Long-Term Debt and Bank Facility Borrowings - Company's Debt (Detail) - USD ($) $ in Thousands		Dec. 31, 2024	Sep. 30, 2024
Debt Instrument [Line Items]
Long-term debt, carrying Amount		$ 211,500	$ 208,816
Current maturities of long-term debt, carrying Amount		28,830	21,005
Long-term debt	[1]	182,670	187,811
Long-term debt, fair value	[2]	212,580	210,005
Current maturities of long-term debt, fair value	[2]	28,830	21,005
Long-term portion of debt, fair value	[1],[2]	183,750	189,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility borrowings, carrying Amount		7,830	5
Credit facility borrowings, fair value	[2]	7,830	5
Term Loan
Debt Instrument [Line Items]
Long-term debt, carrying Amount	[1]	203,670	208,811
Long-term debt, fair value	[1],[2]	$ 204,750	$ 210,000

[1] Carrying amounts are net of unamortized debt issuance costs of $1.1 million as of December 31, 2024 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.