(Loss) Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Income per common share
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 52.1	$ (204.2)	$ 114.1
Less: Net income attributable to noncontrolling interests	9.0	9.0	7.0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	$ 43.1	$ (213.2)	$ 107.1
Weighted-average shares outstanding-basic (in shares)	70,700,000	70,400,000	69,800,000
Effect of dilutive stock options and unvested time-based restricted stock (in shares)	100,000	0	300,000
Weighted average shares outstanding-diluted (in shares)	70,800,000	70,400,000	70,100,000
(Loss) earnings per share-basic (in dollars per share)	$ 0.61	$ (3.00)	$ 8.16
(Loss) earnings per share-diluted (in dollars per share)	$ 0.61	$ (3.00)	$ 8.13
Performance Shares
Income per common share
Shares with anti-dilutive effect excluded from the computation of diluted earnings per share	552,000	438,000	349,000
Stock Option Awards and Time Based Stock Awards
Income per common share
Shares with anti-dilutive effect excluded from the computation of diluted earnings per share	1,000,000.0	1,100,000	200,000