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Share-Based Compensation - Additional Information (Details) $ in Thousands | 1 Months Ended | 3 Months Ended | 9 Months Ended | 24 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Mar. 31, 2024 shares | Jun. 30, 2025 USD ($) installment shares | Jun. 30, 2024 USD ($) | Jun. 30, 2025 USD ($) installment shares | Jun. 30, 2024 USD ($) | Jun. 30, 2025 USD ($) installment shares | Sep. 30, 2024 USD ($) | May 31, 2021 shares | Sep. 30, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Compensation expense recorded upon vesting of awards | $ |  | $ 8,564 | $ 4,039 | $ 27,961 | $ 10,586 |  |  |  |
Class A Common Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Issuance of stock grant awards (in shares) |  |  |  | 136,917 |  |  |  |  |
Class B Common Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Issuance of stock grant awards (in shares) |  |  |  | 61,000 |  |  |  |  |
Market-Based Restricted Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Aggregate grant date fair value of shares awarded | $ |  | 9,800 |  | $ 9,800 |  | $ 9,800 |  |  |
Compensation expense recorded upon vesting of awards | $ |  | 0 |  | $ 9,800 |  |  |  |  |
Market-Based Restricted Stock | Class A Common Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  | 79,000 |  |  |  |  |
Market-Based Restricted Stock | Class B Common Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  | 61,000 |  |  |  |  |
Performance Shares |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Aggregate grant date fair value of shares awarded | $ |  | $ 4,100 |  | $ 4,100 |  | $ 4,100 |  |  |
Unrecognized compensation expense, period for recognition (years) |  |  |  | 2 years 3 months 18 days |  |  |  |  |
Performance Shares | Class A Common Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Forecasted unvested restricted shares of Class A common stock (in shares) |  | 366,793 |  | 366,793 |  | 366,793 |  |  |
Unrecognized compensation expense at fiscal year-end | $ |  | $ 5,800 |  | $ 5,800 |  | $ 5,800 |  |  |
Shares issued (in shares) |  |  |  | 215,917 |  |  |  |  |
Performance Shares | Class A Common Stock | Certain members of management |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Granted (in shares) |  |  |  | 73,603 |  |  |  |  |
Forecasted unvested restricted shares of Class A common stock (in shares) |  | 55,202 |  | 55,202 |  | 55,202 |  |  |
Performance Shares | Class B Common Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Shares issued (in shares) |  |  |  | 61,000 |  |  |  |  |
Performance Shares | Class B Common Stock | Certain members of management |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Shares issued (in shares) |  |  |  | 61,000 |  |  |  |  |
Liability classified awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Compensation expense recorded upon vesting of awards | $ |  | $ 4,076 | 1,092 | $ 5,916 | 1,974 |  |  |  |
Current liability for cash-settled restricted stock units | $ |  | 7,700 |  | 7,700 |  | $ 7,700 | $ 3,700 |  |
Liability classified awards | Class A Common Stock |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Compensation expense recorded upon vesting of awards | $ |  | 4,100 |  | $ 5,900 |  |  |  |  |
Unrecognized compensation expense, period for recognition (years) |  |  |  | 3 years 2 months 12 days |  |  |  |  |
Shares issued (in shares) |  |  |  | 80,614 |  |  |  |  |
Unrecognized compensation expense | $ |  | $ 9,500 |  | $ 9,500 |  | $ 9,500 |  |  |
Requisite service period, number of equal annual installments | installment |  | 4 |  | 4 |  | 4 |  |  |
Employee stock purchase plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Maximum number of shares offered under the ESPP (in shares) |  |  |  |  |  |  |  | 1,000,000 |
Compensation expense recorded upon vesting of awards | $ |  | $ 584 | $ 54 | $ 1,098 | $ 380 |  |  |  |
Shares issued (in shares) |  |  |  |  |  | 84,601 |  |  |
Minimum | Performance Shares |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Percentage of final number of of common stock issuable upon vesting of performance stock units |  |  |  | 0 |  |  |  |  |
Maximum | Performance Shares |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Percentage of final number of of common stock issuable upon vesting of performance stock units |  |  |  | 1.50 |  |  |  |  |
Percentage increase (decrease) of awards granted due to total shareholder return ranking |  |  |  | 0.15 |  |  |  |  |
Equity Incentive Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Maximum number of shares offered under the ESPP (in shares) |  |  |  |  |  |  |  |  | 2,000,000
Additional shares authorized (in shares) | 1,000,000 |  |  |  |  |  |  |  |
Shares available for issuance (in shares) |  | 901,350 |  | 901,350 |  | 901,350 |  |  |
Equity Incentive Plan | Performance Shares |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Compensation expense recorded upon vesting of awards | $ |  | $ 1,100 |  | $ 2,800 |  |  |  |  |
Restricted Stock Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Maximum number of shares offered under the ESPP (in shares) | 2,000,000 |  |  |  |  |  |  |  |
Shares available for issuance (in shares) |  | 1,891,000 |  | 1,891,000 |  | 1,891,000 |  |  |

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