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Equity-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions							12 Months Ended
	May 17, 2022	Nov. 18, 2021	Nov. 15, 2021	Nov. 19, 2020	Nov. 14, 2020	Nov. 14, 2019	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Mar. 10, 2020	Oct. 22, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted, weighted average exercise price							$ 15.04
Number of shares exercised							1,000
Equity-based compensation							$ 18.9	$ 19.7	$ 23.6
Unrecognized compensation cost							$ 36.2	$ 25.6	$ 36.2
Unrecognized compensation cost, weighted average recognition period							1 year 3 months 18 days	1 year 3 months 18 days	1 year 3 months 18 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period								4 years
Units granted							1,613,000
Units forfeited or canceled							199,000
Stock options weighted average grant date fair value								$ 11.85
Non-cash equity-based compensation expense over the requisite service period							$ 16.3
Granted, weighted average exercise price							$ 11.85
Number of shares exercised							428,000
Common stock shares issued							1,613,000
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units granted	403,000						403,000
Units forfeited or canceled	0						0
Weighted average exercise price	$ 16.51
Non-cash equity-based compensation expense over the requisite service period	$ 6.7
Granted, weighted average exercise price	$ 12.41						$ 12.41
Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units forfeited or canceled							26,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period				4 years
Stock options weighted average grant date fair value		$ 6.84
Weighted average exercise price		$ 15.04
Non-cash equity-based compensation expense over the requisite service period		$ 4.7
Number of shares forfeited							310,000
Number of shares exercised							1,000
Common stock shares issued		783,000
Amended and Restated 2018 Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares of common stock that may be issued										18,650,000
ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares available for sale											1,100,000
Common stock shares issued			112,000		120,000	172,000