Consolidated Statements of Operations - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net service revenues	$ 2,774.6	$ 2,553.6	$ 2,346.0
Cost of services provided	2,099.8	1,902.8	1,750.7
Gross profit	674.8	650.8	595.3
Selling, general and administrative expense	534.9	508.0	527.4
Amortization expense	51.5	52.3	55.8
Income from operations	88.4	90.5	12.1
Other expense (income)	15.5	(2.7)	(1.3)
Interest expense	53.3	42.3	64.6
Income (loss) before income taxes	19.6	50.9	(51.2)
Income tax expense (benefit)	5.6	4.6	(9.6)
Net income (loss)	$ 14.0	$ 46.3	$ (41.6)
Basic income (loss) per share	$ 0.14	$ 0.44	$ (0.40)
Diluted income (loss) per share	$ 0.14	$ 0.44	$ (0.40)