Accumulated Other Comprehensive Income (Loss) Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	$ (25.5)		$ (24.6)
Other comprehensive loss	(0.9)	$ (5.4)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(21.0)		(20.1)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(0.9)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(4.5)		(4.5)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0.0
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net	(25.5)		$ (24.6)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(0.9)
Other comprehensive loss	$ (0.9)