Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Financial Instrument [Line Items]

+ References

No definition available.

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- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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- Definition

Fixed interest rate related to the interest rate derivative.

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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/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

Date the derivative contract matures, in CCYY-MM-DD format.

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- Definition

The cash inflow associated with the sale or maturity (principal being due) of securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a),(b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26853-111562

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Financial Instruments - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2017	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Financial Instrument [Line Items]
Proceeds from maturities of available-for-sale marketable securities				$ 13,100,000
Maximum
Financial Instrument [Line Items]
Derivative gains included in AOCI		$ 400,000
Not Designated as Hedge Instrument \| Foreign Exchange Forward Contracts
Financial Instrument [Line Items]
Foreign currency gains (losses)		(3,700,000)	$ 600,000	$ (1,800,000)
Not Designated as Hedge Instrument \| Foreign Exchange Forward Contracts \| Other Accrued Liabilities \| Derivatives Purchased
Financial Instrument [Line Items]
Derivative notional amount		80,800,000	19,400,000
Not Designated as Hedge Instrument \| Foreign Exchange Forward Contracts \| Other Accrued Liabilities \| Derivatives Sold
Financial Instrument [Line Items]
Derivative notional amount		78,500,000	$ 70,000,000
Designated as Hedge Instrument \| Interest Rate Swap \| Cash Flow Hedge
Financial Instrument [Line Items]
Derivative notional amount	$ 129,800,000	$ 119,500,000
Derivative, Maturity Date	Jun. 15, 2021
Interest rate		1.919%