Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net Income (Loss) Attributable to Parent	$ 6.0	$ 45.3	$ 64.2	$ 72.4
Average Common Shares Outstanding - Basic (in shares)	65,795	65,406	65,567	65,300
Add potential effect of exercise of stock options and other unvested equity awards (in shares)	1,893	1,146	1,733	1,102
Average shares outstanding - Diluted (in shares)	67,688	66,552	67,300	66,402
Net income attributable to common shareholders per common share - Basic (usd per share)	$ 0.09	$ 0.69	$ 0.98	$ 1.11
Net income attributable to common shareholders per common share - Diluted (usd per share)	$ 0.09	$ 0.68	$ 0.95	$ 1.09
Shares with anti-dilutive effect excluded from the computation of Diluted EPS (in shares)	2	557	225	502