Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 45.0	$ 26.9	$ 83.2	$ 47.7
Weighted average number of common shares	50,147,639	49,943,373	50,106,735	49,916,927
Dilutive effect of stock-based compensation	479,318	67,166	437,784	37,854
Adjusted weighted average number of common shares	50,626,957	50,010,539	50,544,519	49,954,781
Basic net income per common share	$ 0.90	$ 0.54	$ 1.66	$ 0.95
Diluted net income per common share	$ 0.89	$ 0.54	$ 1.65	$ 0.95