Consolidated Statements of Changes in Stockholders' Equity and Mezzanine 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, 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)	40.8			40.8
Other comprehensive income (loss), net of tax	(6.4)				(6.4)
Capital contributions and issuance of common stock	0.8		0.8
Capital contributions and issuance of common stock, Shares		1.4
Equity-based compensation	15.1		15.1
Repurchase of common stock and distributions	(3.1)					(3.1)
Series A Preferred Stock dividends	(26.7)		(26.7)				$ 8.9
Balance at Jun. 30, 2024	1,263.8	$ 1.1	1,520.0	(94.5)	10.7	(173.5)	$ 507.1
Balance, Shares at Jun. 30, 2024		108.0					0.5
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
Net Income (Loss)	23.5			23.5
Other comprehensive income (loss), net of tax	0.4				0.4
Capital contributions and issuance of common stock	0.4	$ 0.1	0.4
Equity-based compensation	5.1		5.1
Repurchase of common stock and distributions	(0.6)					(0.6)
Series A Preferred Stock dividends	(8.9)		(8.9)
Balance at Jun. 30, 2024	1,263.8	$ 1.1	1,520.0	(94.5)	10.7	(173.5)	$ 507.1
Balance, Shares at Jun. 30, 2024		108.0					0.5
Balance at Sep. 30, 2024	1,275.3	$ 1.1	1,518.1	(68.9)	(1.5)	(173.5)	$ 507.1
Balance, Shares at Sep. 30, 2024		108.2					0.5
Net Income (Loss)	28.3			28.3
Other comprehensive income (loss), net of tax	0.9				0.9
Capital contributions and issuance of common stock	2.9		2.9
Capital contributions and issuance of common stock, Shares		1.3
Equity-based compensation	13.6		13.6
Repurchase of common stock and distributions	(14.6)					(14.6)
Series A Preferred Stock dividends	(26.8)		(26.8)
Balance at Jun. 30, 2025	1,279.6	$ 1.1	1,507.8	(40.6)	(0.6)	(188.1)	$ 507.1
Balance, Shares at Jun. 30, 2025		109.5					0.5
Balance at Mar. 31, 2025	1,261.3	$ 1.1	1,511.4	(72.9)	2.3	(180.6)	$ 507.1
Balance, Shares at Mar. 31, 2025		109.4					0.5
Net Income (Loss)	32.3			32.3
Other comprehensive income (loss), net of tax	(2.9)				(2.9)
Capital contributions and issuance of common stock	0.7		0.7
Capital contributions and issuance of common stock, Shares		0.1
Equity-based compensation	4.6		4.6
Repurchase of common stock and distributions	(7.5)					(7.5)
Series A Preferred Stock dividends	(8.9)		(8.9)
Balance at Jun. 30, 2025	$ 1,279.6	$ 1.1	$ 1,507.8	$ (40.6)	$ (0.6)	$ (188.1)	$ 507.1
Balance, Shares at Jun. 30, 2025		109.5					0.5