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.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments.

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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Derivative Instruments - Gains (Losses) Associated with Foreign Currency Forward Contracts (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments, gain (loss) expected to be reclassified from accumulated OCI within the next 12 months			$ 14,000
Other income (expense), net
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency forward contracts not designated as hedges	$ 2,229	$ 1,884	4,627	$ 3,678
Designated as Hedging Instrument \| Revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from AOCI into income	896		912
Gains (losses) reclassified from AOCI into income		(1,960)		(3,077)
Designated as Hedging Instrument \| Other income (expense), net
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in income (amount excluded from effectiveness testing and ineffective portion)	0		0
Gains (losses) recognized in income (amount excluded from effectiveness testing and ineffective portion)		4,027		6,258
Designated as Hedging Instrument \| Net change in market value of effective foreign currency forward exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in OCI	$ 21,928		$ 37,790
Gains (losses) recognized in OCI		$ 17,891		$ 36,165