Derivative Financial Instruments - Additional Information (Details) - CAD ($) $ in Millions	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Canadian Dollar Forward Contract
Derivative [Line Items]
Foreign currency forward contract to hedge	$ 7.0	$ 30.0
Canadian Subsidiary
Derivative [Line Items]
Denominated intercompany accounts payable	$ 9.3	$ 20.4

Amount for accounts payable to related parties.

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