Financial Instrument [Line Items]

No definition available.

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- Definition

Marketable securities remaining maturity.

+ References

No definition available.

+ Details

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CC
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL109998890-113959

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Amount of unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash inflow from sale, maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3151-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3179-108585

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-URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26853-111562

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Details

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- Details

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- Details

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- Details

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Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020	Apr. 30, 2021
Financial Instrument [Line Items]
Sale/maturities of available-for-sale marketable securities	$ 14.3	$ 16.7	$ 36.0	$ 28.4
Unrealized gains relates to equity securities			8.1	11.2
Not Designated as Hedge Instrument \| Foreign Exchange Forward Contracts
Financial Instrument [Line Items]
Foreign currency gains (losses)	0.4	$ (0.5)	0.5	$ 0.3
Not Designated as Hedge Instrument \| Foreign Exchange Forward Contracts \| Income Taxes And Other Receivables \| Derivatives Purchased
Financial Instrument [Line Items]
Derivative notional amount	90.0		90.0		$ 69.4
Not Designated as Hedge Instrument \| Foreign Exchange Forward Contracts \| Income Taxes And Other Receivables \| Derivatives Sold
Financial Instrument [Line Items]
Derivative notional amount	$ 44.4		$ 44.4		$ 44.9
Available-for-sale Marketable Securities \| Minimum
Financial Instrument [Line Items]
Marketable securities remaining maturity			1 month
Available-for-sale Marketable Securities \| Maximum
Financial Instrument [Line Items]
Marketable securities remaining maturity			23 months