Share-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to unvested share-based compensation arrangements	$ 4,400
Unrecognized compensation cost, period for recognition	1 year 8 months 12 days
Share-based compensation expense	$ 2,800	$ 3,100	$ 4,400
Repurchased shares, value	$ 455	$ 1,486	$ 586
Common Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repurchased shares, shares	147,108	155,174	142,439
Repurchased shares, value	$ 500	$ 1,500	$ 600
Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vesting period	1 year
Restricted Stock Units [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vesting period	3 years
Restricted Stock Units [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vesting period	5 years

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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