Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended
Dec. 31, 2017	Jan. 31, 2020	Jan. 31, 2019
Income Tax Disclosure [Abstract]
Effective tax rates		17.60%	28.60%
U.S. federal corporate income tax rate	35.00%	21.00%
Provisional discrete tax (benefit) expense			$ 4,866
Income tax provision included discrete tax benefit due to share-based payment transactions		$ 2,537	$ 868

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of income tax expense (benefit) for remeasurement of deferred tax from change in tax rate pursuant to Tax Cuts and Jobs Act.

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