Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended			7 Months Ended	9 Months Ended		12 Months Ended
	Dec. 31, 2017	Jul. 31, 2018	Jan. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2018	Jul. 31, 2017	Oct. 31, 2018
Income Tax [Line Items]
Effective tax rates		22.70%		28.80%		15.60%	29.80%
U.S. federal corporate income tax rate	35.00%				21.00%
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		$ 544				$ 7,494
Lapse of statute of limitations		$ 1,041
Discrete tax expense related to nondeductible acquisition costs							$ 2,600
Scenario Plan
Income Tax [Line Items]
U.S. federal corporate income tax rate								23.30%