Derivative Instruments - Summary of Cash Flow Hedges (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total gain recognized		$ 2,665		$ 5,245
Cash Flow Hedging | Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total gain recognized	$ 2,287	(7,825)	$ 4,960	(5,245)
Cash Flow Hedging | Designated as Hedging Instrument | Interest rate swap contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total gain recognized	2,287	(7,561)	4,960	(5,113)
Cash Flow Hedging | Designated as Hedging Instrument | Foreign currency forward contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total gain recognized	$ 0	$ (264)	$ 0	$ (132)