Segment and Geographic Data - Schedule of Revenues by Geographic Location (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Revenues by geographic location, based on the jurisdiction of the subsidiary entity receiving revenue credit for the sale
Revenues	$ 1,041.0	$ 917.7	$ 1,970.6	$ 1,712.5
U.S.
Revenues by geographic location, based on the jurisdiction of the subsidiary entity receiving revenue credit for the sale
Revenues	754.9	684.2	1,423.0	1,271.6
Canada
Revenues by geographic location, based on the jurisdiction of the subsidiary entity receiving revenue credit for the sale
Revenues	51.3	46.7	93.8	83.6
Other North America
Revenues by geographic location, based on the jurisdiction of the subsidiary entity receiving revenue credit for the sale
Revenues	33.6	12.7	66.6	25.2
Total North America Operations
Revenues by geographic location, based on the jurisdiction of the subsidiary entity receiving revenue credit for the sale
Revenues	839.8	743.6	1,583.4	1,380.4
EMEA
Revenues by geographic location, based on the jurisdiction of the subsidiary entity receiving revenue credit for the sale
Revenues	149.7	124.4	276.9	221.3
Asia
Revenues by geographic location, based on the jurisdiction of the subsidiary entity receiving revenue credit for the sale
Revenues	$ 51.5	$ 49.7	$ 110.3	$ 110.8