Consolidated Statements of Stockholders' Equity and Mezzanine Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock [Member]	Preferred Stock
Balance at Sep. 30, 2020	$ 1,271.5	$ 1.0	$ 1,467.8	$ (187.9)	$ (6.9)	$ (2.5)	$ 0.0
Balance, Shares at Sep. 30, 2020		104.9					0.0
Net income (loss)	46.3			46.3
Other comprehensive income, net of tax	5.4				5.4
Issuance of common stock	1.7	$ 0.1	1.6
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)	$ 0.0
Balance, Shares at Sep. 30, 2021		105.2					0.0
Net income (loss)	14.0			14.0
Other comprehensive income, net of tax	3.5				3.5
Issuance of common stock	1.5		1.5
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)	$ 0.0
Balance, Shares at Sep. 30, 2022		105.7					0.0
Net income (loss)	(7.7)			(7.7)
Other comprehensive income, net of tax	15.1				15.1
Issuance of common stock	2.4		2.4
Issuance of common stock, Shares		0.9
Equity-based compensation	22.1		22.1			(2.2)
Repurchase of common stock and distributions	(2.2)
Issuance of Series A preferred stock, net of issuance costs							$ 495.0
Issuance of Series A preferred stock, net of issuance costs, Shares							0.5
Dividends on Series A convertible preferred shares	3.2		3.2				$ 3.2
Balance at Sep. 30, 2023	$ 1,243.3	$ 1.1	$ 1,530.8	$ (135.3)	$ 17.1	$ (170.4)	$ 498.2
Balance, Shares at Sep. 30, 2023		106.6					0.5