Derivatives and Hedging Activities - Schedule of Effect of Cash Flow Hedge Accounting on Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in OCI on Derivative	$ (475)	$ 6,826	$ 193	$ 8,965
Designated as Hedging Instrument [Member] \| Cash Flow Hedges of Interest Rate Risk [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(2,768)	6,992	(3,934)	5,546
Gain (Loss) Reclassified from Accumulated OCI into Income	$ 2,293	$ (166)	$ 4,127	$ (402)
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Interest Expense	Interest Expense	Interest Expense	Interest Expense
Designated as Hedging Instrument [Member] \| Interest Rate Products [Member] \| Cash Flow Hedges of Interest Rate Risk [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in OCI on Derivative	$ (2,768)	$ 6,992	$ (3,934)	$ 5,546
Gain (Loss) Reclassified from Accumulated OCI into Income	$ 2,293	$ (166)	$ 4,127	$ (402)

Indicates line item in statement of income or comprehensive income that includes gain (loss) from effective portion of derivative instrument reclassified from accumulated other comprehensive income (AOCI) into income.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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No definition available.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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