Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net earnings including redeemable noncontrolling interest	$ 165.5	$ 116.0	$ 114.4
Hedging adjustments:
Reclassifications to net earnings	0.0	7.1	2.3
Foreign currency translation adjustments:
Unrealized foreign currency translation adjustments	1.2	(2.9)	(0.2)
Tax (expense) benefit on other comprehensive income (loss):
Reclassifications to net earnings	0.0	(0.4)	(0.2)
Total Other Comprehensive Income Including Redeemable Noncontrolling Interest	1.2	3.8	1.9
Comprehensive income attributable to redeemable noncontrolling interest	0.0	38.3	88.2
Total comprehensive income available to common stockholders	$ 166.7	$ 81.5	$ 28.1