Property and Equipment, net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Depreciation	$ 7.0	$ 6.6	$ 5.7
Furniture and Fixtures, Gross	7.2	6.8
Capitalized Computer Software, Gross	25.3	22.8
Machinery and Equipment, Gross	22.6	20.6
Leasehold Improvements, Gross	15.4	11.9
Property, Plant and Equipment, Gross	70.5	62.1
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	31.8	32.7
Property, Plant and Equipment, Net	$ 38.7	$ 29.4
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	10 years