Derivative Instruments - Effect of Derivative Instruments on Statements of Income (Detail) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended
Nov. 30, 2018	Nov. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income on derivatives	$ 380	$ 363
Gain (loss) recognized in OCI on derivatives (effective portion)	(3,196)	1,147
Gain (loss) reclassified accumulated OCI income (effective portion)	(632)	344
Gain (loss) recognized on derivative (ineffective portion and amount excluded from effectiveness testing)	604	138
Foreign Exchange Forward
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in OCI on derivatives (effective portion)	72	730
Foreign Exchange Forward \| Interest and Foreign Exchange
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income on derivatives	380	380
Foreign Exchange Forward \| Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified accumulated OCI income (effective portion)	256	710
Gain (loss) recognized on derivative (ineffective portion and amount excluded from effectiveness testing)	262	56
Foreign Exchange Forward \| Cost Of Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in OCI on derivatives (effective portion)	(1,495)	(354)
Gain (loss) reclassified accumulated OCI income (effective portion)	(232)	(199)
Gain (loss) recognized on derivative (ineffective portion and amount excluded from effectiveness testing)	389	82
Interest rate swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in OCI on derivatives (effective portion)	(1,773)	771
Interest rate swap contracts \| Interest and Foreign Exchange
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income on derivatives		(17)
Gain (loss) reclassified accumulated OCI income (effective portion)	(144)	$ (167)
Gain (loss) recognized on derivative (ineffective portion and amount excluded from effectiveness testing)	$ (47)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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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 before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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