Earnings (Loss) Per Share Antidilutive shares excluded from (loss) earnings per share (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock Options
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share, Amount	0.1	0.1	1.7	0.1
Stock Appreciation Rights
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share, Amount	0.0	0.0	0.1	0.0
Restricted Stock Awards
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share, Amount	0.1	0.0	0.9	0.0
Performance-based restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share
Antidilutive Securities Excluded from Computation of Earnings (Loss) Per Share, Amount	0.1	0.0	0.2	0.0