Significant Accounting Policies (Details) - USD ($) |
3 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Sep. 30, 2021 |
|
| Concentration Risk [Line Items] | |||
| Short-term restricted cash | $ 6,568,000 | $ 0 | |
| Long-term restricted cash | $ 1,728,000 | $ 0 | |
| Revenues | Customer Concentration Risk | Public | |||
| Concentration Risk [Line Items] | |||
| Concentration risk percentage | 61.00% | 59.40% | |
| Revenues | Customer Concentration Risk | Private | |||
| Concentration Risk [Line Items] | |||
| Concentration risk percentage | 39.00% | 40.60% | |
| Revenues | Customer Concentration Risk | Department of Transportation | |||
| Concentration Risk [Line Items] | |||
| Concentration risk percentage | 33.50% | 27.80% | |
| Revenues | Customer Concentration Risk | Alabama Department of Transportation | |||
| Concentration Risk [Line Items] | |||
| Concentration risk percentage | 10.10% | 7.20% | |
| Revenues | Customer Concentration Risk | Florida Department of Transportation | |||
| Concentration Risk [Line Items] | |||
| Concentration risk percentage | 10.00% | 8.80% | |
| X | ||||||||||
- 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. No definition available.
|
| X | ||||||||||
- 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
|
| X | ||||||||||
- 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
|
| X | ||||||||||
- Definition Amount of cash restricted as to withdrawal or usage, classified as noncurrent. 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
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|