Investments - Trading Investments Details (Detail) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Sep. 30, 2022 |
Sep. 30, 2021 |
|
| Investments [Line Items] | ||
| Cost | $ 4 | $ 4 |
| Gross Unrealized Gains | 24 | 24 |
| Gross Unrealized Losses | (19) | (18) |
| Total | 9 | 10 |
| Mutual Fund Investments [Member] | ||
| Investments [Line Items] | ||
| Cost | 4 | 4 |
| Gross Unrealized Gains | 24 | 24 |
| Gross Unrealized Losses | (19) | (18) |
| Total | $ 9 | $ 10 |