Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 01, 2020	Mar. 31, 2018	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2019	Aug. 31, 2021	Sep. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from issuance of common stock					$ 37.1	$ 0.0
Payments of stock issuance costs					$ 1.1	$ 0.0
Weighted-average grant date fair value of options (in dollars per share)					$ 22.51	$ 39.69
Intrinsic value of options exercised					$ 0.9	$ 7.6
Restricted stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total fair value of RSUs vested					6.2	0.9
Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incentive units authorized for issuance (in shares)		6,199,477
Incentive Plan | Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense					54.9	$ 55.4
Incentive Plan | Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense			$ 16.7	$ 18.8
Compensation expense not yet recognized			$ 67.3		$ 67.3
Compensation expense not yet recognized, period of recognition (in years)					1 year 8 months 12 days
Incentive Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based award, vesting period (in years)		1 year
Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)									1,277,181
Share-based award, vesting period (in years)		4 years
2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)									4,067,007
Common stock, shares remained available for purchase (in shares)			2,111,046		2,111,046
Annual increase in reserved shares as percentage of outstanding common stock							4.00%
2018 Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual increase in reserved shares of common stock (in shares)							4,989,593
2018 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)									311,850
Common stock reserved for issuance represented as percentage on outstanding common stock	1.00%
Common stock, shares remained available for purchase (in shares)			2,440,434		2,440,434
Common stock, shares issued (in shares)					78,528	24,898
2018 ESPP | Incentive Plan | Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense			$ 0.2	$ 0.2	$ 0.7	$ 0.5
Equity Distribution Agreement | At-the-Market Offering | Piper Sandler and Cantor
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock aggregate offering price								$ 300.0
Shares issued and sold (in shares)			1,449,275
Proceeds from issuance of common stock			$ 36.0
Payments of stock issuance costs			$ 1.1