Derivative Instruments - Effect of Derivative Instruments on Statements of Income (Detail) - Cash Flow Hedging - USD ($) $ in Thousands	6 Months Ended
	Feb. 28, 2018	Feb. 28, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in income on derivatives	$ 1,932	$ 543
Gain (loss) recognized in OCI on derivatives (effective portion)	2,472	(2,563)
Gain (loss) reclassified from accumulated OCI into income (effective portion)	784	(4,068)
Gain (loss) recognized on derivative (ineffective portion and amount excluded from effectiveness testing)	478	(3,255)
Foreign Exchange Forward
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in OCI on derivatives (effective portion)	1,222	(3,592)
Foreign Exchange Forward | Interest and Foreign Exchange
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in income on derivatives	1,933	520
Foreign Exchange Forward | Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from accumulated OCI into income (effective portion)	1,430	(3,096)
Gain (loss) recognized on derivative (ineffective portion and amount excluded from effectiveness testing)	282	(3,355)
Foreign Exchange Forward | Cost Of Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in OCI on derivatives (effective portion)	(223)	(435)
Gain (loss) reclassified from accumulated OCI into income (effective portion)	(373)	(346)
Gain (loss) recognized on derivative (ineffective portion and amount excluded from effectiveness testing)	196	100
Interest rate swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in OCI on derivatives (effective portion)	1,473	1,464
Interest rate swap contracts | Interest and Foreign Exchange
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) recognized in income on derivatives	(1)	23
Gain (loss) reclassified from accumulated OCI into income (effective portion)	$ (273)	$ (626)