XML 61 R50.htm IDEA: XBRL DOCUMENT
v3.19.1

Stock-based Compensation Expense (Intrinsic Value of Options Exercised) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Apr. 30, 2019 | Apr. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |  |
Pre-tax intrinsic value of options exercised | $ 8.4 | $ 3.4

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References 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 (d)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration