CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Noncontrolling Interest
Common Stock, Shares, Outstanding		49,761,480
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Sep. 30, 2022	$ 1,199.3	$ 49.8	$ 640.6	$ 507.9	$ 1.0
Net income	20.8	0.0	0.0	20.8	0.0
Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture	0.0	0.0	0.0	0.0	0.0
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation	(0.1)	0.0	(0.1)	0.0	0.0
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition	0.6	0.0	0.6	0.0	0.0
Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance at Dec. 31, 2022	$ 1,220.6	$ 49.8	641.1	528.7	1.0
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		11,075
Common Stock, Shares, Outstanding		49,772,555
Common Stock, Shares, Outstanding	49,903,713	49,903,713
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Beginning Balance at Sep. 30, 2023	$ 1,369.9	$ 49.9	644.2	674.8	1.0
Net income	38.2	0.0	0.0	38.2	0.0
Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture	0.0	0.0	0.0	0.0	0.0
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation	(0.2)	0.0	(0.2)	0.0	0.0
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition	0.9	0.0	0.9	0.0	0.0
Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance at Dec. 31, 2023	$ 1,408.8	$ 49.9	$ 644.9	$ 713.0	$ 1.0
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture		6,000
Common Stock, Shares, Outstanding	49,909,713	49,909,713