Stock-Based Employee Benefit Plans - Summary of Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2022 USD ($) $ / shares shares
Shares
Outstanding at September 30, 2019 (in shares) | shares	226
Granted (in shares) | shares	23
Exercised (in shares) | shares	(36)
Forfeited (in shares) | shares	(4)
Outstanding at September 30, 2020 (in shares) | shares	209
Options exercisable at September 30, 2020 (in shares) | shares	159
Vested and expected to vest at September 30, 2020 (in shares) | shares	207
Weighted- average Exercise Price
Outstanding at September 30, 2019 (in dollars per share) | $ / shares	$ 205.90
Granted (in dollars per share) | $ / shares	451.70
Exercised (in dollars per share) | $ / shares	87.84
Forfeited (in dollars per share) | $ / shares	523.43
Outstanding at September 30, 2020 (in dollars per share) | $ / shares	247.56
Options exercisable at September 30, 2020 (in dollars per share) | $ / shares	214.74
Vested and expected to vest at September 30, 2020 (in dollars per share) | $ / shares	$ 246.35
Weighted- average Remaining Contractual Term
Outstanding at September 30, 2022	3 years 3 months 10 days
Exercisable at September 30, 2022	2 years 9 months 25 days
Vested and expected to vest at September 30, 2018	3 years 3 months 7 days
Aggregate Intrinsic Value
Outstanding at September 30, 2022 | $	$ 36,373
Exercisable at September 30, 2022 | $	32,118
Vested and expected to vest at September 30, 2017 | $	$ 36,344