Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2018	Dec. 31, 2017	Jan. 31, 2018	Jan. 31, 2017	Oct. 31, 2018
Income Tax [Line Items]
Effective tax rates			(1.00%)	29.00%
U.S. federal corporate income tax rate	21.00%	35.00%
Provisional tax benefit due to revaluation of tax assets and liabilities at reduced corporate tax rate			$ 45,213
Provisional tax expense to reflect the transition tax on previously deferred foreign earnings			23,124
Decrease in income tax expense			$ 22,089
Payment of transition tax in installments, period			8 years
Discrete tax benefit			$ 4,748
Scenario, Forecast
Income Tax [Line Items]
U.S. federal corporate income tax rate					23.30%