Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance at Sep. 30, 2019	$ 1,283.8	$ 1.0	$ 1,441.8	$ (146.3)	$ (11.7)	$ (1.0)
Balance, Shares at Sep. 30, 2019		104.7
Net income (loss)	(41.6)			(41.6)
Other comprehensive income, net of tax	4.8				4.8
Capital contributions and issuance of common stock	2.4		2.4
Capital contributions and issuance of common stock, Shares		0.2
Equity-based compensation	23.6		23.6
Repurchase of common stock and distributions	(1.5)					(1.5)
Balance at Sep. 30, 2020	1,271.5	$ 1.0	1,467.8	(187.9)	(6.9)	(2.5)
Balance, Shares at Sep. 30, 2020		104.9
Net income (loss)	46.3			46.3
Other comprehensive income, net of tax	5.4				5.4
Capital contributions and issuance of common stock	1.7	$ 0.1	1.6
Capital contributions and issuance of common stock, Shares		0.3
Equity-based compensation	19.7		19.7
Repurchase of common stock and distributions	(1.9)					(1.9)
Balance at Sep. 30, 2021	1,342.7	$ 1.1	1,489.1	(141.6)	(1.5)	(4.4)
Balance, Shares at Sep. 30, 2021		105.2
Net income (loss)	14.0			14.0
Other comprehensive income, net of tax	3.5				3.5
Capital contributions and issuance of common stock	1.5		1.5
Capital contributions and issuance of common stock, Shares		0.5
Equity-based compensation	18.9		18.9
Repurchase of common stock and distributions	(163.8)					(163.8)
Balance at Sep. 30, 2022	$ 1,216.8	$ 1.1	$ 1,509.5	$ (127.6)	$ 2.0	$ (168.2)
Balance, Shares at Sep. 30, 2022		105.7