Fair Value Measurements - Narrative (Details) - USD ($) |
1 Months Ended | 12 Months Ended | |
|---|---|---|---|
Aug. 31, 2020 |
Sep. 30, 2020 |
Sep. 30, 2019 |
|
| Fair Value Disclosures [Abstract] | |||
| Assets held for sale, fair value | $ 0 | $ 0 | |
| MSP termination benefits payment | $ 5,175,000 | 5,175,000 | |
| Deferred retirement benefit | $ 0 | ||
| Estimated discount rate | 4.08% |
| X | ||||||||||
- Definition Defined benefit plan benefit obligation termination benefits paid. No definition available.
|
| X | ||||||||||
- Definition Fair value portion of assets classified as held for sale. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of liability for retirement benefits, classified as other. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|