Condensed Consolidated Statement of Stockholders' Equity - 9 months ended Jun. 30, 2015 - USD ($) $ in Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balances as of beginning of period at Sep. 30, 2014	$ 345.4	$ 0.2	$ (17.5)	$ 229.6	$ 144.7	$ (11.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	34.6				34.6
Other comprehensive loss	1.3					1.3
Exercise of stock options	3.0			3.0
Share-based Compensation	2.8			2.8
Repurchase of stock	(4.7)		(4.5)	(0.2)
Balances as of end of period at Jun. 30, 2015	$ 382.4	$ 0.2	$ (22.0)	$ 235.2	$ 179.3	$ (10.3)