Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net service revenues	$ 651.9	$ 559.1	$ 1,206.3	$ 1,129.8
Cost of services provided	493.8	426.8	914.6	854.5
Gross profit	158.1	132.3	291.7	275.3
Selling, general and administrative expense	127.9	126.9	251.3	257.1
Amortization expense	12.5	13.6	26.4	27.1
Income (loss) from operations	17.7	(8.2)	14.0	(8.9)
Other income (expense)	0.5	(1.9)	2.0	(1.3)
Interest expense	9.6	17.1	23.1	34.5
Income (loss) before income taxes	8.6	(27.2)	(7.1)	(44.7)
Income tax expense (benefit)	2.3	(6.7)	(1.4)	(11.6)
Net income (loss)	$ 6.3	$ (20.5)	$ (5.7)	$ (33.1)
Income (loss) per share:
Basic and diluted	$ 0.06	$ (0.20)	$ (0.05)	$ (0.32)