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Stock-Based Compensation (Tables) | 12 Months Ended
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Sep. 30, 2025
Share-Based Payment Arrangement, Noncash Expense [Abstract] |
Schedule Of Assumptions In Determining The Fair Value Of Shares Issued Under The Employee Stock Purchase Plan | In determining the fair value of the right to purchase under the Employee Stock Purchase Plan, the Company uses the Black-Scholes option pricing model that employs the following key assumptions:
|  | Employee Stock Purchase Plan Years Ended September 30,
|  | 2025 |  | 2024 |  | 2023
Volatility |  | 28.85% - 29.40% |  | 18.19% - 20.32% |  | 33.02% - 38.15%
Expected term (in years) |  | 0.5 |  | 0.5 |  | 0.5
Dividend yield |  | — |  |  | — |  |  | — |
Risk-free interest rate |  | 4.28% - 4.98% |  | 5.28% - 5.52% |  | 3.18% - 4.90%
Schedule Of Summary Of Restricted Stock Unit Activity | A summary of restricted stock unit activity under the Plan is as follows:
|  | Performance Stock Units |  | Restricted Stock Units
|  | Outstanding Performance Stock Units |  | Weighted Average Grant Date Fair Value |  | Outstanding Restricted Stock Units |  | Weighted Average Grant Date Fair Value
Balance, September 30, 2024 |  | 213,776 |  |  | $ | 155.63 |  |  | 1,312,328 |  |  | $ | 158.22 |
Units granted |  | 120,235 |  |  | 248.47 |  |  | 1,167,667 |  |  | 255.09 |
Units vested |  | (117,333) |  |  | 174.32 |  |  | (1,058,085) |  |  | 174.19 |
Units cancelled |  | (32,955) |  |  | 170.83 |  |  | (224,382) |  |  | 181.40 |
Balance, September 30, 2025 |  | 183,723 |  |  | $ | 220.40 |  |  | 1,197,528 |  |  | $ | 234.22 |
Schedule of Share-Based Payment Award, Performance-based Awards, Valuation Assumptions | In determining the fair value of the portion of the performance awards based on Total Shareholder Return, the Company uses a Monte Carlo simulation model that employs the following key assumptions:
|  | Performance Awards based on Total Shareholder Return Years Ended September 30,
|  | 2025 |  | 2024 |  | 2023
Volatility |  | 24.06% - 30.78% |  | 22.60% - 32.35% |  | 31.74% - 40.59%
Expected term (in years) |  | 0.91 - 2.91 |  | 0.91 - 2.91 |  | 0.91 - 2.91
Dividend yield |  | — |  |  | — |  |  | — |
Risk-free interest rate |  | 4.14% - 4.26% |  | 4.72% - 5.32% |  | 4.44% - 4.66%
Grant-date fair value per share |  | $339.61 - $346.95 |  | $192.58 - $210.37 |  | $157.36 - $194.41
Schedule of Nonvested Restricted Stock Units Activity | As of September 30, 2025, the following annual equity grants for executive officers or a portion thereof are outstanding:
Grant Date | RSUs Granted | Vesting Schedule | Vesting Period | Date Fully Vested
November 1, 2024 | 165,912 | Quarterly, Annually | 3 years | November 1, 2027
November 1, 2023 | 206,560 | Quarterly, Annually | 3 years | November 1, 2026
November 1, 2022 | 240,808 | Quarterly, Annually | 3 years | November 1, 2025
Schedule Of Stock Option Activity | A summary of stock option activity under all of the Company’s plans is as follows:
|  | Options Outstanding
|  | Number of Shares |  | Weighted Average Exercise Price per Share
Balance, September 30, 2024 |  | 54,090 |  |  | $ | 39.36 |
Options granted |  | — |  |  | — |
Options exercised |  | (25,818) |  |  | 37.28 |
Options cancelled |  | (792) |  |  | 26.52 |
Balance, September 30, 2025 |  | 27,480 |  |  | $ | 41.69 |
Schedule Of Outstanding Stock Options Currently Exercisable, Vested And Expected To Vest | A summary of options outstanding that are exercisable and that have vested and are expected to vest as of September 30, 2025 is as follows:
|  | Number of Shares |  | Weighted Average Remaining Contractual Life (in Years) |  | Weighted Average Exercise Price per Share |  | Aggregate Intrinsic Value(1)
|  |  |  |  |  |  |  | (In thousands)
Stock options outstanding |  | 27,480 |  |  | 3.50 |  | $ | 41.69 |  |  | $ | 7,736 |
Exercisable |  | 27,480 |  |  | 3.50 |  | $ | 41.69 |  |  | $ | 7,736 |
Vested and expected to vest |  | 27,480 |  |  | 3.50 |  | $ | 41.69 |  |  | $ | 7,736 |
(1)Aggregate intrinsic value represents the difference between the fair value of the Company’s common stock underlying these options at September 30, 2025 and the related exercise prices.
Schedule Of Equity Based Awards (Including Stock Options And Restricted Stock Units) | As of September 30, 2025, equity based awards (including stock options and restricted stock units) are available for future issuance as follows:
|  | Awards Available for Grant
Balance, September 30, 2024 | 3,952,900 |
Granted | (1,287,902) |
Cancelled | 262,653 |
Additional shares reserved (terminated), net | (5,316) |
Balance, September 30, 2025 | 2,922,335 |

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