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Stock-Based Compensation - Narrative (Details) - USD ($) |  | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Oct. 31, 2023 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021 | Feb. 01, 2023 | Oct. 01, 2021 | Jan. 22, 2021 | Jan. 24, 2020 | May 08, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Share-based Payment Arrangement, Expense |  | $ 236,700,000 | $ 249,200,000 | $ 243,300,000 |  |  |  |  |
Share-based Payment Arrangement, Expense, Tax Benefit |  | 44,700,000 | $ 47,300,000 | $ 44,100,000 |  |  |  |  |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount |  | $ 162,700,000 |  |  |  |  |  |  |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition |  | 2 years |  |  |  |  |  |  |
Expected term |  | 6 months | 6 months | 6 months |  |  |  |  |
Weighted Average Grant Date Fair Value |  | $ 144.78 | $ 206.13 | $ 145.89 |  |  |  |  |
Fair market value of restricted stock vested |  | $ 195,900,000 | $ 262,400,000 | $ 261,900,000 |  |  |  |  |
Total intrinsic value of options exercised |  | $ 6,900,000 | $ 25,600,000 | $ 25,600,000 |  |  |  |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Equity Instruments Other than Options, Grants in Period | 1,256,510 |  |  |  |  |  |  |  |
Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Award vesting period |  | 2 years | 2 years | 2 years |  |  |  |  |
Two Thousand Eleven Employee Stock Purchase Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  | 12,000,000 |  |  |  |  |  |  |
Percentage of base compensation for which employees can acquire shares of common stock |  | 15.00% |  |  |  |  |  |  |
Maximum shares allowed for purchase by employee in period |  | 10,000 |  |  |  |  |  |  |
Maximum aggregate fair value of stock that an employee may purchase |  | $ 25,000 |  |  |  |  |  |  |
Expected term |  | 6 months |  |  |  |  |  |  |
Percentage of common stock lesser of the fair market value |  | 85.00% |  |  |  |  |  |  |
Number of Shares Authorized |  | 2,444,575 |  |  |  |  |  |  |
Nginx Acquisition Equity Incentive Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  |  |  |  |  | 183,061
Vesting rate of stock options and awards upon certain changes in ownership control |  | 50.00% |  |  |  |  |  |  |
Nginx Acquisition Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Outstanding stock units |  | 19 |  |  |  |  |  |  |
Nginx, Inc. 2011 Share Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  |  |  |  |  | 302,634
Nginx, Inc. 2011 Share Plan [Member] | Share-based Payment Arrangement, Option [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Shares available for purchase under stock option plan |  | 6,010 |  |  |  |  |  |  |
Shape Acquisition Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  |  |  |  | 450,000 |
Vesting rate of stock options and awards upon certain changes in ownership control |  | 50.00% |  |  |  |  |  |  |
Shape Acquisition Plan [Member] | Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Outstanding stock units |  | 20,754 |  |  |  |  |  |  |
Shape 2011 Share Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  |  |  |  | 501,085 |
Shape 2011 Share Plan [Member] | Share-based Payment Arrangement, Option [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Shares available for purchase under stock option plan |  | 51,144 |  |  |  |  |  |  |
Volterra Acquisition Equity Incentive Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  |  |  | 140,000 |  |
Vesting rate of stock options and awards upon certain changes in ownership control |  | 50.00% |  |  |  |  |  |  |
Volterra Acquisition Equity Incentive Plan | Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Outstanding stock units |  | 39,472 |  |  |  |  |  |  |
Volterra 2017 Stock Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  |  |  | 261,696 |  |
Volterra 2017 Stock Plan | Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Outstanding stock units |  | 7,171 |  |  |  |  |  |  |
Volterra 2017 Stock Plan | Share-based Payment Arrangement, Option [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Shares available for purchase under stock option plan |  | 46,778 |  |  |  |  |  |  |
Threat Stack Acquisition Equity Incentive Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  |  | 35,000 |  |  |
Vesting rate of stock options and awards upon certain changes in ownership control |  | 50.00% |  |  |  |  |  |  |
Threat Stack Acquisition Equity Incentive Plan | Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Outstanding stock units |  | 6,915 |  |  |  |  |  |  |
Lilac Acquisition Equity Incentive Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  | 55,000 |  |  |  |
Vesting rate of stock options and awards upon certain changes in ownership control |  | 50.00% |  |  |  |  |  |  |
Lilac Acquisition Equity Incentive Plan | Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Outstanding stock units |  | 47,904 |  |  |  |  |  |  |
Shares Issued in Period |  | 47,904 |  |  |  |  |  |  |
Lilac Cloud 2018 Equity Incentive Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  |  |  |  | 4,485 |  |  |  |
Lilac Cloud 2018 Equity Incentive Plan | Share-based Payment Arrangement, Option [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Shares available for purchase under stock option plan |  | 1,936 |  |  |  |  |  |  |
Shares Issued in Period |  | 2,051 |  |  |  |  |  |  |
Two Thousand Fourteen Equity Incentive Plan [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common stock reserved for issuance |  | 27,880,000 |  |  |  |  |  |  |
Vesting rate of stock options and awards upon certain changes in ownership control |  | 50.00% |  |  |  |  |  |  |
Number of Shares Authorized |  | 5,287,273 |  |  |  |  |  |  |
Two Thousand Fourteen Equity Incentive Plan [Member] | Performance Shares [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Equity Instruments Other than Options, Grants in Period |  | 131,491 |  |  |  |  |  |  |
Outstanding stock units |  | 199,918 | 208,116 |  |  |  |  |  |
Shares Issued in Period |  | 131,491 |  |  |  |  |  |  |
Weighted Average Grant Date Fair Value |  | $ 159.37 | $ 169.99 |  |  |  |  |  |
Two Thousand Fourteen Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Equity Instruments Other than Options, Grants in Period |  | 1,448,427 |  |  |  |  |  |  |
Outstanding stock units |  | 1,225,386 | 1,137,619 |  |  |  |  |  |
Shares Issued in Period |  | 1,448,427 |  |  |  |  |  |  |
Weighted Average Grant Date Fair Value |  | $ 156.89 | $ 184.59 |  |  |  |  |  |

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