Commitments and Contingencies (Details) $ in Thousands, $ in Millions	3 Months Ended			35 Months Ended
	Jan. 31, 2020 USD ($) government_entity	Jan. 31, 2020 CAD ($) government_entity	Jan. 31, 2019 USD ($)	Jan. 31, 2020 USD ($)	Jan. 31, 2020 CAD ($)	Jan. 31, 2020 CAD ($)
Loss Contingencies [Line Items]
Maximum amount of Canadian grant	$ 43,500			$ 43,500		$ 57.6
Number of Canadian government entities | government_entity	3	3
Total revenue | $	$ 832,912		$ 778,527
Amounts receivable from grant	9,100			9,100		$ 12.0
Grants
Loss Contingencies [Line Items]
Total revenue	$ 2,700	$ 3.6		$ 24,600	$ 32.5