Property and Equipment, net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Property, Plant and Equipment [Line Items]
Depreciation	$ 9.4	$ 7.0	$ 6.6
Furniture and Fixtures, Gross	8.7	7.2
Capitalized Computer Software, Gross	30.5	25.3
Machinery and Equipment, Gross	24.7	22.6
Leasehold Improvements, Gross	17.0	15.4
Property, Plant and Equipment, Gross	80.9	70.5
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	38.5	31.8
Property, Plant and Equipment, Net	$ 42.4	$ 38.7
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