Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
Apr. 30, 2021	Apr. 30, 2020
Income Tax Disclosure [Abstract]
Effective tax rates	13.10%	4.80%
Excess tax benefits recognized	$ 17,451	$ 19,615

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Name:	us-gaap_EffectiveIncomeTaxRateContinuingOperations
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration