Earnings per Share - EPS Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Income from Continuing Operations	$ 54.7	$ 55.7	$ 19.6
Undistributed Earnings Allocated to Participating Securities - Continuing Operations	(1.0)	(1.3)	(0.5)
Income from continuing operations allocated to common shareholders	53.7	54.4	19.1
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	0.0	0.0	(0.3)
Undistributed Earnings Allocated to Participating Securities - Discontinued Operations	0.0	0.0	0.0
Income from discontinued operations allocated to common shareholders	0.0	0.0	(0.3)
Diluted net income	54.7	55.7	19.3
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	(1.0)	(1.3)	(0.5)
Diluted net income allocated to common shareholders	$ 53.7	$ 54.4	$ 18.8
Weighted Average Number of Shares Outstanding, Basic	18,410,561	18,525,374	18,528,302
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Share-based Awards For Diluted Earnings Per Share Calculation	214,811	406,861	604,000
Diluted weighted-average shares	18,625,372	18,932,235	19,132,302