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Equity-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions |  |  |  | 9 Months Ended |
--- | --- | --- | --- | --- | ---
Nov. 19, 2020 | Nov. 16, 2020 | Nov. 14, 2019 | Jun. 30, 2021 | Oct. 22, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |
Stock options issued to holders of units, weighted average exercise price | $ 13.78 |  |  |  |
Stock options weighted average grant date fair value | $ 6.71 |  |  |  |
Non-cash equity-based compensation expense over the requisite service period | $ 4.1 |  |  |  |
Unamortized value of outstanding stock-based compensation |  |  |  | $ 29.5 |
Unamortized value of outstanding stock-based compensation, weighted average remaining life |  |  |  | 1 year 3 months 18 days |
ESPP |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |
Common stock shares available for sale |  |  |  |  | 1,100,000
Common stock shares issued |  | 120,000 | 172,000 |  |
Restricted Stock Units (RSUs) |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |
Issued shares of common stock | 733,000 |  |  |  |
Weighted average exercise price | $ 13.78 |  |  |  |
Vesting period | 4 years |  |  |  |
Vesting terms |  |  |  | anniversary of the grant date |
Non-cash equity-based compensation expense over the requisite service period | $ 8.9 |  |  |  |
Stock Options |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |
Vesting period | 4 years |  |  |  |
Stock options issued to holders of units | 686,000 |  |  |  |

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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition 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 Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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