Derivative Financial Instruments - Additional Information (Details) - USD ($) $ in Millions		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2017	Sep. 30, 2016
Canadian Dollar Forward Contract
Derivative [Line Items]
Foreign currency forward contract to hedge	$ 3.0
Foreign currency forward contract term		90 days
Canadian Subsidiary
Derivative [Line Items]
Denominated intercompany accounts payable	27.1	$ 27.1	$ 27.1
Denominated intercompany accounts payable, short-term nature	2.9	2.9
Denominated intercompany accounts payable, long-term nature	$ 24.2	$ 24.2