Long-Term Debt and Bank Facility Borrowings - Company's Debt (Parenthetical) (Detail) - USD ($) $ in Thousands		6 Months Ended
		Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2022
Debt Instrument [Line Items]
Long term debt		$ 225,895		$ 184,360
Loan repayment		8,250	$ 11,365
Term Loan
Debt Instrument [Line Items]
Unamortized debt issuance costs		800		900
Long term debt	[1]	$ 155,959		$ 164,084

[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