Equity - Schedule of Non-Vested Restricted Stock Units Compensation (Detail) - USD ($) $ in Thousands	9 Months Ended
Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expected compensation expense related to RSUs	$ 1,054	$ 1,341
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total expected compensation expense related to RSUs	16,056
Recognized compensation expense related to RSUs	(13,965)
Unrecognized compensation expense related to RSUs	$ 2,091
Weighted average remaining years to expense for RSUs	2 years 6 months

Amount of cost capitalized for award under share-based payment arrangement.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Amount of noncash expense for share-based payment arrangement.

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