Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Preferred Shares
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)	(40.9)			(40.9)
Other comprehensive income, net of tax	(2.1)				(2.1)
Capital contributions and issuance of common stock	1.4		1.4
Capital contributions and issuance of common stock, Shares		0.7
Equity-based compensation	11.9		11.9
Repurchase of common stock and distributions	(1.2)					(1.2)
Balance at Mar. 31, 2023	1,185.9	$ 1.1	1,522.8	(168.5)	(0.1)	(169.4)	$ 0.0
Balance, Shares at Mar. 31, 2023		106.4					0.0
Balance at Dec. 31, 2022	1,201.3	$ 1.1	1,516.5	(146.5)	(0.4)	(169.4)	$ 0.0
Balance, Shares at Dec. 31, 2022		106.4					0.0
Net income (loss)	(22.0)			(22.0)
Other comprehensive income, net of tax	0.3				0.3
Equity-based compensation	6.3		6.3
Balance at Mar. 31, 2023	1,185.9	$ 1.1	1,522.8	(168.5)	(0.1)	(169.4)	$ 0.0
Balance, Shares at Mar. 31, 2023		106.4					0.0
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
Net income (loss)	17.3			17.3
Other comprehensive income, net of tax	(6.8)				(6.8)
Capital contributions and issuance of common stock	0.4		0.4
Capital contributions and issuance of common stock, Shares		1.3
Equity-based compensation	10.0		10.0
Repurchase of common stock and distributions	(2.5)					(2.5)
Series A Preferred Stock dividends	(17.8)		(17.8)				$ 8.9
Balance at Mar. 31, 2024	1,243.9	$ 1.1	1,523.4	(118.0)	10.3	(172.9)	$ 507.1
Balance, Shares at Mar. 31, 2024		107.9					0.5
Balance at Dec. 31, 2023	1,208.1	$ 1.1	1,527.4	(151.7)	4.2	(172.9)	$ 507.1
Balance, Shares at Dec. 31, 2023		107.8					0.5
Net income (loss)	33.7			33.7
Other comprehensive income, net of tax	6.1				6.1
Capital contributions and issuance of common stock, Shares		0.1
Equity-based compensation	4.9		4.9
Series A Preferred Stock dividends	(8.9)		(8.9)
Balance at Mar. 31, 2024	$ 1,243.9	$ 1.1	$ 1,523.4	$ (118.0)	$ 10.3	$ (172.9)	$ 507.1
Balance, Shares at Mar. 31, 2024		107.9					0.5