long-term portion of debt, fair value	[1],[2]	178,500	189,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility borrowings, carrying Amount		22,348	5
Credit facility borrowings, fair value	[2]	22,348	5
Term Loan
Debt Instrument [Line Items]
Long-term debt, carrying Amount	[1]	198,494	208,811
Long-term debt, fair value	[1],[2]	$ 199,500	$ 210,000

[1] Carrying amounts are net of unamortized debt issuance costs of $1.0 million as of March 31, 2025 and $1.2 million as of September 30, 2024

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