Derivative Financial Instruments - Summary of Outstanding Forward Foreign Currency Contracts by Currency (Detail) € in Thousands, £ in Thousands, $ in Thousands, $ in Thousands	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Jun. 30, 2024 GBP (£)	Jun. 30, 2024 SGD ($)	Sep. 30, 2023 EUR (€)	Sep. 30, 2023 USD ($)	Sep. 30, 2023 GBP (£)	Sep. 30, 2023 SGD ($)
Foreign Exchange Contracts To Sell European Euro for US Dollar
Derivative [Line Items]
Fair value of forward foreign currency contracts to sell and buy foreign currency		$ 0				$ 0
Foreign Exchange Contracts To Sell European Euro for US Dollar | Foreign currency forward contracts | Short | Not Designated as Hedging Instrument
Derivative [Line Items]
Contract amount of forward foreign currency contracts	€ 7,900	8,447			€ 12,900	13,621
Foreign Exchange Contracts To Purchase British Pounds With US Dollars
Derivative [Line Items]
Fair value of forward foreign currency contracts to sell and buy foreign currency		0				0
Foreign Exchange Contracts To Purchase British Pounds With US Dollars | Foreign currency forward contracts | Short | Not Designated as Hedging Instrument
Derivative [Line Items]
Contract amount of forward foreign currency contracts		11,100	£ 8,764			13,100	£ 10,700
Foreign Exchange Contracts To Purchase Singapore Dollars With US Dollars
Derivative [Line Items]
Fair value of forward foreign currency contracts to sell and buy foreign currency		0				0
Foreign Exchange Contracts To Purchase Singapore Dollars With US Dollars | Foreign currency forward contracts | Short | Not Designated as Hedging Instrument
Derivative [Line Items]
Contract amount of forward foreign currency contracts		$ 4,200		$ 5,688		$ 6,300		$ 8,569