Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net Earnings Including Redeemable Noncontrolling Interest	$ 38.5	$ 14.2	$ 73.9	$ 64.6
Hedging adjustments:
Net loss on derivatives	0.0	0.0	0.0	(10.4)
Reclassifications to net earnings	0.6	0.6	1.7	0.4
Foreign currency translation adjustments:
Unrealized foreign currency translation adjustments	0.3	0.4	0.3	0.6
Tax (expense) benefit on other comprehensive income (loss):
Net loss on derivatives	0.0	0.0	0.0	0.8
Reclassifications to net earnings	(0.1)	(0.1)	(0.1)	(0.1)
Total Other Comprehensive Income (Loss) Including Redeemable Noncontrolling Interest	0.8	0.9	1.9	(8.7)
Less: Comprehensive income attributable to redeemable noncontrolling interest	29.6	11.6	57.4	44.1
Total Comprehensive Income Available to Class A Common Stockholders	$ 9.7	$ 3.5	$ 18.4	$ 11.8