Share-Based Compensation Expense Included in Selling, General and Administrative Expenses in Consolidated Statements of Income (Parenthetical) (Detail) $ in Thousands	3 Months Ended
Apr. 30, 2020 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reversal of share-based compensation expense \| $	$ 653
Performance Stock Units (PSUs) \| Deferred Compensation, Share-based Payments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, granted \| shares	46,665

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration