Income Taxes - Valuation Allowance of Gross Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Valuation allowance against gross deferred tax assets:
Valuation allowance, beginning balance	$ 185,898	$ 1,489,780	$ 1,495,672
Additions	23,720	0	0
Deductions	66,968	1,303,882	5,892
Valuation allowance, ending balance	$ 142,650	$ 185,898	$ 1,489,780