Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2024 |
Jun. 30, 2023 |
Jun. 30, 2024 |
Jun. 30, 2023 |
Sep. 30, 2023 |
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| Concentration Risk [Line Items] | |||||
| Restricted cash | $ 2,116 | $ 2,116 | $ 837 | ||
| Restricted investments | $ 17,016 | $ 17,016 | $ 15,079 | ||
| Revenues | Customer Concentration Risk | Various Departments of Transportation | |||||
| Concentration Risk [Line Items] | |||||
| Concentration risk percentage | 42.30% | 38.60% | 39.70% | 32.00% | |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as noncurrent. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cash restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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