Derivative Financial Instruments - Summary of Outstanding Forward Foreign Currency Contracts by Currency (Detail) € in Thousands, £ in Thousands, $ in Thousands, $ in Thousands	Dec. 31, 2021 EUR (€)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2021 SGD ($)	Sep. 30, 2021 EUR (€)	Sep. 30, 2021 USD ($)	Sep. 30, 2021 GBP (£)	Sep. 30, 2021 SGD ($)
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	€ 15,900	18,044			€ 17,100	19,829
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		14,800	£ 10,983			15,400	£ 11,467
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		$ 5,500		$ 7,405		$ 4,900		$ 6,650