Property And Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense of property and equipment	$ 73.4	$ 85.9	$ 93.5
Outside of U.S.
Property, Plant and Equipment [Line Items]
Long-lived assets	$ 18.9	$ 19.1	$ 23.6

The expense recognized in the current period that allocates the cost of nonproduction tangible assets over their useful lives.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

Name:	us-gaap_DepreciationNonproduction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e9038-108599

+ Details

Name:	us-gaap_NoncurrentAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_StatementGeographicalAxis=us-gaap_NonUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: