Fair Value Of Financial Instruments - Summary of Carrying Values and the Estimated Fair Values of the Debt Financial Instruments (Detail) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Schedule of carrying values and the estimated fair values of the debt financial instruments [Line Items]
Debt instrument maturity date	May 05, 2024
Revolving Credit Facility [Member]
Schedule of carrying values and the estimated fair values of the debt financial instruments [Line Items]
Debt instrument maturity date	Mar. 31, 2026
Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of carrying values and the estimated fair values of the debt financial instruments [Line Items]
Loans payable	$ 467,654	$ 467,654
Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member] | Revolving Credit Facility [Member]
Schedule of carrying values and the estimated fair values of the debt financial instruments [Line Items]
Loans payable	40,000
Estimated Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
Schedule of carrying values and the estimated fair values of the debt financial instruments [Line Items]
Loans payable	463,071	$ 467,420
Estimated Fair Value [Member] | Fair Value, Inputs, Level 2 [Member] | Revolving Credit Facility [Member]
Schedule of carrying values and the estimated fair values of the debt financial instruments [Line Items]
Loans payable	$ 40,000