Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Earnings Including Redeemable Noncontrolling Interest	$ 2.5	$ 18.6	$ 35.4	$ 50.4
Hedging adjustments:
Net loss on derivatives	0.0	(11.0)	0.0	(10.4)
Reclassifications to net earnings	0.6	(0.2)	1.1	(0.2)
Foreign currency translation adjustments:
Unrealized foreign currency translation adjustments	(0.9)	(0.3)	0.0	0.2
Tax benefit on other comprehensive loss:
Net loss on derivatives	0.0	0.8	0.0	0.8
Total Other Comprehensive (Loss) Income Including Redeemable Noncontrolling Interest	(0.3)	(10.7)	1.1	(9.6)
Less: Comprehensive income attributable to redeemable noncontrolling interest	1.7	6.2	27.8	32.5
Total Comprehensive Income Available to Class A Common Stockholders	$ 0.5	$ 1.7	$ 8.7	$ 8.3