Earnings (Loss) Per Share of Common Stock - Reconciliation of Numerator and Denominator for Basic and Diluted Earnings (loss) Per Share Calculation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Net (loss)	$ (20.5)	$ (3.6)	$ (33.1)	$ (12.4)
Weighted average number of common shares outstanding – basic and diluted	103,651,000	102,785,000	103,478,000	102,643,000
Basic and diluted (loss) per share	$ (0.20)	$ (0.04)	$ (0.32)	$ (0.12)
Weighted average number of anti-dilutive options and restricted stock	8,453,000	4,845,000	8,030,000	5,102,000