Share-based Compensation and Employee Benefit Plans - Cost of Defined Contribution Plan (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Contributions	$ 2.7	$ 2.6	$ 7.9	$ 7.8
Cost of sales and operating expense
Defined Benefit Plan Disclosure [Line Items]
Contributions	1.1	1.0	3.1	3.0
Selling, general and administrative expenses
Defined Benefit Plan Disclosure [Line Items]
Contributions	$ 1.6	$ 1.6	$ 4.8	$ 4.8