Condensed Consolidated Statement of Stockholders' Equity - USD ($)	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, 2017	$ 0	$ 0.2	$ (46.3)	$ 259.0	$ 261.5	$ (24.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(6.9)				(6.9)
Other comprehensive loss	(2.2)					(2.2)
Exercise of stock options	0			0.8
Share-based Compensation	0			1.6
Balances as of end of period at Dec. 31, 2017	0	0	0	0	0	0
Balances as of beginning of period at Sep. 30, 2018	505.3	0.2	(46.3)	267.5	317.0	(33.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	18.2				18.2
Other comprehensive loss	0.3					0.3
Exercise of stock options	0			0.3
Share-based Compensation	0			1.9
Balances as of end of period at Dec. 31, 2018	$ 526	$ 0	$ 0	$ 0	$ 0	$ 0