Project Assets - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2021 USD ($)	Apr. 30, 2020 USD ($)	Apr. 30, 2021 USD ($) item	Apr. 30, 2020 USD ($)	Oct. 31, 2020 USD ($) item
Project Assets [Abstract]
Number of project assets | item			8		8
Sale leaseback transaction, net book value	$ 89.3		$ 89.3		$ 70.5
Project asset depreciation	3.3	$ 2.8	7.3	$ 5.8
Long-term project assets construction in progress	97.9		97.9		91.3
PPA assets construction in progress	$ 4.8		$ 4.8		$ 4.8